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Chapter 4:

Prenatal Development and Birth

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PrenatalDevelopment

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

– Germinal period.

– Embryonic period

– Fetal period

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Significant Development in the Germinal Period

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Teratogens• Any agent that can cause birth defects.

Not just illegal drugs and alcohol !

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Most Most serious serious damage damage from from

teratogens teratogens in first in first 2-8 wks2-8 wks

Zygote Embryonic period (wks) Fetal Period (wks)

Period of susceptibility to functional defects

Period of susceptibility to structural defects

Fig. 4.4

1 2 3 4 5 6 7 8 9 16 32 38

Teratogens and Timing of Their Effects on Prenatal Development

Central nervous system Heart

ArmsEyes

Legs Ears

TeethPalate

External genitalia

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Types of TeratogensA. Drugs

1. Prescription Drugs

2. Nonprescription:

--Aspirin

--Caffeine

--Nicotine

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

ALCOHOL(also Non-prescription drug

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

• B. Illegal Drugs– ALL illegal drugs are potential

teratogens(ex. Cocaine, crack, marijuana, heroin, etc) and should be avoided during pregnancy

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• C. Environmental hazards: exposure to radiation or chemicals.

X-raysLeadMethylmercury: Tuna(light canned versus albacore)

Fish to avoid during pregnancy:

shark, swordfish, king mackerel and tilefish

.

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D. Maternal Illness• Toxoplasmosis

• Foodborne Illneses: Listeria,

• Chicken Pox

• HIV/AIDS

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Other Parental Factors

• Maternal factors:

• Maternal diet and nutrition.

• Emotional states and stress.

• Maternal age.

• Paternal factors:

• Paternal exposure to teratogens including smoking.

• Paternal age.

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Care for preterm infants:

– Kangaroo care—holding preterm infant so there is always skin-to-skin contact.

– Massage therapy—Tiffany Field’s research.

©2008 The McGraw-Hill Companies, Inc. All rights reserved.Fig. 4.8

3 lb. 1 oz

3 lb. 7 oz

2 lb. 15 oz

3 lb. 3 oz

3 lb. 5 oz

Infant weight

40 6 8 122 1410

Age (days)

Premature infants who were massaged

Premature infants who were not massaged

Weight Gain Comparison of Premature Infants Who Were Massaged with Those Not Massaged

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The

Postpartum

Period

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• 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.

©2008 The McGraw-Hill Companies, Inc. All rights reserved.Fig. 4.9

Postpartum blues: symptoms appear 2 to 3 days after delivery and subside within 1 to 2 weeks

No symptoms

10%

70%

20%

Postpartum depression: symptoms linger for weeks or months and interfere with daily functioning

Percentage of U.S. Women Who Experience Postpartum Blues and Postpartum Depression

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A Father’s Adjustment:

– Generally ignored, but fathers go through considerable adjustment.

– Some feel baby has replaced them in terms of mother’s affection.

– Fathers should actively care for the baby.

– Parents should set aside time to be together.

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

– Usually occurs in period shortly after birth.

– 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.