PRENATAL DEVELOPMENT AND BIRTH

Prenatal DevelopmentTime of fastest development in life

span Environment extremely importantConception

Ova travels from ovary to uterusPenetration by 1 of 300-500 spermOutcome: single-celled ZYGOTE

Prenatal Stages

Germinal period: days 1-14 Implantation: 1/2 are successful Miscarriage: 15% (recognized) to 50%

Embryonic period: 3rd to 8th week Organogenesis, Sexual differentiation

Fetal period: 9th week – birth Proliferation, migration Differentiation of stem cells Ends in tremendous brain development

Prenatal EnvironmentReciprocal influence

Person and environment Good and bad influences important

Teratogen: Environmental agent Harms the developing fetus Critical Period: Organogenesis Dosage and duration Genetic make-up: Susceptibility

• The critical periods of prenatal development. Teratogens are more likely to produce major structural abnormalities during the third through the eighth prenatal week. Note, however, that many organs and body parts remain sensitive to teratogenic agents throughout the nine-month prenatal period

Teratogens: Drugs Thalidomide (for morning sickness)

All or parts of limbs missingTobacco: Miscarriage, low birth weight,

SIDS, slows fetal growthAlcohol: FAS

Small, facial deformities, retardationCocaine: Processing difficulties

• (A) Characteristic features of a child with fetal alcohol syndrome (FAS).

(B) Child with FAS, illustrating many features in the drawing. Such children may also have cardiovascular and limb defects.

Teratogens - DiseasesRubella (German Measles)

Blind, deaf, heart, brain

Syphilis: Miscarriage, blind, deaf, heart, brainAfter 18th week

AIDS: Mothers transmit to babies (15%-35%)Prenatally, perinatally, postnatally

Teratogens: Environmental Hazards

Radiation: MR, leukemia, cancer, mutations, spontaneous abortions, etc.Avoid X-rays when pregnant

Pollutants In air and waterLead: MR (also postnatally)

The Mother’s State

Age: Typically age 16-35 15 or younger don’t seek prenatal care

Birth complications, low birth weightOver 35:Miscarriage, Down Syndrome

(father’s age also) Emotion: Stress can stunt fetal growth

Positive outlook most helpful Nutrition: 25-35 lb weight gain

Malnutrition: Smaller neurons, brain, child

The Father’s State Research limited except for genetic contribution Father’s age can also be influential

Over 35: Increased number miscarriages, heart defects, Down Syndrome

Over 50: Higher risk for schizophrenia Exposure to environmental toxins

Radiation, anesthetic gases, pesticidesDamage to genetic material in sperm

Postnatal Depression

Baby Blues: mild, commonClinical depression: 1/10

Previous depression commonChildren of Depressed Mothers

Insecurely attached, less responsive

Negative to other children

The Father’s Experience Accepted, expected in delivery rooms Attend prenatal classes with wife Experience described as a significant

event Anxiety, stress common during delivery Relief, pride, joy when baby is born Sometimes depression following birth Disappointed if sex does not resume soon

The Neonatal Environment Culture, early socialization, health status

E.g., low birth-weight babies (8% in US) Less than 5½ lbs Strongly linked to low SES Environment: Neonatal intensive care Risk: Blindness, deafness, CP, autism,

cognitive, and later academic problems Parenting must be attentive, responsive

• Modern technology permits survival of younger and smaller babies, but many experts believe we have reached the lowest limits of viability at 23-24 weeks gestation.

Learning Objectives What are the advantages of breast feeding? Are there disadvantages of breast feeding? How can at-risk newborns be identified? What treatments are available to optimize

development of at-risk babies? To what extent are the effects of the prenatal and

perinatal environments long lasting? What factors influence whether effects are lasting?

Breast or Bottle? Breast feeding most natural nutrition Practices vary across cultures Health benefits great for breast-fed infants

At least first 6 months recommended More likely to bottle feed: Factors

Younger, low SES, less education, employed, African American

US values toward breast feeding ambivalent

Low Birth-Weight Babies < 5½ pounds: “Small for date” or “preterm”

Leading cause of infant mortality 8% of all births, 65% of all infant deaths

Factors: Low SES, smoking, stress, multiples Worse for minority, poverty, single-parent children For most, significant catch-up growth

Low Birth-Weight Infants Greater risk for blindness, deafness, CP, autism,

health problems - especially respiratory problems

Factors Helpful for LBW Infants

Breastfeeding, skin-to-skin contact, massage Responsive parenting, intellectual stimulation Early intervention programs work with

parentsChildcare education and supportGrowth-enhancing home environment

Consistently attentive, responsive parenting

Risk and Resilience Not all high-risk infants have problems Werner: Kauai Longitudinal study (40 yrs) Findings:

Effects decrease over time Outcomes depend on postnatal environment Protective factors

Personal resources Supportive postnatal environment