doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Teenage children of teenage mothers: Psychological,
behavioural and healt1h outcomes from an Australian
prospective longitudinal study
Mary Shawa,*, Debbie A. Lawlora, Jake M. Najmanb
a
b
University of Bristol, UK
University of Queensland, UK
Abstract
In many industrialised countries teenage pregnancy and teenage parenthood have in
recent years been identified as social and public health problems that need to be
tackled. A number of studies have looked at various outcomes for teenage mothers
and their offspring, and many report a strong association with poverty for the mother
both before and after having a child. Few studies, however, adequately control for
socioeconomic circumstances when examining health and related outcomes. Most
studies have focused on perinatal outcomes in the offspring with few looking at later
health and development. In Australia, where the rate of teenage pregnancy is
relatively high compared to other comparable countries, teenage pregnancy is a not
prominent policy concern. As such, Australia offers the opportunity to study the
outcomes of teenage parenthood in a country where there may be less stigma than in
countries that portray teenage parenthood as a major health and/or social problem.
This paper reports findings from the Mater-University Study of Pregnancy (MUSP)
and its outcomes, a prospective study of women, and their offspring, who received
antenatal care at a major public hospital (Mater Misericordiae Hospital) in South
Brisbane, Australia, between 1981 and 1984. We have examined the associations of
maternal age (< 18 years (n = 460) versus > 18 years (n = 4800)) at first antenatal
visit with offspring psychological, behavioural and health characteristics when the
offspring the teenage children of teenage mothers—were aged 14 years. Multiple
logistic regression was used to determine the effect of maternal and family
characteristics on associations between maternal age and childhood outcomes at age
14. Results show that the 14 year old offspring of mothers who were aged 18 years
and younger compared to those who were offspring of older mothers were more likely
to have disturbed psychological behaviour, poorer school performance, poorer reading
ability, were more likely to have been in contact with the criminal justice system and
were more likely to smoke regularly and to consume alcohol. However, maternal age
was not associated with health outcomes in their offspring at age 14 years. Indicators
of low socioeconomic position and maternal depression were also associated with
poorer psychological, cognitive and behavioural outcomes among 14 year olds. In
addition children from poorer socioeconomic backgrounds and whose mothers were
depressed were more likely to have self- reported poor health, asthma, to have been
admitted to hospital twice or more since birth and to be bed-wetters at age 14. The
associations between maternal age and psychological distress, school performance,
and smoking and alcohol use were all largely explained by socioeconomic factors,
maternal depression, family structure and maternal smoking. These findings confirm
*Corresponding author.
E-mail addresses: mary.shaw@bristol.ac.uk (M. Shaw), d.a.1awlor@bristo1.ac.uk (D.A. Lawlor),
j.najmans@ph.uq.edu.au (J.M. Najman).
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
that not all teenage mothers and their offspring have adverse outcomes, and that many
if not the majority have good outcomes.
Keywords: Teenage; Mother; Longitudinal; Australia; Child; Health outcomes;
Psychological behaviour
Introduction
The international policy context
In many industrialised countries teenage pregnancy and teenage parenthood
(regardless of marital status) have in recent years been identified as social and public
health problems that need to be tackled, though the level of concern varies by context.
A report by UNICEF (2001) asserts however that for most of history teenage
parenthood has not been perceived as a problem, but as something normal and
desirable; by contrast:
Today, parents, politicians and physicians warn against it... teenage parenthood has
come to be regarded as a significant disadvantage in a world which increasingly
demands an extended education, and in which delayed childbearing, smaller families,
two-income households, and careers for women are increasingly becoming the norm.
(UNICEF, 2001, pp. 5—6)
The UNICEF report categorises nations according to what degree fertility among
women aged below 20 is considered a matter of concern and whether government is
actively intervening to change that rate. This information is presented in Table 1,
which additionally categorises countries according to whether their fertility rate for
women under 20 is above or below 10/1000. Policy concern clearly varies by context:
some countries with lower rates exhibit ‘major’ concern (France, Spain) whereas
others with higher rates do not see this as a matter of concern (Czech Republic,
Iceland, Ireland and Slovak Republic). Similarly, interventions are not the exclusive
domain of countries with higher rates, although all countries which have identified
this as a ‘major’ concern were actively intervening.
In Australia, where the rate is in the higher category (18.4/1000), teenage pregnancy
is seen as of ‘minor’ concern with no active intervention in 1998 when the UNICEF
data were collated. By contrast in England, a raft of policy documents (e.g. HDA,
2005; SEU, 1999) have addressed this issue since it first appeared on the policy
agenda in the early l990s (DoH, 1992). Such attention in policy rhetoric and activity
in countries such as the US and UK, that are actively intervening to reduce teenage
pregnancy rates, is often justified with reference to the implications for welfare
dependency (in the US) and adverse health consequences for young mothers and their
offspring (in the UK) (Bonell, 2004).
Table 1 Teenage fertility and family planning policy: an international perspective
(birth rate per woman aged below 20/1000 women aged 15—19)
Rate< 10/l000a
Not a matter of concern Minor concern
Italy (6.6)
Belgium (9.9)
Major concern
France (93)
doi: 10. l016/j.socscimed.2005. 10.007
Luxembourg (9.7)
Netherlands (6.2)
Switzerland (5.5)
Rate >10/1000a
Czech Republic (16.4)
Iceland (24.7)
Ireland (18.7)
Slovak Republic (26.9)
Social Science and Medicine 62: 2526-2539
Denmark (8.1)
Finland (9.2)
Japan (4.6)
Korea (2.9)
Sweden (6.5)
Australia (18.4)
Austria (14.0)
Greece (11.8)
Hungary (26.5)
Norway (12.4)
Poland (18.7)
Spain (7.9)
Canada (20.2)
Germany (13.1)
New Zealand (29.8)
Portugal (21.2)
UK (30.8)
USA (52.1)
Notes: Countries marked in bold are those where government are actively intervening to change
fertility among women aged 20 and below.
Adapted from UNICEF (2001).
*Refers to rate of births per woman aged below 20/1000 15—19 year aids (data for 1998).
However, in terms of justifying why we would expect teenage mothers and their
offspring to have poor health outcomes, this area is relatively undertheorised—such
an effect is often assumed rather than explicitly justified. One form of argument is
that teenagers, although mature enough to become pregnant, are physiologically too
young to bear children successfully. Parallel to this is the position that teenagers are
too emotionally immature to be good parents, not yet able to provide their children
with the full range of support and stimulation they need. However, the most
predominant form of justification for examining the health (and other) outcomes for
teenage mothers and their children connects early childbearing intimately, and almost
inextricably, with poverty and its transmission across generations. Indeed, having
considered various outcomes for teenage mothers across Europe, Berthoud and
Robson suggest that “...teenage motherhood may be seen as conceptually equivalent
to poverty” (2001, p. 52, their emphasis). Studies which have sought to distinguish
the effects of young age from the adverse effects of poor socioeconomic
circumstances, however, tend to find that it is the latter which is the predominant
causal factor (Cunnington, 2001; Geronimus, 2003; Lawlor & Shaw, 2002).
Teenage pregnancy and socioeconomic circumstances
Teenage mothers are most likely to originate from poor families (Hobcraft & Kiernan,
2001) and younger mothers are more likely to have been brought up and currently live
in deprived areas than their older counterparts (McLeod, 2001; Van der Klis,
Westenburg, Chan, Dekker, & Keane, 2002). The relationship between deprived areas
and higher rates of teenage pregnancy, however, is reported to be largely due to
personal and household disadvantage rather than due to area effects (McCulloch,
2001).
Moreover, teenage parents also tend to remain poor and be relatively socially and
economically disadvantaged. Comparing teenage to older mothers across Europe,
Berthoud and Robson (2001) found that 40% of 18 year old mothers were living in
poverty when their child was 10 years old, compared to only 11% of 28 year old
mothers.
However, it is unclear whether becoming a teenage mother results in worsening
poverty or whether teenage mothers remain on the same socioeconomic trajectory that
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
they were on before becoming pregnant. Studies have looked at a range of
socioeconomic outcomes for young mothers in a variety of contexts. In Sweden,
Olausson, Haglund, Weitoft, and Cnattingius (2001) have reported that compared to
older mothers teenage mothers tended to be less likely to be employed, more likely to
not be living with a partner and more likely to be reliant on welfare benefits. In the
US, having a child before the age of 20 has been linked to lower rates of high school
completion and post-secondary education (Hofferth, Reid, & Mott, 2001) and to
significantly reduced educational attainment among white, blacks and Hispanics
(Klepinger, Lundberg, & Plotnick, 1995). Similar findings are reported in the UK
when younger mothers are compared with women who become mothers at older ages.
However, such comparisons cannot take into account “what the woman would have
done if she did not have a child as a teenager” (Ermisch & Pevalin, 2003a, p. 1).
Analysis of the British 1970 Cohort (Ermisch & Pevalin, 2003a) looking at various
outcomes for women aged 30 who had a teenage birth compared with those who
became pregnant as a teenager but who miscarried or had an abortion find little
evidence of any differences between these two groups on the woman’s qualifications,
employment or pay at age 30 (although they did find that at age 30, her partner, if she
did have one, was more likely to be unemployed). These findings suggest that the act
of becoming a teenage mother does not itself result in worsening outcomes for the
mother, rather women who become pregnant as a teenager remain on the same
trajectory whether they continue with the pregnancy or not.
Teenage pregnancy and adverse outcomes
Teenage mothers and their offspring are reported to have a range of negative
outcomes. There is evidence that teenage mothers are more likely to experience
depression around the perinatal period (Quinlivan, Tan, Steel, & Black, 2004) and
there may be slightly higher rates of perinatal death (ONS, 1997). Most research has
looked at the health outcomes of young offspring. It is reported that the children of
teenage mothers experience more health problems in the neonatal and early life period
compared to the children of older mothers.
Research from the British 1970 Cohort Study (Pevalin, 2003), for example, finds that
babies born to younger mothers are more likely to be born preterm and to be of low
birthweight, which may have a range of consequences. An American study looking at
the same outcomes found an increased risk of adverse outcomes for mothers aged less
than 20 even when controlling for confounding socioeconomic factors (Fraser,
Brockert, & Ward, 1995).
Some studies are able to consider longer-term outcomes. Hofferth and Reid (2002)
used data from the US National Longitudinal Survey of the Labor Market Experience
of Youth and the Panel Study of Income Dynamics to look at maternal age at first
birth (age 19 or younger) and outcomes for children age 3—13. They found that in
comparison with children of older women these children scored lower on achievement
tests and had higher rates of behavioural problems, although when period effects were
taken into account fewer achievement differences were found, thereby suggesting that
comparisons across cohorts may exaggerate effects. Fergusson and Woodward (1999)
looked at the relationship between maternal age at birth and outcomes at age 18 in a
New Zealand cohort and found that maternal age (as a general gradient, not just
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
comparing teenage mothers with older mothers) was associated with a wide range of
educational and psychosocial outcomes—i.e. risks of educational under-achievement,
juvenile crime, substance misuse, and mental health problems—such that younger
mothers had worse outcomes. However Fergusson and Woodward caution:
It is also important to recognise that although maternal age was related to later
outcomes, this relationship was by no means deterministic: the offspring of younger
mothers were not invariably disadvantaged and neither were the offspring of older
mothers invariable advantaged. Rather there were small, pervasive, and generally
consistent trends for outcome risks to decline with increasing maternal age. (1999, p.
487)
The outcome that is most commonly reported for the older offspring of teenage
mothers is that they are more likely themselves to become a teenage mother, thus
contributing to a ‘cycle of poverty’. Data from the British Household Panel Survey
and the British 1970 Cohort Survey show that those born to teenage mothers are twice
as likely to become teenage mothers themselves (Ermisch & Pevalin, 2003b). In the
US, Kahn and Anderson (1992) using data from the 1988 National Survey of Family
Growth (Cycle IV) found that both black and white teen mothers were significantly
more likely to be teen mothers than were daughters of older mothers. However, it is
certainly not the case that being born to a teenage mother means that a young woman
is herself necessarily destined to become a teenage mother results from a study of
black women in the US (who have high rates of teenage motherhood) find that the
majority do not become adolescent parents, although they did have “bleaker
educational and financial prospects than their mothers had” (Furstenburg, Levine, &
Brooks-Gunn, 1990, p. 54).
Whether these adverse effects associated with early childbearing are due to young age
per se or to poor socioeconomic circumstances, or to a combination of the two, the
conditions of early life may have repercussions for health and other outcomes much
later in life. Maternal depression in the perinatal period, for example, may in turn
influence the child’s early development and later cognitive ability and behaviours.
Neonatal problems and poor socioeconomic circumstances in early life are both
associated with adverse outcomes in later life, including cognitive performance and
coronary heart disease (Jefferis, Power, & Hertzman, 2002; Lawlor, Davey Smith, &
Ebrahim, 2004; Lawlor, Ronalds, Clark, Davey Smith, & Leon, 2005; Richards,
Hardy, & Kuh, 2001). Further, there is an increasing body of evidence linking
cognitive ability in childhood to increased risks of premature mortality,
cardiovascular disease and mental health problems in later life (Batty & Deary, 2004).
The Australian context
This paper draws on data from an Australian context. As in many industrialised
countries, overall fertility rates have been declining in Australia over the past 50
years. Moreover, women are increasingly delaying child-bearing: the median age at
child-bearing rose from 26.7 years in 1981 to 28.5 years in 1991 and 30.0 years in
2001. Between 1981 and 2001 there was a fall in the proportion of births to teenage
mothers, from 7.5% in 1981 to 4.8% in 2001 (ABS, 2004). The teenage fertility rate
(births per year per 1000 females aged 15—19) has been declining since the 1970s. It
peaked in 1971 at 55.5 births/1000 females, falling to 27.6/1000 in
1980 and reaching its lowest ever rate of 18.1 in 1999 (see Fig. 1). The decline is
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
thought to be due to increased access to sex education, contraception and abortion
(ABS, 2000). Despite similar rates to countries that see teenage births as a major
problem and/or that are actively intervening to reduce teenage pregnancy (for
example Canada, Germany, Portugal and Ireland) Australia does not see teenage
pregnancy as a major problem and does not have a policy aimed at reducing it. Thus,
Australia offers the opportunity to study the outcomes of teenage parenthood in a
country where there may be less stigma than in countries that portray teenage
parenthood as a major health and/or social problem.
Within Australia rates of teenage pregnancy are higher in rural areas (Evans, 2001),
more economically disadvantaged areas (Coory, 2000), and in indigenous
populations, with the birth rate for indigineous women aged 15—19 being 3.3 times
that for the general population in Queensland (ABS, 2000). In 1999 the rate for
Queensland was slightly higher than that for Australia as a whole, at 22.4/ 1000
(Coory, 2000).
What this study is about
The aim of this study is to examine, in an Australian cohort, the associations of
maternal age (18 years versus > 18 years at their first antenatal visit) with outcomes
among their 14 year-old offspring in terms of health and psychological and
behavioural characteristics. Further, we aim to establish the role of socioeconomic
factors and maternal characteristics, including maternal depression and health
characteristics, in explaining any observed associations. In choosing to dichotomise
maternal age we do not wish to imply that there is something unique about the age of
18, rather this choice reflects the approach used in those countries that have policy
interventions to reduce teenage pregnancies with teenage pregnancy in these policy
40 documents being defined by a cut-point of 18 or 19 years.
Methods
Participants
The Mater-University study of pregnancy (MUSP) and its outcomes is a prospective
study of women, and their offspring, who received antenatal care at a major public
hospital (Mater Misericordiae Hospital) in South Brisbane between 1981 and 1984
(see Keeping et al., 1989 for further demographic characteristics of the sample).
Consecutive women attending their first obstetric visit for their current pregnancy (not
necessarily their first) were invited to participate in the study (N = 8556). Pre- and
post-birth phases of data collection were undertaken prior to discharge from hospital.
Of the 8556 mothers invited to participate 98 mothers refused, 710 did not deliver a
live child at the public hospital (including 169 miscarriages and those who chose to
use other facilities), 59 mothers had multiple births, 312 did not complete the postbirth data collection phase, 99 children died during or immediately post- delivery and
55 children were adopted prior to discharge. In total 7223 (84% of mothers invited to
participate) agreed to participate and completed both initial phases of data collection;
these mothers and their offspring form the MUSP prospective cohort.
Mothers were interviewed at their first antenatal clinic visit, 3—5 days after birth, 6
months after birth, 5 and 14 years after birth. When the child was 14 years of age a
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
physical examination of and interview with the child were undertaken, in addition to
the maternal interview. In this study for the main analysis we have examined the
associations of maternal age (<18 years versus > 18 years) at first antenatal visit with
offspring psychological, behavioural and health characteristics when the offspring
were aged 14 years. In addition we have examined these associations with maternal
age categorised as <16 years versus > 16 years.
Measures of child psychological and cognitive behaviour
The Achenbach Youth Self Report (YSR) questionnaire was completed by the child at
age 14 years (Achenbach, 1991). The YSR includes 102 items of behavioural
problems and provides a self-report measure of current behavioural and psychological
status (Achenbach, 1991). As the children were involved in a large study with a
number of measurements the questions were reproduced on our own form and the
setting out simplified (Najman et al., 2001). Factor analyses and reliability estimates
of sub-scales produced results consistent with Achenbach’s data (Achenbach, 1991;
Najman et al., 2001). Cases of behavioural problems in each domain were identified
by the factor analysis (see domains listed in first column of Table 3 under
psychological and cognitive behaviour).
In addition the children were asked about their performance at school in three main
subject areas (English, Maths, Science) and their school performance overall.
Response options were ‘below average’, ‘a bit below average’, ‘average’, ‘a bit above
average’ and ‘above average’. Mothers were similarly asked about the child’s overall
school performance. In this paper for these variables children were dichotomised as
either below average (including a bit below) or average and above. Mothers were also
asked about whether the child had ever had to repeat a school year, had ever received
special education, had ever been suspended from school and also whether their child
had ever been reported to the child-guidance services or been in trouble with the
police.
At age 14, assessments of cognitive function were based on youth scores on Raven’s
standard progressive matrices (de Lemos, 1989) and the wide range achievements test
version 3 (WRAT3) (Wilkinson, 1993). The Raven’s standard progressive matrices
(Raven’s SMP) is a test of non-verbal reasoning ability that has been widely used for
psychological assessment in clinical and educational contexts, for research and for
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
personnel selection (de Lemos, 1989). The Raven’s SMP scores were age
standardised in 6-monthly intervals as data could not be collected at exactly the same
age for all children. The WRAT3 is an age-normed reference test that assesses reading
and word decoding skills (Wilkinson, 1993). It is reliable, predictive of future
educational attainment and has been widely used in research (Mishra, 1981;
Woodward, Santa-Barbara, & Roberts, 1975). Consistent with previous studies, both
cognitive development scores were categorised as low (at or below the 10th
percentile) or above the 10th percentile (O’Callaghan, Williams, Andersen, Bor, &
Najman, 1995).
Measures of health and health related behaviour of child at age 14 years
At age 14 years the children were asked whether their health over the last year had
been excellent, good, fair or poor. Those describing their health as fair or poor were
defined as having poor self- assessed health for the purpose of this analysis. They
were also asked how often they had smoked cigarettes in the week prior to interview
(responses allowed were—every day, every few days, once or so only, not at all) and
they were categorised as daily smokers in the previous week (first response only) or
other (all other responses). They were asked to report whether they usually drank
alcohol on a daily basis, a few times a week, a few times a month, a few times a year,
rarely or never. Since very few children drank daily or weekly (N = 8 and 52,
respectively for these responses) the participants were dichotomised into those
reporting drinking alcohol at least a few times a month versus those drinking less
frequently than this. Mothers were asked to report whether their children had ever
been diagnosed with a number of childhood illnesses and about medical care for
accidents and other health problems (see column 1 of Table 3 under heading ‘health
and health related problems’).
Maternal and family characteristics
Data on the family income during the year of the pregnancy (7 categories), marital
status (single, cohabiting, married, divorced or separated) and education (up to:
special school, primary school, secondary school, completed 10th grade, completed
12th grade, college, university) of the mothers were also obtained from the obstetric
records. When the child was age 14 the mothers were asked details about current
family income (7 categories) and also about whether she was currently living with the
child’s biological father, living alone or living with others. Family poverty at both
birth and age 14 years was defined as those in the two lowest categories of family
income. Mothers were also asked (when the child was age 14 years) a series of 9
questions relating to the area in which they lived (whether vandalism/graffiti, house
burglaries, car stealing, drug abuse, violence in the streets, unemployment, reckless
driving, alcohol abuse, school truancy were a major, moderate, small or no problem in
their area). Responses to these questions were used to define the family as living in a
problem residential area or not.
Maternal depression was assessed at all phases of the study using the delusions—
symptoms—states inventory (DSSI) (Bedford & Foulds, 1978). The DSSI items were
administered to the mother in the form of a self-report questionnaire. The DSSI was
developed by clinicians and validated against a clinical sample. It contains a seven
item depression subscale which has been found to correlate strongly with other scales
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
of depression including the Beck’s Depression Inventory (Najman, Andersen, Bor,
O’Callaghan, & Williams, 2000). Consistent with previous work, in this study postnatal depression and maternal depression when the child was aged 14 were defined as
having 3 or more symptoms out of the 7 in the DSSI depression subscale (Najman et
al., 2000).
Statistical analyses
Student’s t test and chi-squared tests were used to compare values of exposures
(measured at the antenatal stage) between those children who were interviewed at age
14 years and those from the original birth cohort who were not. Measurements at age
14 years were age adjusted by the child’s exact age in days when they were examined
so that they reflected estimates at exactly 14 years for each child. Proportions of each
childhood and maternal characteristic by whether the mother was aged 18 years or
younger at her first antenatal visit or older than 18 years were estimated together with
crude odds ratios for these associations. Chi-squared tests were used to assess
differences between younger mothers and older mothers for each characteristic.
Multi- variable analyses were only conducted on those characteristics which were
found to differ by maternal age in the age (in days)-adjusted analyses. Multiple
logistic regression was used to determine the effect of maternal and family
characteristics on the associations between maternal age and childhood outcomes at
age 14. A series of regression models, which contained the following additional
covariates in addition to the child’s exact age in days at the 14 year follow-up, were
undertaken:
Model I (Gestational age at booking): gestational age (weeks) at first antenatal
(booking) clinic visit.
Model 2 (Socioeconomic position): gestational age (weeks) at first antenatal clinic
visit, family income during year of pregnancy, family income during 14th year of
child’s life, maternal education, living in a problem residential area during 14th year
of child’s life.
Model 3 (Maternal depression); gestational age (weeks) at first antenatal clinic visit,
maternal postnatal depression and maternal depression when the child was aged 14.
Model 4 (Family structure): gestational age (weeks) at first antenatal clinic visit,
marital status of mother during year of pregnancy, marital status of mother during
child’s 14th year, whether mother was living with biological father when child was
aged 14.
Model 5 (Maternal smoking): gestational age (weeks) at first antenatal clinic visit and
maternal smoking when child was age 14 years.
Model 6 (Fully adjusted): all covariates included in any of the models above.
Results
Of the 7223 original mother—offspring pair cohort members 5260 (73%) provided
data when the children were 14 years of age. Table 2 shows the differences in
maternal characteristics between those who were followed-up at age 14 and those who
were lost to follow-up. The mothers of children who were followed-up at age 14,
compared to those were not, were less likely to have been 18 years or younger at their
first antenatal visit. They were also less likely to have been smokers throughout their
pregnancy, single at the time of the pregnancy, to have experienced post-natal
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
depression, to have attended their first antenatal clinic visit at or after 25 weeks of
gestation and to be from low-income groups; they were more likely to have been
White. There was no difference with respect to mothers being educated to at least
10th grade between those who were followed-up and those who were lost to followup.
Table 2: Differences in maternal characteristics of children who were followedup at 14 years and those who were lost to follow-up
<18 years
Smoker throughout pregnancy
Single
Post-natal depression
First antenatal clinic visit at or
beyond 25 weeks of gestation
Educated to at least 10th grade
Family income <$5200 during
year of pregnancy
White
Prevalence (%) for
mothers of children
who were followed-up
N=5260
8.8
38.0
8.5
7.9
Prevalence (%) for
mothers of children who
were lost to follow-up
N=2401
13.3
51.5
15.6
11.7
p
<0.001
<0.001
<0.001
<0.001
16.3
27.4
<0.001
72.3
73.5
0.23
5.2
10.9
<0.001
93.9
88.1
<0.001
All further results refer only to the 5260 children who attended at age 14 years. Of
these 5260 children, 460 (8.7%) were born to mothers who were aged 18 years or
younger at their first antenatal visit and just 97 (1.8%) were born to mothers who were
aged 16 years or younger. In comparison to the national statistics cited above, which
include women aged 15—19, 13% of the MUSP sample were in this age group,
compared to 7.5% nationally in 1981. Table 3 shows the age-adjusted associations
between maternal age (<18 years versus > 18 years) and all measures of childhood
psychological, cognitive, behavioural and health-related characteristics as well as
maternal and family characteristics. Children born to mothers who were aged 18 years
or younger showed greater psychological distress in all domains of the YSR scale,
with these children compared to those born to older mothers having a 50% increased
odds of being in the highest 10% for the whole cohort of overall psychological
distress. Children born to mothers who were 18 years or younger also self-reported
that they were performing below average at school more frequently than those born to
older mothers and their mothers were more likely to report poor school performance.
With respect to objective measures of cognitive function children born to mothers
aged 18 years or younger were more likely to have repeated a school year and were
more likely to have a low WRAT score. However, Raven’s scores were similar
between the two groups. Children born to younger mothers were considerably more
likely to have been ever suspended from school, had contact with a childhood
guidance officer or had contact with the police or juvenile aid. However, with the
exception of having a large number of dental fillings (more common among children
of younger mothers) none of the child health outcome measures were associated with
maternal age. Children of young mothers were more likely to be regular smokers and
more likely to have consumed alcohol at least monthly than those of older mothers.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Table 3: Psychological, behavioural and health characteristics of 14 year old
children by whether their mothers were aged 18 years or younger or over 18
years at their first antenatal visit
Prevalence (%)
Maternal age at
Maternal age at
first antenatal
first antenatal
visits >18 years
visits < 18 years
N=4800
N=460
Psychological and cognitive behaviour of child age 14 years
YSR; withdrawn
9.7
11.3
YSR; somatic
8.9
12.0
YSR: Anxious/depressed
8.5
12.0
YSR: social problems
7.9
10.9
YSR: thought problems
8.7
12.2
YSR: attention problems
8.7
11.1
YSR: delinquent
7.8
13.9
YSR: aggressive
7.9
12.0
Overall YSR distress
9.3
13.5
Self-report below average school
13.2
17.3
performance English
Self-report below average school
21.2
24.2
performance maths
Self-report below average school
17.7
21.0
performance science
Self-report below average school
8.2
11.2
performance in general
Maternal report of below average
17.6
26.1
overall performance at
school
Ever had to repeat a school year
12.4
16.9
Ever received special education
6.9
9.4
Low raven score
10.5
10.5
Low WRAT score
10.2
14.2
Contact with criminal justice system
when child age 14 years
Ever been suspended from school
6.5
12.8
Had contact with guidance officer
24.4
34.7
Had contact with police or juvenile aid
8.7
17.0
Health and health related behaviour of child age 14 years
Self-report of poor health
19.0
19.3
Maternal report of diagnosis of asthma
28.2
28.7
Maternal report of any fracture
24.9
26.0
Maternal report of any accidents
19.9
23.0
requiring medical attention
Maternal report of 2 admissions to
22.4
25.0
hospital since birth
Maternal report of a large number of
4.4
7.0
dental fillings
Maternal report of bed-wetting at age
4.6
6.1
14
Daily smoking in previous week
4.0
8.1
At least monthly alcohol consumption
5.0
7.0
Maternal/family characteristics
Age-adjusteda odds
ratio (95% CI)
p
1.19 (0.88, 1.62)
1.38 (1.03, 1.90)
1.45 (1.08, 1.96)
1.43 (1.04, 1.95)
1.46 (1.09, 1.97)
1.31 (0.96, 1.78)
1.91 (1.44, 2.53)
1.58 (1.17, 2.14)
1.51 (1.13, 2.01)
0.25
0.03
0.01
0.03
0.01
0.08
<0.001
0.003
0.004
1.38 (1,07, 1.78)
0.02
1.20 (0.95, 1.49)
0.13
1.24 (0.98, 1.57)
0.07
1.40 (1.03, 1.91)
0.03
1.65 (1.33, 2.06)
<0.001
1.44(1.11, 1.86)
1.41 (1.01, 1.96)
1.00 (0.69, 1.45)
1.45 (1.04, 2.01)
0.006
0.05
1.0
0.03
2.12 (1.58, 2.86)
1.64 (1.34, 2.01)
2.16 (1.65, 2.83)
<0.001
<0.001
<0.001
1.02 (0.80, 1.30)
1.02 (0.83, 1.26)
1.06 (0.85, 1.32)
0.88
0.84
0.58
1.20 (0.96, 1.51)
0.11
1.15 (0.92, 1.44)
0.21
1.64 (1.12, 2.41)
0.01
1.33 (0.89, 2.00)
0.17
2.10 (1.46, 3.02)
1.44 (0.98, 2.11)
<0.001
0.06
doi: 10. l016/j.socscimed.2005. 10.007
First antenatal clinic visit at or beyond
25 weeks gestation
Maternal post-natal depression
Maternal depression when child aged
14
Low family income during year of
pregnancy of child
Low family income when child age 14
years
Living in problem residential area when
child age 14 years
Maternal education to grade 10 only
Mother single at time of pregnancy of
child
Mother living without partner when
child age 14
Mother living with biological father of
child when child aged 14
Mother smoker when child age 14
years
Social Science and Medicine 62: 2526-2539
24.7
18.8
1.41 (1.18, 1.70)
<0.001
8.7
11.0
1.30 (1.02, 1.66)
0.04
12.0
17.8
1.59 (1.23, 2.05)
<0.001
6.1
18.3
3.46 (2.85, 4.20)
<0.001
9.2
7.8
0.83 (0.58, 1.19)
0.32
8.2
9.9
1.23 (0.89, 1.70)
0.21
71.3
85.1
2.31 (1.90, 2.80)
<0.001
7.3
44.0
9.99 (8.51, 11.70)
<0.001
13.9
11.7
0.83 (0.61, 1.11)
0.20
69.9
45.7
0.36 (0.30, 0.44)
<0.001
29.2
51.0
2.52 (2.08, 3.05)
<0.001
YSR: Achenbach’s Youth Self Report scale see text under methods ‘measures of child psychological
and cognitive behaviour’ for further details.
a
Adjusted for exact age in days at time of 14 year old interview.
Young mothers were more likely to have attended their first antenatal clinic in late
gestation, to have experienced post-natal depression and been depressed when the
child was age 14, to have lower levels of family income, to have poorer education, to
be living in problem residential areas, to have been single when the child was born
and were less likely to be living with the biological father of the child when the child
was aged 14 years (Table 3). These indicators of family and maternal deprivation
were associated with poorer psychological, cognitive and behavioural child outcomes
(at age 14), with the magnitudes of these associations being similar to those found for
maternal age at pregnancy (data not shown). Further, measures of socioeconomic
disadvantage, unlike maternal age, were associated with poor health outcomes in the
children at age 14 years. For example, the crude odds ratio (95% confidence interval)
of a self-report of poor health associated with low family income at age 14 was 1.41
(1.13, 1.77), that of having asthma was 1.38 (1.13, 1.69), that for bedwetting was 1.38
(0.98, 2.07) and that for two or more hospital admissions since birth was 1.42 (1.15,
1.76). Accidents requiring medical attention were not associated with low income.
The crude odds ratio (95% confidence interval) of a self-report of poor health
associated with maternal depression when the child was aged 14 was 1.41 (1.13,
1.77), that of having asthma was 1.21 (1.01, 1.44), that for bedwetting was 1.62 (1.15,
2.26) and that for two or more hospital admissions since birth was 1.35(1.11, 1.63).
Accidents requiring medical attention were not associated with maternal depression
when the child was aged 14.
Table 4 shows the effect of adjustment for gestational age at booking clinic,
socioeconomic position, maternal depression, family organisation and maternal
smoking on the associations between maternal age and poor psychological, cognitive
and behavioural outcomes in the child at age 14 years. All analyses in this table are
based on the 4976 (95%) of participants included in this paper who had complete data
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
on all variables in the final fully adjusted model. In this way any changes in the odds
ratios with adjustments for different groups of covariates cannot be explained by
different subgroups being used in different multivariable models. There were no
important differences between any of the outcomes considered in those with complete
data on all covariates and those without these complete data (all p-values >0.4). The
increased odds of YSR mental distress associated with young maternal age was
markedly attenuated with adjustment for maternal depression, family structure and
maternal smoking, and modestly attenuated by adjustment for socioeconomic
position. With full adjustment for socioeconomic position, family structure and all
maternal characteristics the association was attenuated to the null. The association
between childhood problems with the police or school guidance at age 14 was
modestly attenuated by all of the covariates though a small association remained in
the fully adjusted model. The association between school performance at age 14 (both
self reported and maternal reported) and maternal age was attenuated by adjustment
for each of socioeconomic position, maternal depression, family structure and
maternal smoking, and similarly the associations of maternal age and childhood
smoking and alcohol behaviour were fully explained by socioeconomic position,
family structure and maternal characteristics. Socioeconomic circumstances and other
confounding factors did not seem to explain any of the association between maternal
age and child cognitive function as assessed by the WRAT3 reading scale at age 14
nor did they explain the association with dental caries (as indicated by a history of a
large number of fillings). When analyses were repeated using a cut-off in maternal
age at first booking of 16 years rather than 18 years all point estimates were
essentially unchanged from those presented here, though confidence intervals were
wider (data not shown).
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Table 4: Multivariable associations of being born to a teenage mother with behavioural and health characteristics of child at age 14years
Overall YSR distress
Any trouble with
police/childhood
guidance/suspended
from school
Self-report of overall
below average
performance at school
Maternal report of
overall below average
performance at school
Low WRAT score
Daily smoking in
previous week
At least monthly
alcohol consumption
Large number of dental
fillings
Gestational age
at first antenatal
clinic visit
adjusted odds
ratio (95% CI)
1.67 (1.24, 2.25)
Socioeconomic
position
adjusteda odds
ratio (95% CI)
Maternal
depression
adjusted odds
ratio (95% CI)b
Family structure
adjustedc odds
ratio (95% CI)
Maternal
smoking
adjustedd odds
ratio (95°o CI)
Fully adjustede
odds ratio (95%
CI)
1.64 (1.21, 2.23)
1.56 (1.15, 2.11)
1.49 (1.07, 2.07)
1.42 (1.05, 1.92)
1.27 (0.91, 1.78)
1.86 (1.50, 2.29)
1.75 (1.41, 2.17)
1.78 (1.44, 2.21)
1.53 (1.21, 1.93)
1.64 (1.33, 2.04)
1.37 (1.07, 1.74)
1.66 (1.19, 2.27)
1.52 (1.09, 2.11)
1.58 (1.15, 2.19)
1.48 (1.03, 2.11)
1.43 (1.03, 1.98)
1.28 (0.90, 1.84)
1.72 (1.36, 2.18)
1.61 (1.27, 2.06)
1.64 (1.29, 2.09)
1.52 (1.17, 1.98)
1.55 (1.22. 1.98)
1.35 (1.04, 1.76)
1.54 (1.09, 2.18)
1.55 (1.09, 2.22)
1.51 (1.06, 2.14)
1.62 (1.09, 2.40)
1.43 (1.00, 2.04)
1.54 (1.03, 2.30)
2.11 (1.42, 3.15)
1.86 (1.23, 2.81)
1.97 (1.31, 2.95)
1.62 (1.04, 2.54)
1.60 (1.06, 2.40)
1.26 (0.80, 1.98)
1.67 (1.13, 2.48)
1.53 (1.03, 2.30)
1.62 (1.09, 2.41)
1.34 (0.87, 2.08)
1.46 (0.98, 2.18)
1.19 (0.77, 1.86)
1.63 (1.07, 2.48)
1.62 (1.06, 2.48)
1.58 (1.04, 2.42)
1.80 (1.13, 2.86)
1.64 (1.07, 2.51)
1.77 (1.10, 2.83)
Participants with complete data on all variables included in table N = 440 offspring to mothers who were 18 years when pregnant, N = 4536 offspring of mothers who were
over 18 years when pregnant (total = 4976).
a
Adjusted for gestational age at first antenatal clinic visit and family income during year of pregnancy, family income during 14th year of child’s life, maternal education,
living in a problem residential area during 14th year of child’s life.
b
Adjusted for gestational age at first antenatal clinic visit and maternal post-natal depression and maternal depression when the child was aged 14.
c
Adjusted for gestational age at first antenatal clinic visit and marital status of mother during year of pregnancy, marital status of mother during child’s 14th year, whether
mother was living with biological father when child was aged 14.
d
Adjusted for gestational age at first antenatal clinic visit and maternal smoking when child was age 14 years.
e
Adjusted for gestational age at first antenatal clinic visit and all variables listed in a—d above.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Discussion
We have found that the 14 year old offspring of mothers who were aged 18 years and
younger compared to those who were offspring of older mothers were more likely to
have disturbed psychological behaviour, had poorer school performance, poorer
reading ability (assessed by WRAT3), were more likely to have been in contact with
the criminal justice system and were more likely to smoke regularly and to consume
alcohol. However, maternal age was not associated with health outcomes in the
offspring at age 14 years. Indicators of low socioeconomic position and maternal
depression were also associated with poorer psychological, cognitive and behavioural
outcomes among 14 year olds, and in addition children from poorer socioeconomic
backgrounds and whose mothers were depressed were more likely to have selfreported poor health, asthma, to have been admitted to hospital twice or more since
birth and to be bed-wetters at age 14. The associations between maternal age and
psychological distress, school performance, and smoking and alcohol use were all
largely explained by socioeconomic factors, maternal depression, family structure and
maternal smoking, with family structure and maternal smoking having particularly
marked effects on the attenuation of these associations. Maternal depression and
smoking may both be indicators of maternal psychological distress and difficulties
with coping. The importance of the family structure variable could reflect beneficial
effects of some factors such as the degree of stability within the home, the (constancy)
support (and contact) available to the mother and her offspring from having a partner
and/or negative effects associated with the practicalities of coping as a lone parent on
a day-today basis. The effect of support on outcomes for the offspring of teenage
mothers is an important area for further detailed work.
The large attenuation, with full adjustment, in the association between maternal age
and problems with the criminal justice system at age 14 suggests that any remaining
association may be explained by residual confounding. The increased odds of low
cognitive ability as assessed by the WRAT3 reading score was not however explained
by confounding by socioeconomic or other factors. Likewise, among children born to
young mothers, having a large number of fillings was not explained by confounding
by socioeconomic or other factors. Childhood cognitive ability is affected by preschool stimulation in and outside of the family home (Ramey & Ramey, 2004) and it
is plausible that both young maternal age and low socioeconomic position would both
independently affect stimulation and cognitive ability. The link between
socioeconomic position and dental caries is well established and is likely to reflect a
combination of intergenerational biological factors, lack of material resources to fund
adequate care and parental skills and knowledge (Peres et al., 2005). The fact that
dental services in Queensland are not publicly funded and are expensive may play a
role here. The independent effect of maternal age may be related to poorer parenting
skills among younger mothers, but this requires further investigation.
Study strengths and limitations
A major strength of this study is the large sample size and very detailed assessment of
childhood psychological, cognitive and behavioural outcomes. The follow-up of 73%
is high and consistent with other similar prospective birth cohorts (Golding, Pembrey,
& Jones, 2001). However, those children who were not seen at age 14 years were
more likely to have had teenage mothers and to be from poorer socioeconomic
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
backgrounds. Our results would only be biased if the associations that we have found
were either non-existent or in the opposite direction to those presented here. Whilst,
we cannot ascertain whether this is the case it seems unlikely. Further, recent detailed
mathematical modelling with the aim of predicting bias in a relative risk estimates in
this cohort would suggest that any effects of loss to follow-up would mean that the
results we present here are an underestimate rather than over estimate of the true
effects (Najman et al., 2005). This would include the effects of maternal age,
socioeconomic factors, family structure and other maternal characteristics on our
outcomes. Other limitations include the fact we are relying on self-report data, for
school performance and health status, although indicators of self-reported health are
widely used with children and adolescents they have rarely been validated (National
Centre for Health Outcomes Development, 2001). One inherent problem with
longitudinal studies is that by the time the long-term results can be seen, the social
conditions which produced them may have changed.
Conclusion
This particular study is distinguished from previous work on this topic by the length
of follow-up (few previous studies have been able to follow offspring to the age of
14), by the wide range of data collected, and by the consideration of a range of
confounding factors. The results presented here are similar to those reported from
other studies, most of which have focused on health outcomes in the perinatal period,
in that a range of ‘adverse outcomes’ are found for the offspring (at age 14 years) of
teenage mothers compared to older mothers, but, when adequate adjustment is made
for socioeconomic factors and other indicators of social circumstances much of the
effect of young maternal age disappears (depending on the particular outcome
studied). Two notable exceptions to this were the increased odds of low cognitive
ability and a large number of dental fillings that were affected independently by
maternal age, socioeconomic position, family structure and other maternal
characteristics. We find it particularly curious, however, given that in many contexts
policies directed at reducing rates of teenage pregnancy are situated within health
policy, that the only health outcome that remains associated with teenage motherhood
is dental health.
Moreover, as both Cunnington (2001) and also Fergusson and Woodward (1999)
point out, these findings confirm that not all teenage mothers and their offspring have
adverse outcomes, and that many if not the majority have good outcomes. For
example, while 13.9% of the offspring of teenage mothers in this study were
delinquent on the YSR compared to 7.9% of the offspring of older mothers, this
means that 86.1% of the offspring of teenage mothers were not delinquent. Yet
studies, and policies, which focus on the negative outcomes for young parents run the
risk of stigmatising all such parents and their offspring, thereby contributing to the
negative outcomes which they seek to redress.
Interestingly, many research papers and policy documents link teenage pregnancy
with conditions of deprivation, either before pregnancy or in subsequent parenthood,
and some recognise the primary role of socioeconomic position over young age as we
have demonstrated for a range of outcomes here. However, policies tend to focus on
maternal age and reducing the number of births to teenagers, rather than on addressing
poverty. Our results suggest that interventions aimed at reducing maternal poverty and
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
increasing support among those from the most deprived backgrounds may be more
effective ways of improving childhood psychological, cognitive, behavioural and
health outcomes than would interventions aimed solely at reducing rates of teenage
pregnancy and parenthood. Our results suggest that support for teenage mothers may
be particularly important for improving the outcomes in their children as they enter
adolescence. In future work we plan to investigate in more detail the effect of family
and social support and of changing socioeconomic position and social circumstances
on a range of outcomes, thereby more fully exploiting the longitudinal nature of this
unique resource.
Acknowledgements
The authors thank the Mater-University of Queensland Study of Pregnancy (MUSP)
Team, MUSP participants, the Mater Misericordiae Hospital and the Schools of
Social Science, Population Health, and Medicine, at The University of Queensland for
their support. Funding The MUSP is funded by National Health and Medical
Research Council (NHMRC), Queensland Health, the Centre for Accident Research
and Road Safety Queensland (CARRS-Q), and the Australian Institute of
Criminology (AIC). DAL is funded by a UK Department of Health Career Scientist
Award. MS is funded by the South West Public Health Observatory. The views
expressed in this publication are those of the authors and not necessarily those of any
funding bodies.
References
Achenbach, T. (1991). Integrative guide for the 1991 CBCL/4-18, YSR, and TRF
profiles. Burlington: University of Vermont Department of Psychiatry.
Australian Bureau of Statistics. (2000). Teenage fertility, in births Australia. Cat.
3301.0, Canberra.
Australian Bureau of Statistics. (2004). Year book Australia: Population, births.
Canberra.
Batty, G., & Deary, I. (2004). Early life intelligence and adult health. British Medical
Journal, 329, 585—586.
Bedford, A., & Foulds, G. (1978). Delusions—symptoms—states inventory state of
anxiety and depression (manual). Berkshire: NFER Publishing.
Berthoud, R. & Robson, K. (2001). The outcomes of teenage motherhood in Europe.
Innocenti working paper No.86. Florence: Innocenti Research Centre.
Bonell, C. (2004). Why is teenage pregnancy conceptualized as a social problem? A
review of quantitative research from the USA and UK. Culture, Health &
Sexuality, 6(3), 255—272.
Coory, M. (2000). Trends in birth rates for teenagers in Queensland, 1988 to 1997:
And analysis by economic disadvantage and geographic remoteness. Australia
and New Zealand Journal of Public Health, 24(3), 316—319.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Cunnington, A. (2001). What’s so bad about teenage pregnancy? The Journal of
Family Planning and Reproductive Health Care, 27, 36—41.
de Lemos, M. (1989). Standard progressive matrices, Australian manual. Victoria:
The Australian Education Council for Research.
Department of Health. (1992). The health of the Nation: A strategy for health in
England. HMSO: London.
Ermisch, J. & Pevalin, D. (2003a). Does a ‘teen-birth’ have longer- term impacts on
the mother? Evidence from the 1970 British Cohort study. Institute for Social
and Economic Research, Working Paper No. 2003-28. Colchester: University
of Essex.
Ermisch, J. & Pevalin, D. (2003b). Who has a child as a teenager? Institute for Social
and Economic Research. Working Paper No. 2003-30. Colchester: University
of Essex.
Evans, A. (2001). The influence of significant others on Australian teenagers’
decisions about pregnancy resolution. Family Planning Perspectives, 33(5),
224—230.
Fergusson, D., & Woodward, L. (1999). Maternal age and educational and
psychosocial outcomes in early adulthood. Journal of Child and Psychology
and Psychiatry, 43(3), 479—489.
Fraser, A., Brockert, J., & Ward, R. (1995). Association of young maternal age with
adverse reproductive outcomes. New England Journal of Medicine, 332(17),
1113—1117.
Furstenburg, F., Levine, J., & Brooks-Gunn, J. (1990). The children of teenage
mothers: Patterns of early childbearing in two generations. Family Planning
Perspectives, 22(2), 54—61.
Geronimus, A. (2003). Damned if you do: Culture, identity, privilege, and teenage
childbearing in the United States. Social Science & Medicine, 57(5), 88 1—
893.
Golding, J., Pembrey, M., & Jones, R. (2001). ALSPAG—the Avon longitudinal
study of parents and children. I. Study methodology. Paediatric & Perinatal
Epidemiology, 15, 74—8 7.
Health Development Agency. (2005). Teenage pregnancy and health scrutiny: A
briefing paper. Wetherby, Yorkshire: Health Development Agency.
Hobcraft, J., & Kiernan, K. (2001). Childhood poverty, early motherhood and adult
social exclusion. British Journal of Sociology, 52(3), 495—5 17.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
Hofferth, S., & Reid, L. (2002). Early childbearing and children’s achievement and
behavior over time. Perspectives on Sexual and Reproductive Health, 34(1),
41—49.
Hofferth, S., Reid, L., & Mott, F. (2001). The effects of early childbearing on
schooling over time. Family Planning Perspectives, 33(6), 259—267.
Jefferis, B., Power, C., & Hertzman, C. (2002). Birth-weight. childhood
socioeconomic environment, and cognitive development in the 1958 British
birth cohort study. British Medical Journal, 325, 304—305.
Kahn, J., & Anderson, K. (1992). Intergenerational patterns of teenage fertility.
Demography, 29(1), 39—57.
Keeping, J., Najman, J., Morrison, J., Western, J., Andersen, M., & Williams, G.
(1989). A prospective longitudinal study of social, psychological and obstetric
factors in pregnancy: Response rates and demographic characteristics of the
8556 respondents. British Journal of Obstetrics and Gynaecology, 96(3),
289—297.
Klepinger, D., Lundberg, S., & Plotnick, R. (1995). Adolescent fertility and the
educational attainment of young women. Family Planning Perspectives, 27,
23—28.
Lawlor, D., Davey Smith, G., & Ebrahim, S. (2004). The association of childhood
socioeconomic position with CHD risk in post-menopausal women: Findings
from the British women’s heart and health study. American Journal of Public
Health, 94, 1386—1392.
Lawlor, D., Ronalds, G., Clark, H., Davey Smith, G., & Leon, D. (2005). Birthweight
is inversely associated with incident coronary heart disease and stroke among
individuals born in the 1950s: Findings from the Aberdeen children of the
1950s prospective cohort study. Circulation, 112, 1414—1418.
Lawlor, D., & Shaw, M. (2002). Too much too young? Teenage pregnancy is not a
public health problem. International Journal of Epidemiology, 3], 552—554.
Najman, J., Andersen, J., Bor, W., O’Callaghan, M., & Williams, G. (2000). Postnatal
depression myth and reality: Maternal depression before and after the birth of
a child. Social Psychiatry & Psychiatric’ Epidemiology, 35, 19—27.
Najman, J., Bor, W., O’Callaghan, M., Williams, G., Aird, R., & Shuttlewood, G.
(2005). Cohort Profile: The Mater University of Queensland Study of
Pregnancy (MUSP). International Journal of Epidemiology, 34(5), 992—997.
Najman, J., Williams, G., Nikles, J., Spence, S., Bor, W., O’Callaghan, M., et al.
(2001). Bias influencing maternal reports of child behaviour and emotional
state. Social Psychiatry and Psychiatric Epidemiology, 36(4), 186—194.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
National Centre for Health Outcomes Development. (2001). Patient-assessed health
outcomes programme Instruments for children and adolescents: A review.
Report to the Department of Health.
McCulloch, A. (2001). Teenage childbearing in Great Britain and the spatial
concentration of poverty households. Journal of Epidemiology and
Community Health, 55, 16—23.
McLeod, A. (2001). Changing patterns of teenage pregnancy: Population based study
of small areas. British Medical Journal, 323, 199—203.
Mishra, S. (1981). Reliability and validity of the WRAT with Mexican—American
children. Psychology in the Schools, 18, 154—158.
O’Callaghan, M., Williams, G., Andersen. M., Bor, W., & Najman, J. (1995). Social
and biological risk factors for mild and borderline impairment of language
comprehension in a cohort of five-year-old children. Developmental Medicine
& Child Neurology, 37, 1051—1061.
Office for National Statistics. (1997). Underlying causes of death. Series DH2 No. 24.
London: HMSO.
Olausson, P., Haglund, B., Weitoft, G., & Cnattingius, S. (2001). Teenage
childbearing and long-term socioeconomic consequences: A case study in
Sweden. Family Planning Perspectives, 33(2), 70—74.
Peres, A., de Oliveira Latorre, M., Sheiham, A., Peres, K., Barros, F., Hernandez, P.,
et al. (2005). Social and biological early life influences on severity of dental
caries in children aged 6 years. Community Dentistry and Oral Epidemiology,
33(1), 53—63.
Pevalin, D. (2003). Outcomes in childhood and adulthood by mother’s age at birth:
Evidence from the 1970 British cohort study. Working paper 2003-31, ISER,
University of Essez, Colchester.
Quinlivan, J., Tan, L., Steel, A., & Black, K. (2004). Impact of demographic factors,
early family relationships and depressive symptomatology in teenage
pregnancy. Australian and New Zealand Journal of Psychiatry, 38, 197—203.
Ramey, C., & Ramey, 5. (2004). Early learning and school readiness: Can early
intervention make a difference? Merrill- Palmer Quarterly Journal of
Developmental Psychology, 50, 471—491.
Richards, M., Hardy, R., & Kuh, D. (2001). Wadsworth ME. Birth-weight and
cognitive function in the British 1946 birth cohort: Longitudinal population
based study. Brirish Medical Journal, 322, 199—203.
Social Exclusion Unit. (1999). Teenage pregnancy. London: HMSO.
doi: 10. l016/j.socscimed.2005. 10.007
Social Science and Medicine 62: 2526-2539
UNICEF. (2001). A league table of teenage births in rich nations. Innocenti report
card issue No. 3. UNICEF. Florence: Innocenti Research Centre.
Van der Klis, K., Westenburg, L., Chan, A., Dekker, G., & Keane, R. (2002). Teenage
pregnancy: Trends, characteristics and outcomes in South Australia and
Australia. Australia and New Zealand Journal of Public Health, 26(2), 125—
131.
Wilkinson, G. (1993). Wide range achievement test (WRA T3) administration manual.
Wilmington, DE: Wide Range, Inc.
Woodward, C., Santa-Barbara, J., & Roberts, R. (1975). Test—retest reliability of the
wide range achievement test. Journal of Clinical Psychology, 31(1), 8 1—84.