The Developing Person Through the Life Span 8e by Kathleen Stassen Berger Chapter 4 – Prenatal Development and Birth PowerPoint Slides developed by Martin Wolfger and Michael James Ivy Tech Community College-Bloomington Reviewed by Raquel Henry Lone Star College, Kingwood Prenatal Growth Three main periods of prenatal development 1. Germinal Period (1st two weeks after conception): rapid cell division and beginning of cell differentiation 2. Embryonic Period (3rd through 8th week): basic forms of all body structures develop 3. Fetal Period (9th week until birth): fetus grows in size and matures in functioning The Germinal Period • Zygote begins duplication and division within hours of conception • Development of the placenta – Organ that surrounds the developing embryo – Sustains life via the umbilical chord • Implantation (about 10 days after conception) – Developing organism burrows into the placenta that lines the uterus The Germinal Period The Embryonic Period Embryo • 3rd through the 8th week after conception • Begins when the primitive streak appears down the middle of the cell mass • Primitive streak becomes the neural tube and later the brain and spinal column • Eyes, ears, nose, and mouth form • Heart begins to pulsate • Extremities develop and webbed fingers and toes separate The Embryonic Period The Fetal Period Fetus • 9th week after conception until birth • Genitals form and sex hormones cause differences brain organization • Cephalocaudal and proximodistal growth • Heartbeat detectable via stethoscope • Cortex is not fully mature at birth • Brain at birth is biggest part of baby The Fetal Period Age of viability • Age at which a preterm newborn may survive outside the womb with medical care • About 22 weeks after conception • Brain is able to regulate basic body functions • Chances of survival increase with each day after the 22week mark The Fetal Period Birth • Fetal brain signals the release of hormones to trigger the mother’s uterine muscles • Labor begins – Average duration for first babies: 12 hours – Quicker labor for later babies • Apgar scale – Quick assessment of newborn’s heart rate, breathing, muscle tone, color, and reflexes – Completed twice (1 minute and 5 minutes after birth) – Score of 0, 1, or 2 in each category – Desired score: 7 (total) or above A Normal, Uncomplicated Birth Birth Medical Assistance Cesarean Section (c-section) • Surgical birth • Fetus can be removed quickly • Rates and reasons for c-sections vary – Lower rates in poorer countries – Higher rates in richer countries – 1/3 of births in the United States • Less trauma for the newborn but slower recovery for the mother • Subsequent cesarean deliveries may be necessary Newborn Survival • Infant mortality has decreased due to better medical care – 1900: 5% – Today: <1 in 200 • Childbirth has become safer for mothers – Death rate in poorest nations: 1 in 20 women • Excessive medical care also has disadvantages – Increase in unnecessary c-sections is associated with higher rate of low-birth weight babies Traditional and Modern Birthing Practices • Home births • Hospital births • Doula – Woman who helps with labor, delivery, breastfeeding, and newborn care – May be related to lower rate of cesarean sections Harmful Substances • Teratogens – Substances and conditions that can impair prenatal development and result in birth defects or even death – Not all teratogens can be avoided – Structural abnormalities are obvious at birth • Behavioral teratogens – Affect the child’s developing brain • Developmental retardation, hyperactivity, and learning disabilities – Effects do not become evident for months or years Risk Analysis • • • • Knowing which risks are worth taking How to minimize chance of harm Teratology: science of risk analysis Threshold effect: when a teratogen is harmless in small doses but becomes harmful at a certain level (threshold) Applying the Research • Fetal alcohol syndrome (FAS) – A cluster of birth defects including abnormal facial characteristics, slow physical growth, and retarded mental development – May occur in the child of a woman who drinks alcohol while pregnant Low Birthweight • Low birthweight (LBW) – Less than 2,500 grams (5½ pounds) at birth – United States • Steady increase in LBW over the past 25 years • 8% of newborns are seriously underweight • More susceptible to teratogens, higher birth risks, lower survival rate • Very low birthweight (VLBW) – Under 1,500 grams (3 pounds, 5 ounces) at birth • Extremely low birthweight (ELBW) – Under 1,000 grams (2 pounds, 3 ounces) at birth Preterm or Slow Growing? • Preterm – Birth that occurs at 35 or fewer weeks after conception – Usually associated with low birthweight • Small for gestational age (SGA) – Birthweight is significantly lower than expected, given the time since conception – Suggests impairment throughout prenatal development and serious problems Complications During Birth • Cerebral palsy: -damage to the brain’s motor centers -speech and/or muscles are impaired • Anoxia: -lack of oxygen -over time can cause brain damage or death The Newborn • Brazelton Neonatal Behavioral Assessment Scale (NBAS) – A test that measures responsiveness – records 46 behaviors, including 20 reflexes Moving and Perceiving The Newborn • The first movements are not skills but reflexes, involuntary responses to a particular stimulus. The Newborn Some reflexes aid survival • • • • • • • breathing thrashing shivering sucking rooting swallowing spitting up The Newborn Other reflexes signify normal functioning: • Babinski reflex. When feet are stroked, their toes fan upward. • Stepping reflex. When held upright with feet touching a flat surface, infants move their legs as if to walk. • Swimming reflex. When laid horizontally on their stomachs, infants stretch out their arms and legs. • Palmar grasping reflex. When something touches infants’ palms, they grip it tightly. • Moro reflex. When someone startles them, infants fling their arms outward and then bring them together on their chests, as if to hold on to something, while crying with wide-open eyes. The Father’s Role • Supportive father helps mother stay healthy • Father can decrease or increase mother’s stress (affects fetus) • Most fathers are helpful to their pregnant wives • Two way street: Pregnant mothers should support, involve, and encourage fathers The Father’s Role • Couvade: symptoms of pregnancy and birth experienced by fathers • Parental alliance: – cooperation between a mother and a father based on their mutual commitment to their children – the parents support each other in their shared parental roles. Postpartum Depression • Sadness and inadequacy felt by 8-15% of new mothers in the days and weeks after giving birth • Symptoms range from baby blues to postpartum psychosis • baby care feels burdensome and thoughts of mistreating the infant may exist • Paternal involvement can have beneficial effect – Some fathers are depressed themselves • Causes for Postpartum Depression vary Bonding Parent-Infant Bond • The strong, loving connection that forms as parents hold, examine, and feed the newborn • Early skin-to-skin contact is not essential • Cross-fostering in monkeys – Newborns are removed from their mothers and raised by another female or male – Strong and beneficial relationship sometimes develops Bonding • Birth complications can have lingering impact on later life • Mothers and fathers should help with early caregiving if newborn must stay in the hospital • Kangaroo care – Child-care technique in which the mother of a LBW infant holds the baby between her breasts – Allows baby to hear mother’s heartbeat and feel her body heat – Research confirms beneficial effects