Chapter 2 Flashcards

Question

The germinal stage

Answer 1

Begins at conception and lasts 1–2 weeks. * Involves the growth of the zygote and the start of a connection with the mother’s body. * Mitosis (cell division) starts 24–36 hours after conception. * The zygote divides rapidly: 1 → 2 → 4 → 8 → 16 → 32 cells, etc. * By 2–3 days, a few dozen cells exist; by 4 days, 60–70 cells. * The zygote travels through the fallopian tube to the uterus. * Around day 6, it begins implantation in the uterine wall. * Implantation is complete by day 9 and marks the end of the germinal stage and the start of the embryonic stage.

Answer 2

Week 1–2 (Post-Implantation)  The developing organism is called an embryo.  Rapid growth and organ development begins.  The embryo forms three layers: o Ectoderm: skin, hair, nails, sensory organs, nervous system. o Mesoderm: muscles, skeleton, blood circulation, excretory system. o Endoderm: digestive and respiratory systems, liver, pancreas, glands.  Placenta and umbilical cord begin to form — providing nutrients and oxygen. Week 3  Blood vessels and stomach begin developing.  A heart tube begins to form. Week 4  The heart starts to beat near the end of this week.  Brain and heart areas become more defined.  Embryo is about 0.5 cm long.  No limbs yet; basic body systems begin forming.  Embryo still resembles other animals at this stage. Week 4–6  Woman becomes aware of pregnancy (missed period, positive test).  70% experience nausea, often in the morning.  Frequent urination begins. Week 5  Brain develops rapidly, making 250,000 neurons per minute.  Chest and abdomen form.  Eyes become visible (still closed).  Lung buds, hand and foot plates, and olfactory lobe (smell) begin forming.  Heart changes shape, forming four chambers.  Embryo is about 11–14 mm long.  Arm and leg buds appear. Week 6  Continued development of heart and limbs.  Features like eyes, mouth, ears, and face begin forming. Week 8  Embryo is about 30 mm long.  Arms, legs, hands, feet, and stumpy fingers/toes are visible.  Sexual organs start to develop (sex not yet visible).  Muscles and cartilage begin forming.  Organs like the liver, pancreas, lungs, and kidneys begin functioning slightly. o Liver produces red blood cells. o Stomach starts making digestive juices.

Answer 3

Month 3 (Week 9–12)  The developing organism is now called a foetus.  Sex organs (penis, scrotum, labia) become visible.  Nervous system connects to muscles, enabling movement (not yet felt by the mother).  Foetus is about 7.5 cm long and weighs 28 grams. Month 4 (Week 13–16)  Face becomes more human, body lengthens.  Mother feels movement for the first time.  Heart beats 120–160 bpm.  Reflexes like thumb sucking and hiccups appear.  Foetus is about 25 cm long and 200 grams. Month 5 (Week 17–20)  Movements become stronger and more varied.  A sleep–wake cycle develops. Foetus is about 30 cm long and 450 grams. Month 6 (Week 21–24)  Eyes fully formed, can open and close.  Foetus can cry.  Chances of survival outside the womb still low (lungs underdeveloped).  Length: 35 cm, Weight: 650 grams. Month 7 (Week 25–28)  Marks the point of viability — baby might survive if born.  Nervous, circulatory, respiratory systems more developed.  Reacts to temperature, smells, tastes, light, and sound.  Length: 40 cm, Weight: 1.2–2.2 kg. Month 8 (Week 29–32)  Fat forms under the skin for temperature regulation.  Physical activity increases.  Length: 45–50 cm, Weight: 2.25–3.15 kg.  Survival rate >90%, but risks remain. Month 9 (Week 33–40)  All systems mature: better heart function, waste removal, immune support (antibodies passed from mother).  Foetus moves into birth position (head-down).  Length: ~50 cm, Weight: 2.8–4.2 kg.  Baby is ready for birth. Foetal Learning  Learning begins in the last 3 months in the uterus.  Foetus responds to sounds, music, language, smells, and tastes.  Can recognise mother’s voice and smell, helping with post-birth bonding.  Stimulates brain and physical development.

Answer 4

* Certain factors may disrupt normal development. Child's physical and mental health and development could be affected. * 50% of congenital abnormalities is caused largely by heredity, followed by prenatal environmental factors or the interaction between environmental or genetic factors. Any external factor or process that has a negative effect on the normal development of an unborn child is known as a teratogen.

Answer 5

1) 2) 3) 4) 5) Time of exposure: Teratogens (harmful substances) do more damage at certain stages of development. The embryo stage is usually more sensitive than the foetal stage. Genetic vulnerability: A mother’s and baby’s genetic makeup affects how badly teratogens impact the baby. Some people are more at risk than others, even with the same exposure. The degree or intensity of the factor: The more the mother uses harmful substances like alcohol or tobacco, the higher the risk to the baby. Each teratogen has a different effect: Each teratogen affects the baby in a specific way. For example, Rubella can cause hearing and heart problems but not limb deformities. Damage is not always evident at birth: Physical problems are seen at birth, but issues like learning or behaviour problems may only show up later.

Answer 6

* Mothers younger than 20 and older than 35 are at a higher risk of giving birth to children with psychological and physical defects * Teen mothers more susceptible to e.g. premature births, still births, and birth problems * Women older than 35 who become pregnant for the first time and women older than 40 tend to have longer and more difficult birth processes o Still births and problems during pregnancy more common o Down’s syndrome tends to increase as she gets older (e older egg cells have a greater risk of defective chromosome division) * Paternal age of higher than about 40 years may increase the possibility of foetal deaths, premature births, low birth weight and certain mental and genetic disorders

Answer 7

* Important that mother follows a healthy and balanced diet as baby obtains nutrition from the mother’s bloodstream via placenta * Link between inadequate diet and various abnormalities * Higher risk of still births, low birth weight, premature births, deformities, stunted growth, death during first year * Undernutrition can produce permanent effects on the size, number of cells, and composition of the child's brain (impact on brain and cognitive development) * Links to various mental disorders * Overnutrition, resulting from excessive or calorie-rich food intake, generally leads to A healthy diet is vital for the development of the unborn child. maternal overweight and obesity that can have adverse consequences for an unborn baby, such as an increased risk for obesity, diabetes, and infant mortality * Paternal obesity is associated not only with an increased incidence of infertility, but also with an increased risk of metabolic disturbances in their offspring

Answer 8

* As demonstrated in World War II as a result of atomic bomb explosions, radiation can result in various abnormalities such as physical deformities, heart diseases, leukemia, stunted growth, intellectual disabilities * Risk of miscarriage and still birth * Exposure to X-rays and other types of radiation may also affect the unborn child adversely because cells in the process of division and differentiation are exceptionally vulnerable to radiation. * The period between about 10 days and 12 weeks after conception is especially high- risk for serious defects, while less serious deviations may occur up to about the twentieth week of pregnancy.

Answer 9

 Most illnesses during pregnancy do not affect the unborn child, as many viruses and bacteria cannot cross the placenta.  However, some agents are small enough to cross the placenta, potentially causing harm to the unborn baby.  Diseases that can be transmitted from mother to child include: o Rubella (German measles) o HIV/AIDS o Syphilis o Herpes simplex (genital herpes)

Answer 10

 Cause: Rubella virus (airborne, spread through coughing/sneezing).  Symptoms: Mild red rash; people often unaware they have it.  Transmission to Baby: o When a woman contracts rubella during pregnancy, especially in the first trimester, the virus can infect the unborn baby. o Can cause Congenital Rubella Syndrome (CRS), which may result in:  Heart defects  Deafness  Blindness  Intellectual disability  Cataracts  Liver and pancreas defects  Miscarriages and stillbirths  Critical Period: o First 3 months: Up to 50% chance of foetal damage. o After 16 weeks: Less risk.  Prevention: o Rubella vaccine (part of MMR) given at 15 months. o Girls may be vaccinated at age 12 to protect future pregnancies. o Women should not be vaccinated during pregnancy due to the live virus. o Natural infection gives lifelong immunity; vaccine-induced immunity weakens over time.

Answer 11

 Cause: Human Immunodeficiency Virus (HIV).  Transmission to Baby: o During pregnancy (placenta) o During birth (contact with mother's blood/fluids) o After birth (breastfeeding)  Without intervention: o Transmission rate: 15%–45% o With treatment: Can be reduced to below 5% o 50% of untreated babies die within 2 years.  Effects: o Weakens immune system, can develop into AIDS. o Associated with malformations and neurological disorders in infants.  Prevalence: o In 2018, around 20% of South African women (ages 15–49) were HIV positive. o Education and prevention programmes have reduced transmission rates.

Answer 12

 Cause: Bacterial infection (STD) spread via direct contact with syphilitic sores.  Transmission to Baby: o Most likely during second half of pregnancy or during childbirth.  Effects on Baby: o Can damage any organ system. o Risk depends on stage of pregnancy and whether mother is treated. o If untreated, outcomes may include:  Miscarriage or stillbirth  Severe anaemia  Skin sores and rashes  Bone damage  Enlarged organs  Intellectual disability  Blindness or deafness  Note: Despite national efforts, syphilis rates are increasing in South Africa.

Answer 13

 Cause: Herpes simplex virus, an STD causing genital sores.  Prevalence: 40%–70% of South African women have it.  Transmission to Baby: o Mostly during birth (through contact with birth canal). o Less commonly through the placenta during pregnancy.  Effects on Baby: o Brain damage o Breathing issues o Seizures o Death  Risk of transmission: 30%–50%

Answer 14

 Golden Rule: Pregnant women should only take medication prescribed by a medical doctor who knows she is pregnant.  Risky Prescription Drugs: o Antidepressants o Antibiotics o Sedatives o Quinine (for malaria)  Possible Effects: o Birth defects o General developmental problems  Over-the-Counter Drugs (e.g., some painkillers, flu medications): o May cause heart defects and blood flow problems in the foetus. o Should be used with caution during pregnancy.

Answer 15

 Harmful Effects on the Foetus: o Premature birth o Miscarriage or stillbirth o Low birth weight o Poor lung function o Visual difficulties o Sudden Infant Death Syndrome (SIDS) o Foetal nicotine/tobacco syndrome: retarded growth, cognitive problems  Mechanism of Harm: o Nicotine crosses the placenta o Blocks oxygen supply o Toxic to foetal development o Present in breastmilk—may cause restlessness and reduced milk intake  Prevalence and Exposure: o ~20% of infants born to smoking mothers show signs of active smoking (cotinine in system) o ~30% show signs of passive smoke exposure o ~50% of pregnant South African smokers continue smoking throughout pregnancy (Amos et al., 2012)  Passive Smoking: o Can impair cognitive and motor development o Paternal smoking may reduce daughters' reproductive lifespan (Fukuda et al., 2011)  E-cigarettes/Vapes: o Still harmful—contain nicotine and other toxic substances o No safe level of nicotine in pregnancy

Answer 16

Foetal Alcohol Syndrome (FAS): o Caused by alcohol abuse or even moderate use during pregnancy o Symptoms:  Cognitive deficits  Slow physical growth  Facial abnormalities (split eyelids, thin upper lip)  Attention problems  Cardiac defects  Below-average height, weight, skull size o Irreversible o One of the main causes of intellectual disabilities o South Africa has the highest FAS prevalence in the world:  Up to 5% prevalence in high-risk areas (Western/Northern Cape)  Safe Alcohol Limit?: o No clear boundary for safe alcohol use o Medical consensus: Avoid alcohol entirely during pregnancy

Answer 17

 Physically Addictive Drugs (e.g., heroin, morphine): o Can cause withdrawal symptoms in newborns:  Respiratory problems  Convulsions  Potential death  Non-physically Addictive Drugs (e.g., marijuana, cocaine, Ecstasy): o Still dangerous o May cause:  Cognitive and neurological deficits  Emotional, behavioural, and academic problems  Additional Considerations: o Many drug abusers also face:  Poverty  Malnutrition  Other teratogens o These factors may also contribute to negative outcomes—but drug use alone has enough evidence for concern

Answer 18

* Mother’s emotions may influence unborn child * Emotions may cause hormones, such as adrenaline, that affect fetal activity, which lasts much longer than mother’s emotions * The mother's emotions, specifically extreme and prolonged stress, may affect her unborn child. This may occur in the following ways: o In reaction to stress, the endocrine glands release hormones such as adrenaline and noradrenaline into the mother's bloodstream. These hormones permeate through the placenta and can reduce the flow of oxygen to the foetus, resulting in in an increased heart rate and activity level. Such increased foetal activity lasts much longer than the mother's emotion. o Stress can weaken a pregnant woman's immune system. This will make her more susceptible to illness, which in turn can harm foetal development. o Pregnant women who experience stress are more likely to smoke, drink alcohol, or use other drugs and medications that could harm their unborn children * Emotional stress may be linked to spontaneous abortions, premature births, low birth weight, difficult deliveries * High maternal stress may affect early development of the brain affecting child’s psychological and physical development in several areas

Answer 19

Natural birth process - Vaginal birth Caesarean birth – C-section

Answer 20

* Delivery of baby through birth canal * Birth process can be divided into 3 stages: 1) Cervix dilates to about 10cm 2) Baby’s head begins to emerge through the cervix and ends when baby is completely outside the mother 3) Placenta and attached membranes (afterbirth) are expelled * Duration varies: The duration of the birth process varies from woman to woman. The average duration, from the first contraction to the expulsion of the afterbirth, is about 14 to 15 hours and covers a spectrum that varies from 24 hours and longer, to as little as three hours or less. * An epidural, usually consisting of an anaesthetic along with a narcotic, which reduces pain in the lower part of the body; a spinal block, consisting of an anaesthetic delivered directly into the spinal cord, which quickly provides pain relief for a brief period.

Answer 21

* Delivery of baby through a surgical incision in the woman’s abdomen and uterus * Usually recommended when labour fails to proceed normally, or when complications occur * Can elect to have a caesarean birth

Answer 22

 General Trend: Most childbirths proceed without major issues.  Global Statistics (World Health Organization, 2019): o ~3 million babies die within the first 28 days of life. o ~3 million babies are stillborn. o ~300,000 women die during pregnancy or childbirth.  Main Cause: o Over 90% of these deaths occur in developing countries due to limited resources and healthcare access. o Many of these deaths are preventable with better medical care.

Answer 23

Anoxia (Lack of Oxygen) Low Birth Weight (LBW)

Answer 24

 Definition: Insufficient oxygen supply to the baby during childbirth.  Synonyms: Asphyxia, hypoxia.  Causes: o Damaged, knotted, or prematurely cut umbilical cord. o Respiratory system malfunction at birth.  Consequences: o Depends on severity and duration. o Severe/prolonged anoxia: brain damage, intellectual disability, cerebral palsy. o Short periods of anoxia: little to no long-term effects, especially with proper postnatal care.  Prevention: o Modern foetal monitoring and adequate prenatal care can reduce the risk of anoxia.

Answer 25

In developed countries: < 2.5 kg o In developing countries: between 1.5 – 2 kg o In South Africa: < 2 kg is the general guideline  Categories: 1. 2. Preterm birth: born before 37 weeks of gestation. Small for gestational age (SGA): growth retardation and often birth defects.  Statistics: o In South Africa (a low-to-middle-income country): ~14% preterm/low birth weight rate. o In high-income countries: ~7%.  Associated Risks: o Higher infant mortality rates. o Increased risk of:  Health issues  Developmental delays  Psychological challenges  Lower intellectual functioning  Positive Outlook: o With a stimulating and supportive environment, many premature/LBW babies catch up by school age.