Chapter 4 Prenatal Development and Birth

Chapter 4- Prenatal Development Time of fastest development in life span Environment extremely important Conception Ova travels from ovary to uterus Penetration by 1 of 300-500 sperm Outcome: 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 Environment Reciprocal influence Person and environment Good and bad influences important Teratogen: environmental agent Harms the developing fetus Critical Period: Organogenesis Dosage & duration Genetic make-up: susceptibility

Figure 4. 3 The critical periods of prenatal development Figure 4.3 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 Figure 4.3

Teratogens-Drugs Thalidomide (for morning sickness) All or parts of limbs missing Tobacco: miscarriage, low birth weight, SIDS, slows fetal growth Alcohol: FAS Small, facial deformities, retardation Cocaine: Processing difficulties

Figure 4.6 A. Characteristic features of a child with fetal alcohol syndrome. B. Child with fetal alcohol syndrome illustrating many of the features in the drawing. These children may also have cardiovascular and limb defects. Figure 4.6

Teratogens - Diseases Rubella (German Measles) Blind, deaf, heart, brain Syphilis:miscarriage, blind, deaf, heart, brain After 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 water Lead - MR (also postnatally)

The Mother’s State Age: typically age16 – 35 15 or younger don’t seek prenatal care Birth complications, low birth weight Over 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

Figure 4.8 The three stages of labor: Stage 1: (a) Contractions of the uterus cause dilation and effacement of the cervix. (b) Transition is reached when the frequency and strength of the contractions are at their peak and the cervix opens completely. Stage 2: ( c) The mother pushes with each contraction, forcing the baby down the birth canal, and the head appears. (d) Near the end of Stage 2, the shoulders emerge and are followed quickly by the rest of the baby’s body. Stage 3: (e) With a few final pushes, the placenta is delivered. Figure 4.8

The Perinatal Environment Birth Process: 3 step process Possible Hazards Anoxia – Oxygen shortage: can be severe Complicated delivery Cesarean (“C”) section Medications: can reach baby

The Mother’s Experience Severe pain, anxiety 77% rate it as positive experience Psychological factors Attitude, knowledge, support Cultural factors

Postnatal Depression Baby Blues, mild, common Clinical depression: 1/10 Previous depression common Children of depressed mothers Insecurely attached, less responsive Negative to other children

The Neonatal Environment Culture, early socialization, health status E.g., low birth-weight babies (8% in US) Less than 5 1/2 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

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 factors Supportive postnatal environment