Ch 3 Prenatal Development and Birth

what does prenatal development begin and end with

begins at conception (process of fertilization of egg by a sperm and ends with birth

how long does development take

38 to 40 weeks (~9 months)

three periods

• germinal (0-2 weeks)

• embryonic (2-8 weeks)

• fetal (8 weeks - birth)

germinal period(0-2 weeks)

• creation of fertilized egg = zygote

• beginning of cell division and differentiation starts to take place

• as cell division continues, the mass of cells that will eventually develop into the embryo (called the blastocyst)

• blastocyst is surrounded by the trophoblast, outer layer of cells that will later provide nutrition and support for the embryo

• attachment of zygote to the uterine wall

embryonic period (2-8 weeks)

• begins once blastocyst attaches to uterine wall (called embryo)

• cell differentiation further into bodily systems

• life support system for cells start of form (ex. placenta, umbilical cord)

• organs first start to form (organogenesis)

organs appearing in the embryonic period

• day 21: eyes begin to appear

• day 24: heart starts to form clearly

• week 4: arm and leg buds emerge, blood vessels appear

• weeks 5 to 8: arm and legs further develop, face starts to form

just over an inch long by the end of the embryonic period

fetal period (8 weeks - birth)

• referred to as a fetus

• facial features and limbs become more easily distinguished

• arms, legs, head move spontaneously

• sex can be identified in most cases (~3 months)

• mother can start to feel movement (~5 months)

• around 6 months, fetus has some chance of survival outside of the womb (considered viable)

• lungs not fully mature

• continues growing through 9 months)

• born at average 8lbs and 20 inches long (in the US)

the three trimesters

• prenatal development period is divided into 3 equal-length parts

• not the same as prenatal periods

• fetal period begins towards the end of the first trimester

• viability begins at the end of the second trimester

teratogen

any agent w/ potential to negatively affect development during prenatal period

• physical birth defects

• altered brain formation

• influence cognitive or behavioral functioning

• may not immediately apparent at birth

influence of teratogens vary by:

• dose: greater the dog (such as the drug), greater the effect

• genetic susceptibility: some people may be more vulnerable to particular teratogen based on their genetics

• timing of exposure

timing of teratogen exposure continued

• can be more vulnerable at different points of development

• germinal period > may prevent implantation into uterine wall

• embryonic period > structural defects in various organs

• fetal period > how well organs function, stunted growth

embryonic period generally most vulnerable period

• organogenesis/ risk of structural defects of organs at its greatest

examples of teratogens: prescriptions/ nonprescription drugs

• antibiotics

• certain antidepressants

• certain hormones supplements

• diet pills

• high doses of aspirin

psychoactive drugs

drugs which act on the nervous system to alter states of consciousness, modify perception, or change mood)

• caffeine

• alcohol

• nicotine

• cocaine

• marijuana

• heroin

caffeine

• common in many people’s diet

• mixed results on extent of effects

• some data to suggest related to lower birth among babies

• US FDA recommends pregnant women avoid or consume sparingly

nicotine

• smoking effects prenatal development, birth complications, and postnatal development

• lower birth (implicated in as many as 25% of infants born with low birth weight

• fetal death, respiratory problems in baby (and later as adolescent)

• risk factor for development of ADHD

• not limited to just tobacco cigarettes (e-cigarettes also contain nicotine)

• 23% of adolescent and 15% of adult pregnant women report having smoked in past month

cocaine

• quickly crosses placenta to reach fetus to harm development

• low birthweight, neurological/cognitive impairments

• impaired motor development, slowed rate of growth, learning disabilities, externalizing behavior problems

marijuana

• low birth weight

• alter brain development (lower intelligence in children)

heroin

• child themselves exhibit withdrawal symptoms (ex. tremors, irritability, abnormal crying, disturbed sleep, impaired motor control)

• continued behavior problems during childhood

• attention deficits

alcohol

• fetal alcohol syndrome (FAS) brought on my alcohol use during pregnancy resulting in facial abnormalities, deformities, heart defects, intellectual disabilities, and learning problems

• general recommendation: no amount of alcohol is safe

maternal diseases and infections can also cause damage during birth

• genital herpes (if passed through birth canal)

• HIV/AIDS (although may be born not infected at all)

• variety of other infectious disease

maternal diet and nutrition

• embryo or fetus depends completely on mother for nutrition

• malnutrition in mother:

  • developing embyro/fetus needs those nutrients to develop properly

  • children born to malnourished mothers more likely to be born malformed

• obesity in mother:

  • increased risk of hypertension (high blood pressure), diabetes, respiratory problems, complications during pregnancy or birth

adolescent mothers

• mortality rate for children double that of mothers in their 20s

• may be tied to SES or decision making?

• least likely age group to obtain proper prenatal care from clinics

women 35 years and older

• increased risk of some disorder (ex. down syndrome)

• tied to increased risk of mother’s eggs possessing genetic anomaly that disrupts typical prenatal development

• risk increases for low birth weight preterm delivery, fetal death

• risk rises over time

emotional states and stress

mother’s emotional states may influence fetus as well

• altering mother’s physiology

• influencing mother’s behavior

chronic anxiety/stress

• increased blood pressure, stress hormones

• cognitive problems, emotional problems, ADHD, language delays

harmful coping methods

• mother may be more llkely to engage in harmful behaviors to cope

• ex. substance use/teratogens

paternal factors

exposure to lead, radiation, certain pesticides

• may cause abnormalities in sperm

• may lead to miscarriage or certain diseases in child

smoking in fathers

• exposure to chemical that may lead to abnormalities in sperm

• second-hand exposure for mother/fetus

age of father:

• risk of fetus seem to increase as fathers’ age reaches 40+

• rates of autism, schizophrenic disorders

relationship with mother

• supportive or conflictual?

prenatal care

• scheduling several visits for regular medical checkup

• screen for manageable conditions/treatable diseases

• educational services for parents-to-be:

  • nutrition information

  • benefits of low-level exercise

  • provide information about pregnancy/process of childbirth

childbirth

• in the us, 98% of childbirths take place in hospital

• range of options for method of delivery, most of which are hotly debated

medication to reduce pain in childbirth

• birthing process often involves great pain to mother

• concern about higher dosages and possible negative effect on the fetus

• may reduce mother’s ability to push fetus out (ex. sedation, numbness)

• individual differences in sensitivity to certain meds (mother and child)

• tricky to make decisions (as both the parents and medical care provider)

natural childbirth and pain reduction

• push for non-medication based ways to reduce pain during birth

• breathing techniques, relaxation techniques, husband or other trusted individual as coach during birth to help promote relaxation

Cesarean delivery

• medical procedure where baby is surgically removed from mother’s uterus by incision in her abdomen

• generally not recommended as the default (~32% of births in US)

• performed when complications arise during birthing process

• ex. mother unable to push, baby’s head too large, baby in breech position

assessing newborn

• apgar scale: widely used tool used to assess health of newborn babies at one and five minutes after birth

• assessment of: heart rate, respiration, muscle, body color, reflex irritability

• depending on infant’s score, condition classified as either good, signs of developmental difficulties, or emergency situation

Apgar scale

• 5 categories

• higher the score, the better

• the total score is then summed up across all 5 categories to assess overall status of the newborn

infant size and health

• low birht weight (,5 pounds, 8 oz)

• very low birth weight infants (<3 pounds, 4 oz)

• extremely low birth weight infants (<2 pounds)

• preterm infants: born three weeks or more before expected full-term pregnancy ( prior to 37 weeks gestation)

• small for date infants have birth weight below normal, considering how far along pregnancy is compared to other babies at same gestational age

  • ex. baby weighs less than 90% of all other babies at same gestational age

• risk factors: nutrition, substance use, stress, maternal age, low access to prenatal care, low SES/ poverty

• lower birth weight/earlier the preterm delivery > higher risks

  • viability

  • developmental disorders

important statistics

• human have been giving birth a long time

• risks to pregnancy are generally very low for healthy adults

• majority babies are born at full-term, healthy, and happy

• 97% of babies are born in the US without any kind of major defect

• many defects (webbed toes, some heart defects) are treatable

postpartum period

the period after childbirth/delivery that lasts for about six weeks (or until mother’s body has returned to nearly pre-pregnant state)

• requires some physical, emotional, and psychological adjustments for parents

• focus has generally been on mother, but more research and acknowledgement being given to experience of father in recent times

postpartum period: physical adjustments

• lack of energy/exhuastion/fatigue

• loss of sleep

• can lead to increased stress, conflict with partner

• undermine confidence in own ability to adjust to life with baby

postpartum period: emotional/psychological adjustments

• “postpartum blues” (“baby blues”) are common feelings of sadness parents may feel two to three days following birth of their child

• reported by ~70% of new mothers

• may come and go

• generally resolves on its own w/o intervention in one or two weeks

postpartum depression

involves a major depressive episode following birth/delivery of a child

• feelings of sadness, anxiety, or despair lasting a period of at least two weeks that are severe enough to impair daily functioning

• experienced by ~10-14% of new mothers

• typically occurs about four weeks after birth/delivery

• can last for several months without treatment

risk factors for postpartum depression

• History of clinical depression

• Depression or anxiety during pregnancy

• Neuroticism (trait disposition to experience negative affects)

• Low self-esteem

• Postpartum blues

• Having a poor marital relationship

• Low levels of social support

exercise and treatments may aid

postpartum period with faterh

• fathers also undergo adjustment during the postpartum period

• may also experience depression

  • ~5% report symptoms of depression in first two weeks following delivery

  • increased odds if mother also develops postpartum depression

• feelings of neglect in the relationship/ mother always prioritizes baby over father

• depression in both parents can impair the bonding process with their child during postpartum period

early bonding

• time period shortly following birth can be a special time of bonding between parents and newborn (emotional and physical)

• concern among that there is a critical period for bonding in first few days following birth of baby, where newborn must have close contact with mother to develop optimally

• research suggests skin contact with parent during first days of life is not critical, however, hospitals should strive to allow parents to interact with their newborns as much as possible

• kangaroo care

kangaroo care

skin-to-skin contact between baby and parent, where baby is held upright against the parent’s bare chest

• takes 2-3 hours per day

• becomes more commonplace in the US hospital system

benefits:

• helps stabilize infants heartbeat, temperature, breathing

• healthy weight gain in preterm infants

• decreased risk of mortality in low-birth-weight infants