C H A P T E R 3 : P R E N ATA L
D E V E L O P M E N T A N D B I RT H
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Prenatal Development
 Conception occurs when a single sperm cell from the male unites with an ovum (egg)
 Prenatal development is divided into 3 periods and lasts approximately 266-280 days:
 Germinal period: first 2 weeks after conception, zygote created
 Embryonic period: occurs from 2 to 8 weeks after conception
 Fetal period: begins 2 months after conception and lasts until birth
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Prenatal Development
 Germinal Period: period of development that takes place the first two weeks after conception
 Rapid cell division by the zygote
 Blastocyst: group of cells after about 1 week
 Trophoblast: outer layer of cells that later provides nutrition and support for the embryo
 Implantation: attachment of the zygote to the uterine wall; occurs 10 to 14 days after conception
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Prenatal Development
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Prenatal Development
 Embryonic Period: development from 2 to 8 weeks after conception
 Begins when blastocyst attaches to uterine wall
 Mass of cells is now called an embryo
 Three layers of cells: endoderm, mesoderm, and ectoderm
 Amnion: a bag that contains a clear fluid (amniotic fluid) in which the embryo floats
 Umbilical Cord: connects the baby to the placenta
 Placenta: group of tissues containing mother and baby’s intertwined blood vessels
 Organogenesis: process of organ formation during the first two months of prenatal development
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Prenatal Development
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Prenatal Development
 Fetal Period: development from two months after conception to birth
 Rapid growth and change
 Viability: the age at which a fetus has a chance of surviving outside the womb
 Currently 24 weeks; changes with advances in medical technology
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Prenatal Development
 The Brain:
 Babies have approximately 100 billion neurons (nerve cells) at birth
 Architecture of the brain takes shape during the first two trimesters
 Increases in connectivity and functioning occur from the third trimester to 2 years of age
 Neural tube develops 18 to 24 days after conception
 Anencephaly
 Spina bifida
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Prenatal Development
 The Brain:
 Neurogenesis: the generation of new neurons
 Begins at fifth prenatal week and continues throughout prenatal period
 Neuronal migration: cells move outward from their point of origin to their appropriate locations
 Occurs approximately 6 to 24 weeks after conception
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Hazards to Prenatal Development
 Teratogen: any agent that can cause a birth defect or negatively alter cognitive and behavioral outcomes
 Drugs (prescription, nonprescription)
 Incompatible blood types
 Environmental pollutants
 Infectious diseases
 Nutritional deficiencies
 Maternal stress
 Advanced age of parent
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Hazards to Prenatal Development
 Severity of damage to the unborn depends on:
 Dose
 Genetic susceptibility
 Time of exposure
 Critical period: a fixed time period during which certain experiences or events can have a long-lasting effect on development
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Hazards to Prenatal Development
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Hazards to Prenatal Development
 Prescription and Non-prescription Drugs:
 Many women are given drugs while pregnant
 Some are safe; some can cause devastating birth defects
 Known prescription teratogens include antibiotics, some antidepressants, some hormones, and Accutane
 Non-prescription teratogens include aspirin and diet pills
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Hazards to Prenatal Development
 Psychoactive Drugs: drugs that act on the nervous system to alter states of consciousness, modify perceptions, and change moods
 Includes caffeine, alcohol, nicotine
 Caffeine:
 small risk of miscarriage and low birth weight for those consuming more than 150 mg. daily
 Increased risk of fetal death for those consuming more than 300 mg. daily
 FDA recommends not consuming caffeine or consuming it sparingly
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Hazards to Prenatal Development
 Alcohol:
 Fetal alcohol syndrome: abnormalities in newborn due to mother’s heavy use of alcohol in pregnancy
 Facial deformities
 Defective limbs, face, heart
 Most have below-average intelligence; some are mentally retarded
 Even light to moderate drinking during pregnancy has been associated with negative effects on the fetus
 FDA recommends no alcohol consumption during pregnancy
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Hazards to Prenatal Development

 Maternal smoking can negatively influence prenatal development, birth, and postnatal development
 Associated with:
 Preterm births and low birth weight
 Fetal and neonatal death
 Respiratory problems
 SIDS (sudden infant death syndrome)
 ADHD (attention deficit hyperactivity disorder)
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Hazards to Prenatal Development
 Illegal drugs that harm during pregnancy:
 Cocaine
 Methamphetamine
 Marijuana
 Heroin
 Incompatible blood types (Rh factor)

Can cause mother’s immune system to produce antibodies that will attack the fetus
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Hazards to Prenatal Development

 Radiation
 Environmental pollutants and toxic wastes

 Sexually transmitted diseases (syphilis, genital herpes,
AIDS)
 Rubella
 Diabetes
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Hazards to Prenatal Development





 Exposure to teratogens
 Paternal age
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Prenatal Care
 Prenatal care typically includes:
 Screening for manageable conditions and treatable diseases
 Medical care
 Educational, social, and nutritional services
 Centering Pregnancy: relationship-centered program
 Importance of prenatal care
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1990
2004
Percentage of U.S. Women Using Timely
Prenatal Care: 1990 to 2004
50
40
30
20
10
0
100
90
80
70
60
Non-Latino
White women
African
American women
Latino women
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The Birth Process
 Three stages of birth:
 Stage 1: uterine contractions begin at 15 to 20 minutes apart and last up to 1 minute, becoming closer and more intense with time
 Causes the cervix to stretch and open to about 10 cm

 This stage lasts an average of 12 to 14 hours
Stage 2: baby’s head begins to move through dilated cervix opening and eventually emerges from the mother’s body
 This stage lasts approximately 45 minutes
 Stage 3: umbilical cord, placenta, and other membranes are detached and expelled ( afterbirth)
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The Birth Process
 Childbirth Setting and Attendants:
 99% of deliveries take place in hospitals
 Home delivery or freestanding birth center
 Compared to doctors, midwives:
 Typically spend more time than doctors counseling and educating patients
 Provide more emotional support
 Are typically present during the entire labor and delivery process
 Doulas provide continuous physical, emotional, and educational support for mother before, during, and after childbirth
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Methods of Childbirth
 Key choices involve use of medication and when to have a cesarean delivery
 Typical pain medication:
 Analgesia: pain relief
 Anesthesia: blocks sensation in an area of the body
(can also block consciousness)
 Epidural block
 Oxytocics: synthetic hormones used to stimulate contractions
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Methods of Childbirth
 Natural childbirth: aims to reduce pain by decreasing fear and using breathing/relaxation techniques
 Prepared childbirth (Lamaze): special breathing techniques; education about anatomy and physiology
 Basic belief is that, when information and support are provided, women know how to give birth
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Methods of Childbirth
 Other natural techniques used to reduce pain:
 Waterbirth: giving birth in a tub of warm water
 Massage
 Acupuncture: insertion of very fine needles into specific locations in the body
 Hypnosis: the induction of a psychological state of altered attention and awareness
 Music therapy: utilizes music to reduce stress and manage pain
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Methods of Childbirth
 Cesarean Delivery: the baby is removed from the mother’s uterus through an incision made in the abdomen
 Often used if baby is in breech position or other complications arise
 Cesareans involve a higher infection rate, longer hospital stays, and a longer recovery time
 Rate of cesarean births has increased dramatically in recent years
 Better identification of complications
 Increase in overweight and obese mothers
 Extra caution by doctors to avoid lawsuits
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Transition from Fetus to Newborn
 Birth process is stressful for baby
 Anoxia: a condition in which the fetus has an insufficient supply of oxygen
 Baby secretes adrenaline and noradrenalin , hormones that are secreted in stressful circumstances
 Measuring neonatal health and responsiveness:
 Apgar Scale: assessed at 1 minute and 5 minutes after birth
 evaluates heart rate, body color, muscle tone, respiratory effort, and reflex irritability
 10 is highest, 3 or below indicates an emergency
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Transition from Fetus to Newborn
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Transition from Fetus to Newborn
 Measuring neonatal health and responsiveness:
 Brazelton Neonatal Behavioral Assessment Scale
(NBAS):
 Typically performed within 24–36 hours after birth

Assesses newborn’s neurological development, reflexes, and reactions to people and objects
 Low scores can indicate brain damage or other difficulties
 Neonatal Intensive Care Unit Network Neurobehavioral
Scale (NNNS):

Provides a more comprehensive analysis of newborn’s behavior, neurological and stress responses, and regulatory capacities

Assesses the “at-risk” infant
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Preterm and Low Birth Weight Infants


Preterm and Small-for-Date Infants:
 Low birth weight infants weigh less than 5 ½ lbs. at birth
 Preterm infants are those born three weeks or more before full term
 Small-for-date infants are those whose birth weight is below normal when the length of the pregnancy is considered
Rate of preterm births has increased
 Number of births to mothers 35 years and older
 Rates of multiple births
 Management of maternal and fetal conditions
 Substance abuse
 Stress
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Preterm and Low Birth Weight Infants
 Causes of low birth weight:
 Poor health and nutrition
 Cigarette smoking
 Adolescent births
 Use of drugs
 Multiple births/reproductive technology
 Improved technology and prenatal care
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Preterm and Low Birth Weight Infants
 Possible consequences:
 Language development delays
 Lower IQ scores
 Brain injury
 Lung or liver diseases
 More behavioral problems
 Learning disabilities
 ADHD
 Breathing problems (asthma)
 Approximately 50% are enrolled in special education programs
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Preterm and Low Birth Weight Infants
 Some effects can be improved with:
 Early speech therapy
 Intensive enrichment programs
 Kangaroo care, massage therapy, and breast feeding
 Kangaroo Care: treatment for preterm infants that involves skin to skin contact
 Massage: research conducted by Tiffany Field
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Preterm and Low Birth Weight Infants
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The Postpartum Period
 Postpartum period lasts about six weeks or until the mother’s body has completed its adjustment and has returned to a nearly pre-pregnant state
 Physical Adjustments:
 Fatigue
 Hormone changes
 Return to menstruation
 Involution: process by which the uterus returns to its prepregnant size 5–6 weeks after birth
 Weight loss/return to exercise
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The Postpartum Period
 Emotional and Psychological Adjustments:
 Emotional fluctuations are common

“Baby Blues” experienced by 70% of new mothers in the
U.S.
 Typically resolves in 1–2 weeks, without treatment
 Postpartum Depression
 Excessive sadness, anxiety, and despair that lasts for two weeks or longer
 Experienced by 10% of new mothers
 Hormonal changes after birth may play a role
 May affect mother–child interactions
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Postpartum blues: symptoms appear 2 to 3 days after delivery and subside within 1 to 2 weeks
Percentage of U.S. Women Who
Experience Postpartum Blues and Postpartum Depression
70%
20% 10%
No symptoms
Postpartum depression: symptoms linger for weeks or months and interfere with daily functioning
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The Postpartum Period
 A Father’s Adjustment:
 Many fathers feel that the baby gets all of the mother’s attention
 Parents should set aside time to be together

Father’s reaction is improved if he has taken childbirth classes and is an active participant in the baby’s care
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Bonding
 Bonding: the formation of a connection, especially a physical bond, between parents and the newborn in the period shortly after birth
 Isolation of premature babies and use of drugs in birth process may harm bonding process

Bonding may be a critical component in the child’s development
 However, close contact in the first few days may not be necessary
 Most hospitals offer a rooming-in arrangement while mother and child are in the hospital
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