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Human Dev. Chapter 3

Birth

  • Overview of Chapter 3 (from the transcript): 01 Birth, 02 Birth Complications, 03 The Competent Newborn.

  • The Beginning of Labor

    • When will baby be born?

    • Pregnancy is said to last 40\text{ weeks}, but often ranges between 37\text{ and }42\text{ weeks}.

    • Due dates are educated guesses; only around 5\% of women give birth on their due date.

    • What are Braxton-Hicks contractions?

    • Uterine contractions that prepare the uterus for delivery.

    • Known as “practice contractions” or “false labor.”

    • What causes labor to begin?

    • Corticotropin-releasing hormone (CRH) triggers the release of hormones, including oxytocin, which triggers contractions.

  • The Body at Work

    • uterus: hollow organ in a woman’s pelvis where the fetus develops.

    • placenta: organ that provides nourishment and oxygen via the umbilical cord between mother and fetus.

    • umbilical cord: connects fetus to placenta; delivers oxygen and nourishment; also removes waste.

    • amniotic fluid: surrounds the fetus; cushions movements; protects from infection and injury; helps regulate fetal body temperature.

    • cervix: the neck of the uterus that separates it from the vagina.

    • vagina: muscular canal that connects the uterus and cervix to the outside of the body.

  • The Process of Labor

    • Contractions:

    • The uterus opens and closes to push the fetus’ head against the cervix.

    • The cervix dilates (opens) and effaces (softens/shortens).

    • Contractions become strong enough to move the fetus into the birth canal and out.

    • Pattern: begin irregularly—every 8–10 minutes, lasting about 30 seconds; become more intense and regular—every 2 minutes, lasting about 2 minutes.

    • Three Stages of Labor:

    • Stage 1: contractions (early labor, active labor, transition).

    • Stage 2: pushing, birth.

    • Stage 3: delivery of the umbilical cord and placenta.

  • The Three Stages of Labor (detailed)

    • Stage 1:

    • Early Labor: mild to moderate contractions; cervical dilation begins.

    • Active Labor: intensified contractions; continued dilation.

    • Transition: short but intense period; cervix dilates from about 8\text{–}10\text{ cm}.

    • Stage 2:

    • Cervix fully dilates to 10\text{ cm}.

    • Mother pushes; baby is born; episiotomy may be done.

    • Umbilical cord (still attached to neonate) is delivered.

    • Placenta is delivered.

    • Postpartum care begins.

    • Stage 3:

    • Delivery of the placenta and completion of the birth process (postpartum care follows).

    • How long does labor last?

    • Typically, the first birth is the longest; subsequent births are shorter, but there is wide variation among women and births.

  • After Birth: Apgar Scale

    • The Apgar score is used to check a newborn’s overall health shortly after birth.

    • Each indicator is scored from 0–2, contributing to a total score from 0\text{ to }10.

    • The five indicators:

    • Appearance (skin color)

    • Pulse (heart rate) – presence and rate

    • Grimace (reflex irritability)

    • Activity (muscle tone)

    • Respiration (breathing)

    • Interpretation:

    • Scores of 7-10: most babies fall in this range.

    • Scores of 4-7: may require help to begin breathing.

    • Scores below 4: require immediate, lifesaving intervention.

  • APGAR SCORES EXPLAINED (indicator-by-indicator mapping)

    • Appearance (A):

    • 0 Points: Blue/Pale skin color.

    • 1 Point: Pink body; blue extremities.

    • 2 Points: Pink all over.

    • Pulse (P):

    • 0 Points: Absent.

    • 1 Point: Below 100 bpm.

    • 2 Points: Over 100 bpm.

    • Grimace (G) / Reflex irritability:

    • 0 Points: Floppy.

    • 1 Point: Minimal response to stimulation.

    • 2 Points: Prompt response to stimulation.

    • Activity (A) / Muscle tone:

    • 0 Points: Absent.

    • 1 Point: Flexed arms and legs.

    • 2 Points: Active movement.

    • Respiration (R):

    • 0 Points: Absent.

    • 1 Point: Slow and irregular.

    • 2 Points: Vigorous cry.

  • After Birth: Low Apgar Scores

    • Low Apgar scores can indicate problems present before birth or problems that occurred during childbirth.

    • Anoxia: restriction of oxygen to the baby during birth; can lead to cognitive deficits and permanent brain damage.

    • Causes of low Apgar scores include a wrapped or pinched umbilical cord.

  • After Birth: Newborn Medical Screening

    • Apgar scores are immediate; additional screening occurs around 24 hours after birth.

    • All states require certain newborn screening; variations exist by state; consent/refusal rules vary.

    • Blood taken from a heel prick tests for: ext{PKU},\;\text{Hypothyroidism},\;\text{Sickle Cell Disease},\;\text{Cystic Fibrosis}.

    • Additional checks assess oxygen levels in the blood and hearing ability.

    • Neonates are given a vitamin K shot and an antibiotic eye ointment.

  • After Birth: Physical Appearance & Bonding

    • Noteworthy neonatal physical traits:

    • Vernix: white, greasy coating on the baby’s skin.

    • Lanugo: fine fuzz covering the baby’s body.

    • Bonding: close physical and emotional contact between mother and baby was once considered critical in the hours after birth (critical period).

    • Skin-to-skin contact and infant massage are important and beneficial, but there is no evidence for a single critical period.

  • Birthing Decisions—How? Who? Where?

    • How?

    • About 70\% of women choose epidural anesthesia (numbness from the waist down; generally safe).

    • Neonate may be less physiologically responsive and cry more.

    • Other options include Lamaze, the Bradley Method, mindfulness birthing, hypnobirthing, or water birthing.

    • A related resource link: https://www.youtube.com/watch?v=sOT9BGMKZjk

    • Who and Where?

    • Traditionally, obstetricians deliver babies in a hospital setting.

    • Midwives may deliver babies in hospitals, birthing centers, or homes.

    • A doula may provide support for the mother before, during, and after birth.

Birth Complications

  • Preterm/Low-Birthweight Infants

    • Definitions:

    • Preterm (premature): born before 38\text{ weeks}.

    • Birthweight is a key indicator of fetal development.

    • Average birthweight: 7.5\text{ pounds} (≈ 3400\text{ g}).

    • Low birthweight: less than 5.5\text{ pounds} (≈ 2500\text{ g}).

    • Low birthweight does not always indicate preterm birth; some neonates are small-for-gestational-age (SGA).

    • SGA: weighs \leq 0.90\times the weight of infants at the same gestational age.

    • Causes and considerations:

    • May be caused by inadequate nutrition and/or oxygen during pregnancy.

  • Preterm/Low-Birthweight: Risks and Care

    • Risks correlate with degree of prematurity and birthweight:

    • Increased risk of infection.

    • Respiratory Distress Syndrome (RDS) due to underdeveloped lungs; often treated in an incubator.

    • Sensitivity to environmental stimuli that can disrupt breathing or heart rate.

    • Care includes:

    • Longer hospital stay to foster weight gain and development.

    • Kangaroo care (skin-to-skin contact).

    • Infant massage.

  • Very-Low-Birthweight Infants

    • Very low birthweight: < 3\text{ lb }4\text{ oz} (≈ 1500\text{ g}) or birth before 30\text{ weeks}.

    • These infants look very different from typical newborns.

    • Survival rates have improved significantly since the mid-1980s.

    • Age of viability has decreased to 22\text{ weeks}, with about a 50\% survival chance at that threshold.

    • Problems associated with very low birthweight are more pronounced.

    • Notable references from public media/resources include examples of premature infants and NICU programs (e.g., NICU Small Baby Program).

  • Preterm/Low-Birthweight Deliveries: Causes

    • About half of preterm deliveries are unexplained.

    • Other half related to:

    • Prior pregnancy with preterm delivery.

    • Pregnancy with multiples (twins, triplets, etc.).

    • Maternal age (younger than 15\text{ or older than }40).

    • Short interval between pregnancies (conceiving again within 6 months).

    • Paternal age (older fathers).

    • Maternal lifestyle and general health.

    • Certain medical conditions, e.g., diabetes, preeclampsia (high blood pressure during pregnancy).

  • Postmature Infants

    • Postmature: born at or after 42\text{ weeks}.

    • Risks:

    • Placenta may not provide adequate blood supply.

    • Low amniotic fluid (oligohydramnios).

    • Labor becomes riskier.

    • Management: doctor may schedule induction or cesarean delivery.

  • Cesarean Delivery

    • Definition: baby is surgically removed from the uterus.

    • Reasons for cesarean delivery:

    • Fetal distress.

    • Breech (feet first) or transverse presentations.

    • Large head or other complications.

    • Trends: cesareans more prevalent in mothers older than 40.

    • Contributors to rising cesarean rates:

    • Fetal monitors have contributed to increases in cesarean deliveries (some may be unnecessary).

    • Risks:

    • To mother: longer recovery, higher infection risk, potential dissatisfaction with birth experience.

    • To baby: stress-related hormones may not be released due to lack of labor experience.

  • Stillbirth, Maternal, and Infant Mortality

    • Stillbirth: baby is not alive at delivery (can occur during childbirth; may be detected beforehand).

    • Infant Mortality Rate in the US:

    • 2022: 5.6\text{ deaths per }1000\text{ live births} (decreasing since the 1960s).

    • Most common causes: birth defects, preterm birth, SIDS.

    • Maternal Mortality Rate in the US:

    • 2023: 18.6\text{ deaths per }100{,}000\text{ live births} (down from 32.9\text{ in }2021).

    • Note: US infant and maternal mortality rates are higher than in most developed nations; disproportionately high for Black women and children.

  • Postpartum Depression

    • Postpartum Depression: deep depression following childbirth.

    • Affects around 10\% of new mothers.

    • Symptoms include:

    • Deep and enduring sadness; withdrawal from family and friends; overwhelming fatigue; irritability or anger.

    • Can last several months or years; some may experience a break from reality.

    • Linked to hormonal changes after birth, but higher likelihood if there is a personal or family history of depression.

    • Postpartum anxiety may be even more prevalent.

The Competent Infant

  • Physical Competence

    • Neonates interact with the world through reflexes (automatic responses to stimuli):

    • Sucking, Swallowing, Rooting, Coughing, Sneezing, Blinking.

  • Sensory Capabilities

    • Sight:

    • Vision is present but acuity is not fully developed.

    • Neonates pay attention to high-contrast objects; can discriminate brightness; have some size constancy and rudimentary color perception.

    • Hearing:

    • Hearing is present and improves with age.

    • Reacts to sound (startle) and recognizes familiar sounds.

    • Touch, taste, and smell: well developed at birth.

  • Learning Capabilities

    • Classical Conditioning

    • Newborns can learn through classical conditioning.

    • Classic example: Little Albert experiment (John B. Watson) demonstrated conditioned fear responses in infants (historical context and ethical concerns).

    • Real-world demonstrations in newborns include:

      • Turning head when the head is stroked while a small amount of sweet liquid is given (conditioning of a response).

      • Increased activity level when a certain odor is presented via infant massage.

    • Operant Conditioning

    • Reinforcement and punishment shape voluntary responses.

    • Example: a newborn learns that crying leads to immediate attention from a parent.

  • Habituation

    • Habituation: a primitive form of learning where a response to a repeated stimulus decreases over time.

    • Starts with an orienting response (the initial reaction to a new stimulus).

    • Example:

    • A baby is feeding in a quiet room; a sibling enters and talks; the baby stops feeding (orienting response).

    • If the sibling continues to talk each feeding, the infant may habituate and stop reacting (habituation).

  • Social Competence

    • Newborns have the ability to imitate others’ behavior; there is ongoing debate about what constitutes true imitation vs. exploratory behavior.

    • Imitation is thought to provide an important foundation for social interaction later in life.