Chapter 2 The Course of Prenatal Development
Fertilization to birth
Prenatal development lasts approximately 266 days
Three periods
Germinal
Embryonic
Fetal
The Germinal Period
First two weeks after conception
Creation of the fertilized egg (the zygote)
Cell division
Attachment of the zygote to the uterine wall
Blastocyst -- consists of an inner mass of cells that will eventually develop into the embryo
Trophoblast -- outer layer of cells that later provides nutrition and support for the embryo
Implantation -- the attachment of the zygote to the uterine wall
takes place about 10 to 14 days after conception
The Embryonic Period
Occurs from two to eight weeks after conception
Rate of cell differentiation intensifies
Begins as the blastocyst attaches to the uterine wall
Every body part eventually develops from these three layers
endoderm
ectoderm
mesoderm
The mass of cells is an embryo
Organogenesis -- the process of organ formation during the first two months of prenatal
development
organs are especially vulnerable to environmental influences
Life-support systems for the embryo develop rapidly
Life-Support Systems for the Embryo
Amnion -- bag containing a clear fluid in which the developing embryo floats
Umbilical cord contains two arteries and one vein and connects the baby to the placenta
Placenta consists of a disk-shaped group of tissues in which small blood vessels from the mother
and the offspring intertwine but do not join
The Fetal Period
Fetal period begins two months after conception and lasts for seven months
Three months after conception -- fetus is about 3 inches long; weighs about 3 ounces
By the end of the fifth month, the fetus is about 12 inches long and weighs close to a pound
At birth, the average American baby weighs 7½ pounds and is about 20 inches long
Three Trimesters
The germinal and embryonic periods occur in the first trimester
The fetal period begins toward the end of the first trimester and continues through the second and
third trimesters
Viability (the chances of surviving outside the womb) occurs at the beginning of the third trimester
About 24-25 weeks after conception
The Brain
By the time babies are born, they have approximately 100 billion neurons
The basic architecture of the brain is assembled during the first two trimesters
The third trimester and the first two years of postnatal life are characterized by connectivity and
functioning of neurons
The neural tube develops out of the ectoderm and forms at about 18 to 24 days after conception
Two birth defects related to the failure of the neural tube to close are:
Anencephaly
Spina bifida
Folic acid may prevent neural tube defects
The generation of new neurons is called neurogenesis
Neuronal migration occurs at 6-24 weeks after conception
At about the 23rd prenatal week, connections between neurons begin to form
Prenatal Tests
Ultrasound sonography
non-invasive
high-frequency sound waves
Fetal MRI
Used to obtain more detailed images than ultrasound
Chorionic villus sampling (CVS)
tiny tissue sample from the placenta is removed and analyzed
Amniocentesis
sample of amniotic fluid is withdrawn and tested for chromosome or metabolic disorders
Maternal blood screening
Identifies pregnancies that have an elevated risk for birth defects such as spina bifida and
Down syndrome
Triple Screen
Measures three substances in the mother’s blood
If abnormal, ultrasound is performed, then amniocentesis
Infertility and Reproductive Technology
Approximately 10-15 couples in the United States experience infertility
Defined as the inability to conceive a child after 12 months of regular intercourse without
conception
In vitro fertilization (IVF)
25 to 30 percent of pregnancies achieved by fertility treatments result in multiple births
Hazards to Prenatal Development
A teratogen is any agent that can potentially cause a birth defect or negatively alter cognitive and
behavioral outcomes
Drugs
Incompatible blood types
Environmental pollutants
Infectious diseases
Maternal stress, advanced maternal and paternal age
The dose, genetic susceptibility, and the time of exposure influence both the severity of damage to
an embryo or fetus and the type of defect
Prescription drugs
Antibiotics
Antidepressants
Hormones
Accutane
Psychoactive drugs
Caffeine
Alcohol (Fetal alcohol spectrum disorders, FASD)
Nicotine
Cocaine
Methamphetamine
Marijuana
Heroin
Incompatible blood types
Difference in blood groups -- A, B, O, and AB
Rh factor
Environmental hazards
Toxic wastes
X-ray radiation
Maternal diseases
Rubella
Syphilis, genital herpes, HIV/AIDS
Diabetes
Other Parental Factors
Maternal diet and nutrition
Overweight before and during pregnancy
Folic acid is important for normal prenatal development
Eating fish -- mercury levels
Maternal age -- 35 years or older at risk
Emotional states and stress
Anxiety
Depression
Paternal factors
Smoking
Prenatal Care
Involves a defined schedule of visits for medical care
Provides screening for manageable conditions and treatable diseases
Includes comprehensive educational, social, and nutritional services
Centering Pregnancy is a new program that is relationship-centered and provides complete
prenatal care in a group setting.
Childbirth Setting and Attendants
In the United States, 99 percent of births take place in hospitals
Midwives
Practiced throughout the world
95 percent of the midwives who delivered babies in the United States were certified
nurse-midwives
Doulas
A caregiver who provides continuous physical, emotional, and educational support for the
mother before, during, and after childbirth
Methods of Childbirth
Medications
Three basic kinds of drugs
Analgesia
Anesthesia
Oxytocics
Natural and Prepared Childbirth
Natural childbirth -- reduce pain with breathing techniques and relaxation
Prepared childbirth -- a.k.a. Lamaze
Other Non-Medicated Techniques to Reduce Pain
Waterbirth -- giving birth in a tub of warm water
likely to be less stressful for the baby and the mother
Massage -- reduce pain and anxiety
Acupuncture -- insertion of strategically located needles
Breech or Cesarean Delivery
Breech position -- buttocks rather than head emerge first
Can prevent the baby from breathing normally
Cesarean delivery -- the baby is removed from the mother’s uterus through an incision made in her
abdomen
May be lifesaving but carries the risks of major surgery
Apgar Scale
Used to assess the health of newborns at one and five minutes after birth
A score, or reading, of 0, 1, or 2 on each of these five health signs
heart rate, respiratory effort, muscle tone, body color, and reflex irritability
Anoxia -- an insufficient supply of oxygen
Low Birth Weight and Preterm Infants
Low birth weight -- less than 5½ pounds at birth
Very low birth weight -- under 3 pounds
Extremely low birth weight -- under 2 pounds.
Preterm -- born three weeks or more before full term
Small-for-date -- birth weight is below normal when the length of the pregnancy is considered
Incidence and Causes of Low Birth Weight
Incidence of low birth weight varies considerably from country to country
Related to poverty, maternal health status, maternal nutrition
More health and developmental problems than normal-weight infants
At school age, more likely to have a learning disability, attention deficit hyperactivity
disorder, or breathing problems such as asthma
Nurturing Low Birth Weight and Preterm Infants
Kangaroo care -- a way of holding an infant so that there is skin-to-skin contact for two to three
hours per day over an extended time in early infancy
Massage therapy -- firm stroking with the palms of the hands three times per day for 15-minute
periods
Bonding -- formation of a connection, especially a physical bond, between parents and the
newborn in the period shortly after birth
The Postpartum Period
Postpartum period -- lasts for about six weeks after childbirth or delivery or until the mother’s
body has completed its adjustment and has returned to a nearly pre-pregnant state
Physical and psychological adjustments
Involution -- process by which the uterus returns to its pre-pregnant size
Emotional and Psychological Adjustments
Baby blues -- two to three days after birth, many women begin to feel depressed, anxious, and
upset
Postpartum depression -- a major depressive episode about four weeks after delivery
Fathers also undergo considerable adjustment in the postpartum period, even when they work
away from home all day
Postpartum Blues and Postpartum Depression Among U.S. Women
Pregnancy, Childbirth and Motherhood
Prenatal care
Pregnancy—9-month sickness
What do you know about pregnancy?
How is this information known?
Pregnancy normal and healthy, although occasionally
Physical Reactions During Pregnancy
Weight gain; Protrusion of abdomen
Breast tenderness
Frequent urination
Fatigue & nausea
Individual differences
Interest in Sexual activities
Research?
uncomfortable and inconvenient
Emotional Reactions During Pregnancy---great variation exists between women
Positive Emotions
wonder and awe—new growing person
married women—doing what they are “supposed to”
transition into adulthood—sense of accomplishment and purpose
sense of attachment
anticipation—find pleasure in looking forward to tasks of motherhood and child rearing—and a source of
satisfaction
Negative Emotions
change—emotions fragile and changing
depression, fears and anxieties
self-image and unattractive—culture that values slimness—woman’s self-image may deteriorate
loss of identity—now a “pregnant woman
health issues
Factors influencing a woman's response to pregnancy
physical reaction
planned pregnancy
relationship with baby's father
economic status
miscarriage-unintended termination of pregancy
Stressful events
Attitudes Toward Pregnant Women—pregnancy a public event
Situational factors—context shopper or apply for job
Hostile and benevolent sexism—pregnant women seen as fragile and dependent, less
threatening
Attitudes a function of where maternity clothes are located-- Maternity clothes and social status—high status
stores: femininity, privacy; low status stores: image of being fat with job to do
Research by Shelley Taylor and Ellen Langer 1977: pregnant or not in elevator
People tend to avoid standing close to pregnant women, men especially. Both looked furtively
looked at stomach
People likely to help a pregnant woman
Employment during pregnancy
Ethnic, class, and cultural differences—black women not expected to stay home full time;
developing countries often expected to work
Combining career and children—especially if college graduate
Typical Work Patterns
Employment during pregnancy does not endanger the health of the pregnant woman or the
baby
Factors Related to Premature Delivery:
physically demanding job
night shift
prolonged standing without a break
Emotional Reactions to Childbirth--Wide variation
Intense joy
Reactions to pain
Fathers' reactions—when participate in birth of child, experience intense joy
Motherhood
Images of mothers and motherhood----Is there a motherhood mystique?
Motherhood mandate
Stereotypes About Motherhood
Contradictory messages of happy fulfillment, perfect mothering, and evil force
Stereotype emphasizes that woman’s ultimate fulfillment achieved by becoming a mother
Short adjustment, then competent mother, devoted to family.
The Reality of Motherhood
Negative Factors
1. Child care is physically exhausting; sleep deprivation is also common.
2. Roughly 35% of infants in U.S. are born to unmarried women; mothers may not have adequate
income.
3. Fathers help much less with child rearing than mothers had expected.
4. For several weeks after childbirth, women report that they feel leaky and dirty, coping with
after-birth discharges. They are also likely to feel pain in the vaginal area, the uterus, and the
breasts.
5. New mothers seldom have training for the tasks of motherhood.
they often report feeling incompetent.
6. Babies cry much more than parents expect, and they do not smile until they are about 2 months old.
In reality, babies do not smile until they are about 2 months old; also, many babies are fussy, and they
resist cuddling.
7. Mothers of newborns may have little contact with other adults.
8. The woman’s romantic partner may feel neglected.
9. Women feel disappointed in themselves because they do not match the standards of the ideal
mother, the completely unselfish and perfect woman.
10. People frequently blame mothers—more than fathers—for most of the problems that infants and
children develop.
Infant Mortality
Positive factors:
Discovering a sense of strength—empowered, confident
Interactions with their children—intense loving interaction
Children can be fun and interesting
Look at world from new viewpoint
Develop new aspects of personality----Help parent develop an important part of own personality---ability to
nurture
When fathers participate and express admiration for their partners, marital satisfaction increases
Many mom’s state difficult to describe positive side, more abstract, more intense.
Motherhood and Women of Color-- Wide variation of customs across cultures
Stereotypes of Black mothers—Black welfare mother & Black superwoman
Extended families provide stabilizing influence in Black and Latina/o cultures
Continuity of generations emphasized in many North American Indian cultures
Lesbian Mothers
Diversity of situations
Diversity of situations
Lesbian mothers and heterosexual mothers have similar parenting styles.
Lesbian mom: children raised by lesbians are well adjusted, and do not differ substantially from
children raised by heterosexuals.
Differences found in gender stereotypes in children—because raised in less traditional setting.
Partners likely to equally share financial and family responsibilities.
Lesbian mothers and heterosexual mothers have similar parenting styles
Lesbian mothers are more likely to engage in imaginative play with their children and less likely to spank them.
Most children raised by lesbians are positive about their mothers' relationships
Custody and adoption
Breast Feeding
Education
Age
Ethnicity
Social support
Health benefits of breast feeding
Postpartum Disturbances Postpartum period
Postpartum blues (maternity blues)

short-lasting change in mood

usually occurs during first 10 days after childbirth

experienced by about half of new mothers

symptoms include crying, sadness, insomnia, irritability, anxiety, and feeling
overwhelmed
Postpartum depression (postnatal depression)

more serious disorder

symptoms include extreme sadness, fatigue, despair, low of interest in enjoyable
activities, and loss of interest in the baby

affects about 10% to 15% of women who have given birth

begins to develop within 6 months after childbirth

may last for many months
 similar to other kinds of depression
Social factors
stress
economic status
social support
No consistent relationship found between hormonal levels and postpartum disorders
Returning to the Workplace After Childbirth
Individual differences
Length of maternity leave not correlated with mental health measures except for women
who consider their employment an important part of their identity
Homemakers, women employed part time, and women employed full time have similar mental health
measures one year after childbirth.
Maternity/Family Leave Policies
Deciding Whether To Have Children
Attitudes Toward Women Choosing Not to Have Children
compulsory motherhood
child-free women rated as lower than women with children on fulfillment, happiness and having a
rewarding life
advice from friends and relatives
the number of children
Advantages and Disadvantages of Being Child-Free
Advantages of Being Child-Free:
1. Parenthood is an irrevocable decision., you can’t take children back to the store for a refund.
2. Some couples are afraid that they will not be good parents.
3. Parenthood is extremely stressful.
4. Some couples realize that they don't have the energy required to raise children.
5. Some couples realize that they genuinely do not enjoy children.
6. Some couples are reluctant to give up a satisfying and flexible lifestyle for a more child-centered
orientation.
7. Children can interfere with educational and vocational plans
8. Raising children can be extremely expensive.
9. People can spend time with other people's children, even if they don’t have children of their own.
10.Some couples do not want to bring children into a world threatened by overpopulation, nuclear war,
terrorism, and other serious global problems.
Reasons for having children
1 Parenthood offers a lifelong relationship of love, connection, nurturance, and social interactions with
other human beings, children can enrich people’s lives.
2. Parents have a unique chance to be responsible for someone’s education and training. in raising a child,
they can clarify their own values and instill them in their child.
3. Parents can watch their children grow into socially responsible adults and helpe the world become a
better place.
4. Parenthood is challenging, it offers people the opportunity to be creative and learn about own potential
5. Through parenting, people can fulfill their relationship with their spouse, and they can become a
“family.”
6. Children can be a source of fun, pleasure, and pride.
Infertility
10-15% of couples
Health and age factors
Fertile and infertile women do not differ in their marital satisfaction or self-esteem
Many different reactions
Infertile women report higher levels of distress and anxiety
Caught between hopefulness and mourning
Women of color, stereotypes, and racist health care providers
Medical treatments and reproductive technologies
Many women manage to refocus their lives when infertility seems likely