Energy and Weight Gain in
Pregnancy
2012
Energy Requirements in
Pregnancy
• Increased energy costs in pregnancy:
– increased maternal metabolic rate
– fetal tissues
– increase in maternal tissues
DRI for Energy in Pregnancy 2002
Estimated Energy Requirement
• Average dietary energy intake that is predicted
to maintain energy balance in a healthy adult of
a defined age, gender, weight, height, level of
physical activity consistent with good health.
• In children, pregnant and lactating women the
EER is taken to include the needs associated
with deposition of tissues or secretion of milk
BEE: Basal Energy
Expenditure
• BEE = energy consumed while at rest and
fasting
• In pregnancy BEE increases due to
metabolic contribution of uterus and fetus
and increased work of heart and lungs.
• Variable for individuals
Growth of Maternal and Fetal
Tissues
• Calculations Based on:
– Hytten
– IOM weight gain recommendations
T1 and T2 ~ 180 kcal per day
Longitudinal Data from DLW
Database
• Median TEE (total energy expenditure)
change from non-pregnant was 8
kcal/gestational week.
• TEE changes little in first trimester.
Variations in Energy
Requirements
• Body size - especially lbm
• Activity:
– most women decrease activity in last months
of pregnancy if they can
– increased energy cost of moving heavier body
• BMR
– rises in well nourished women (27%)
– rises less or not at all in women who are not
well nourished
• -Diet Induced Thermogenesis?
Evidence of energy sparing in Gambian women
during pregnancy: a longitudinal study using
whole-body calorimetry (AJCN, 1993)
• N=58, initially recruited, ages 18-40
– 25 became pregnant
– 21 participated in study protocols
– 9 completed BMR and 24 hour energy
expenditure
– 12 completed BMR
• Adjusted for seasonality, weight loss
expected during wet season
Poppitt et al., cont.
• Mean maternal prepregnancy weight was
52 kg
• Mean prepregnancy BMI was 21.2 + 2
• Mean birthweight was 3.0 + 0.1
• Mean gestational length was 39.4
• Mean weight gain was 6.8 kg
• Mean fat gain was 2.0 kg at 36 weeks
Poppitt et al., cont.
• BMR fell in early pregnancy
• Values per kg lbm remained below
baseline for duration of pregnancy
• Individual variation was high
Poppitt et al., cont.
• Energy sparing mechanisms may act via a
suppression of metabolism in women on
habitually low intakes.
• This maintains positive balance in the
mother and protects the fetus from growth
retardation
Prentice and Goldberg. Energy
Adaptations in human pregnancy:
limits and long-term consequences.
Am J Clin Nutr.
2000;71(supple):1226S-32S.
Longitudinal assessment of energy
balance in well-nourished, pregnant
women
(Koop-Hoolihan et al, AJCN, 1999)
• N=16, SF area
– 10 became pregnant
• BMI range was 19-26
• Mean weight gain at 36 weeks was 11.6 +
4 kg
• Mean birth weight was 3.6 kg
Koop-Hoolihan, cont
• Protocol: 5 times before pregnancy, 3 times during,
once 4-6 weeks postpartum
– RMR (resting metabolic rate/metabolic cart)
– DIT (diet induced thermogenesis/metabolic cart)
– TEE (total energy expenditure/doubly labeled
water)
– AEE (activity energy expenditure/difference
between TEE and RMR)
– EI (energy intake/3 day food records)
– Body composition - densitometry, tbw, bmc with
absorptiometry
Koop-Hoolihan, cont
• Women with the largest cumulative
increase in RMR deposited the least fat
mass (this was the only prepregnant
factor that predicted fat mass gain)
• In all indices there was large individual
variation
• Average total energy cost of pregnancy
was similar to work of Hytten and Leitch
(1971)
• Food intake records indicated 9%
increase in kcals with pregnancy, but
highly variable
Weight Gain in Pregnancy
• Components & patterns
• IOM recommendations
– 1990
– 2009
Components of Weight Gain
Patterns of Maternal Fat Accretion
Maternal Weight Gain
Number Included
Year in Analysis
< Ideal > Ideal
%
%
2009
917,032
21.2
48.2
2007
920,893
21.4
48.6
2005
661,128
22.2
48.9
2003
594,311
21.7
49.6
2001
555,537
22.4
48.6
1999
505,065
24.8
46.5
1997
410,959
30.9
40.8
1995
363,959
27.6
42.6
1993
209,074
28.6
40.3
1991
110,404
29.3
41.0
1990
118,301
30.6
40.6
1989
104,119
32.1
36.9
1988
17,681
33.0
37.4
National Pregnancy
Nutrition Surveillance
http://www.cdc.gov/pe
dnss/pnss_tables/htm
l/pnss_national_table
16.htm
Percent of Women Gaining <7.3 kg
37-39
weeks
40
weeks
Non-Hispanic
Black
15.5
14.0
Hispanic
12.4
11.2
Non-Hispanic
White
8.8
8.0
All US
10.4
9.3
Hicky, CA. Am J Clin Nutr. 2000;71(supple):1364S-70S.
Characteristics of Women Associated
with Inadequate Weight Gain
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•
•
•
•
•
•
Lower education levels
Unmarried
Aged > 30 years
Smoking
Multiple parity
Unintended pregnancy
Psychosocial characteristics such as attitude
toward weight gain, social support, depression,
stress, anxiety, and self-efficacy.
Hicky, CA. Am J Clin Nutr. 2000;71(supple):1364S-70S.
1990 IOM Recommendations
Institute of Medicine. Nutrition during pregnancy, weight
gain and nutrient supplements. Report of the
Subcommittee on Nutritional Status and Weight Gain
during Pregnancy, Subcommittee on Dietary Intake and
Nutrient Supplements during Pregnancy, Committee on
Nutritional Status during Pregnancy and Lactation, Food
and Nutrition Board. Washington, DC: National Academy
Press, 1990
Cogswell M, Serdula M, Hungerford D, Yip R. Gestational weight
gain among average-weight and overweight women—what is
excessive? Am J Obstet Gynecol 1995;172:705–12
1990: Recommended total weight gain in
pregnant women by prepregnancy BMI (in
kg/m2)
Weight-for-height category Recommended total gain (kg)
Low (BMI <19.8)
12.5–18
Normal (BMI 19.8–26.0)
11.5–16
High (BMI >26.0–29.0)2
7–11.5
Adolescents and black women should strive for gains at the upper end of
the recommended range. Short women (<157 cm) should strive for gains
at the lower end of the range. The recommended target weight gain for
obese women (BMI >29.0) is 6.0.
Incidence of adverse outcomes for 6690
pregnancies in San Francisco
Parker J, Abrams B. Prenatal weight gain advice: an examination
of the recent prenatal weight gain recommendations of the
Institute of Medicine. Obstet Gynecol 1992;79:664–9
Percentage of US women with normal prepregnancy
weights who retained >9 kg 10–24 mo postpartum relative
to prepregnancy weight
(Parker J, Abrams B. Differences in postpartum weight retention between black and
white mothers. Obstet Gynecol 1993;81:768–74)
Percentage of US Women Who Gained
>40 pounds during pregnancy
(MMWR, February 2008)
(source = birth certificates; singleton delivery only)
Prepregnancy Obesity*
Washington State,1992-2005
12
11.4
10
Percent
8
6
5.3
4
1.3
2
0.3
0
1992
1993
1994
1995
1996
1997
Obesity
*Obesity
1998
1999 2000 2001 2002 2003 2004 2005
Morbid Obesity
is defined as prepregnancy weight > 200 lbs
Morbid obesity is defined as prepregnancy weight > 275 lbs
Obesity by Parity and Race/Ethnicity
Percent Obese (BMI> 30)
Washington State, 2003-2005
45
40
35
30
25
20
15
10
5
0
39
35
29
28
24
24
19
16
13
9
Hispanic
White
African
American
Primiparous
American
Indian
Multiparous
Asian/PI
Weight Gain During Pregnancy:
Reexamining the Guidelines (IOM, 2009)
•
•
•
•
•
•
•
•
New Guidelines
Conceptual Framework
Composition and Components of Weight Gain
Determinants of Weight Gain
Maternal Consequences of Weight Gain
Child Consequences of Weight Gain
Determining Optimal Weight Gain
Achieving Recommendations
2009 Guidelines for Specific
Populations
Women of
Short Stature
“unable to identify evidence sufficient to continue to
support a modification of GWG guidelines”
Pregnant
Adolescents
“unable to identify evidence sufficient to continue to
support a modification of GWG guidelines”
Racial or
Ethnic Groups
“Recommendations should be generally applicable to
the various racial or ethnic subgroups”
Women with
Multiple
Fetuses
Provisional Guidelines for Twins (at term):
Obesity
Classes II and
III
Insufficient evidence to develop more specific
recommendations.
–Underweight: insufficient evidence
–Normal Weight: 17-25 kg
–Overweight : 14-23 kg
–Obese: 11-19 kg
Determinants of Gestational Weight Gain
Determinants: Social & Policy Findings
Health
Services
Evidence for influence is weak; advice missing,
inconsistent, erroneous
Community “neighborhood environments can influence GWG
by providing access to healthy foods and
opportunities for PA”
Family
Married women more likely to gain within
guidelines; association between partner violence
and insufficient GWG; family support associated
with good GWG
SES
Interactive and confounding effects; food insecurity
in obese women associated with high GWG
Determinants: Genetics
• Maternal: insufficient evidence
• Fetal: GWG associated with birthweight; preliminary
conclusions about fetal genotype and birthweight:
(a) there is a fetal genotype effect on weight at birth (about 30
percent of the adjusted variance)
(b) both parents’ genes influence birth weight with a stronger effect
for maternal genes
(c) specific allelic variants have been associated with weight at
birth
(d) mutations in GCK and HNF1β are associated with low birth
weight
(e) mutations in HNF4α are associated with high birth weight
(f) a few quantitative trait loci on chromosomes 6, 10, and 11 have
been uncovered from genome-wide linkage scans
Determinants: Maternal Factors
Pregravid BMI
Depression
In general GWG decreases as
BMI increases; but large
variation
Mild n/v no adverse effect; HG
lower GWG
AN: variable
BN: greater GWG
Both low and high GWG
Stress
Low GWG
Hyperemesis
Gravidarum
Disordered
Eating
Determinants: Maternal Behaviors
Diet
Relationship between energy intake and
GWG; insufficient evidence for diet
composition and GWG
Physical Inverse relationship between PA and
Activity GWG
Tobacco “Limited” evidence for inverse
association with GWG; smoking has
independent effect on birth weight.
“There remains a lack of information to relate dietary intake or physical activity
to GWG even though they are primary determinants of weigh gain in nonpregnant individuals.”
Consequences of GWG for Mother
• Strong association between high GWG &:
– increased risk of cesarean delivery
– postpartum weight retention (3 mos to 3 yr)
• Modest association:
– failure to initiate breastfeeding
• Inconclusive evidence:
– pregnancy complications like glucose intolerance and
gestational hypertensive disorders
– long term health consequences
Consequences of GWG for Child
• Studies consistently show linear relationship
between GWG and birthweight for gestational
age.
• Some, but limited evidence for associations
between GWG and:
–
–
–
–
–
Still birth
Preterm birth (at both low and high GWG)
Childhood asthma and low GWG
High GWG and some cancers and ADHD
High GWG and childhood obesity
Recent Studies on Impact of GWG
on Offspring Obesity
Zilko et al. Am J
Obset Gynecol, 2010
In NLSY: GWG associated with child
overweight
Mamun et al.
Circulation, 2009
In Australian cohort : Greater GWG associated
with greater offspring BMI in early adulthood
Von Kries et al.
Int J Pediatr Obes,
2010
Large German cross-sectional study: higher
than average GWG accounts for moderate
increase in offspring overweight at ages 3-17
Beyerlein et al. PLoS
One. 2012; 7(3):
e33205
Combined data from 3 large German cohorts:
In adjusted models, positive associations of
total and excessive GWG with mean BMI SDS
and overweight were observed only in children
of non- overweight mothers
Determining Optimal Weight Gain
• “Evidence is remarkably clear that
prepregnant BMI is an independent
predictor of many adverse outcomes of
pregnancy.”
• Limited data to link GWG to health
outcomes of mothers and children after
the neonatal period.
Approaches to Achieving
Recommendations
Comparison of Recommended
Weight Gain & Actual Outcomes
IOM States that full implementation
of guidelines would mean:
• Preconceptual services offered to all
overweight & obese women to help them
reach a healthy weight before conceiving
• Offering services, such as counseling on
diet and PA during pregnancy to all
pregnant women.
• Offering services to all postpartum women
5 Action Recommendations
1.
2.
3.
4.
5.
DHHS conduct routine surveillance of GWG and
postpartum weight retention
All states adopt revised version of birth certificate that
includes maternal pp weight, height, weight at delivery,
gestational age at last measured weight (and strive for
100% completion of fields).
Fed/state/local agencies and health care providers
inform women of importance of conceiving at a normal
BMI
Agencies/organizations adopt new guidelines and
publicize to members and women
Providers of prenatal care should offer counseling on
dietary intake and PA that is tailored to life
circumstances.