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Chapter 4:

Prenatal Development  and Birth 

Prenatal Development 

•         Prenatal development is divided into 3 periods and lasts approximately 266 days 

–        Germinal period: first 2 weeks after conception, zygote created (see Fig. 4.1) 

–        Embryonic period: occurs from 2 to 8 weeks after conception (see Fig. 4.2) 

–        Fetal period: begins 2 months after conception and lasts until birth 

•         Teratogen: any agent that causes birth defects

–        Drugs (prescription, nonprescription)

–        Alcohol, tobacco

–        Environmental pollutants

–        Infectious diseases

–        Nutritional deficiencies

–        Maternal stress

–        Advanced age of a parent 

•         Severity of damage to the unborn depends on

–        Dose

–        Time of exposure

–        Genetic susceptibility 

•         Fetal alcohol syndrome: abnormalities in newborn due to mother’s heavy use of alcohol in pregnancy 

•         Abnormalities include:

–        Facial deformities

–        Defective limbs, face, heart

–        Most are below-average intelligence

–        Some are mentally retarded 

•         Moderate drinkers during pregnancy had babies who were less attentive and alert even at 4 years of age 

•         Maternal smoking can cause

–        respiratory problems

–        SIDS

–        ADHD

–        low birth weight 

•         Illegal drugs that harm during pregnancy:

–        Cocaine

–        Marijuana

–        Heroin 

•         Incompatible blood types (Rh factor) 

•         Environmental hazards: exposure to radiation or chemicals  

•         STDs, HIV infection, AIDS 

•         Other maternal and paternal factors  

Birth 

•         Three stages of birth: 

–        Uterine contractions begin at 15 to 20 minutes apart and last 1 minute; this stage lasts an average of 12 to 24 hours 

–        Baby’s head begins to move through dilated cervix opening; this stage lasts 1.5 hour on average 

–        Afterbirth: umbilical cord, placenta, and other membranes are detached and expelled 

•         Birth complications include anoxia:

insufficient oxygen to brain when delivery lasts too long 

•         Birth and delivery methods:

–        Hospital delivery room

–        Home delivery with midwife

–        Lamaze method 

•         Comparing birth weights in the United States and other countries 

•         Causes of low birthweight:

–        Preterm babies

–        Small-for-date babies

–        Problems in developing countries 

•         Possible consequences of low birthweight:

–        Brain injuries

–        Lung and liver diseases

–        Learning disabilities

–        ADHD

–        Lower levels in reading and math achievement

–        Deficits are evident in adulthood 

•         About 50% of low-birthweight children are enrolled in special education programs 

•         Low birthweight is linked to asthma 

•         Some defects can be improved with

–        Early speech therapy

–        Intensive enrichment programs

–        Kangaroo care and massage therapy 

Measuring neonatal health and responsiveness: 

•         Apgar Scale, used 1–5 minutes after birth:

–        evaluate heart rate, body color, muscle tone, respiratory effort, and reflex irritability  

•         Brazelton Neonatal Behavioral Assessment Scale performed within 24–36 hours after birth 

–         27 items are organized into 4 categories – physiological, motoric, state, and interaction 

–        Assesses newborn’s neurological development, reflexes, and reactions to people 

The  Postpartum  Period 

•         Postpartum period lasts about 6 weeks after childbirth when woman adjusts physically and psychologically back to the prepregnant state 

–        Influenced by preceding conditions and experiences  

–        Mother learns to care for the baby, feel good about herself and those close to her 

–        Physical: hormone changes, weight loss, return to menstruation, loss of energy or fatigue 

–        Psychological: feelings of depression, anxiety, coping in new role, excessive worrying

–        Bonding (formation of emotional attachment) between infant and mother:

–        Usually occurs in period shortly after birth

–        Is this a critical component in child’s development?

–        Isolation of premature baby and use of drugs in birth process may harm bonding process

–        Some experts advocate a rooming-in arrangement while mother and child are in the hospital