Copyright © 2009 Pearson Education Canada4-1 Chapter 4: Prenatal Development and Birth 4.1 From Conception to Birth 4.2 Influences on Prenatal Development 4.3 Happy Birthday! MODULES

Copyright © 2009 Pearson Education Canada4-2 Module 4.1 Conception to Birth LEARNING OBJECTIVES Recount what happens to a fertilized egg in the first two weeks after conception. Describe when body structures and internal organs emerge in prenatal development. Note when body systems begin to function well enough to support life.

Copyright © 2009 Pearson Education Canada4-3 Period of the Zygote Begins when egg is fertilized in the fallopian tube. Period of rapid cell division. Ends 2 weeks later when the zygote is implanted in the wall of the uterus.

Copyright © 2009 Pearson Education Canada4-4 Period of the Zygote Germ disc: a small cluster of cells near the zygote’s center that develops into a baby. Placenta: a uterine structure for exchanging nutrients and wastes between mother and baby.

Copyright © 2009 Pearson Education Canada4-5 Period of the Embryo From 3 to 8 weeks after conception. Body parts are formed during this period -Ectoderm -Mesoderm -Endoderm Embryo rests in the amnion filled with amniotic fluid. Umbilical cord joins embryo to placenta.

Copyright © 2009 Pearson Education Canada4-6 Period of the Fetus From 9 weeks after conception to birth. Increase in size and systems begin to function - Cephalocaudal -Proximodistal Age of viability: 22 to 28 weeks.

Copyright © 2009 Pearson Education Canada4-7 Module 4.2 Influences on Prenatal Development LEARNING OBJECTIVES Explain how prenatal development is influenced by a pregnant woman’s nutrition, the stress she experiences while pregnant, and her age. Define what a teratogen is, and state what specific diseases, drugs, and environmental hazards can be teratogens. Detail exactly how teratogens influence prenatal development. Summarize how prenatal development can be monitored and how abnormal prenatal development can be corrected?

Copyright © 2009 Pearson Education Canada4-8 General Risk Factors Nutrition: adequate amount of food, protein, vitamins, & minerals. -Folic acid and spina bifida. Stress: decreases oxygen to fetus and weakens mother’s immune system. -Workplace stress. Mother’s Age: neither too young, nor too old. -More women are having babies after the age of 30.

Copyright © 2009 Pearson Education Canada4-9 Teratogens: Diseases, Drugs, and Environmental Hazards Thalidomide ( Many diseases pass through the placenta directly and attack the fetus. Potentially dangerous drugs not limited to cocaine but include alcohol and caffeine. -Fetal alcohol spectrum disorder (FASD) Environmental hazards are treacherous because we’re often unaware of their presence.

Copyright © 2009 Pearson Education Canada4-10 How Teratogens Influence Prenatal Development Not universally harmful.The impact of a teratogen depends upon the genotype of the organism. The impact of teratogens changes over the course of prenatal development. Each teratogen affects a specific aspect (or specific aspects) of prenatal development. Damage from teratogens is not always evident at birth but can appear later in life.

Copyright © 2009 Pearson Education Canada4-11 Effects of Teratogens

Copyright © 2009 Pearson Education Canada4-12 Prenatal Diagnosis and Treatment Diagnosis: ultrasound, amniocentesis, and chorionic villus sampling (CVS) can detect physical deformities and genetic disorders. Treatment: fetal medicine and genetic engineering are experimental (PKU).

Copyright © 2009 Pearson Education Canada4-13 Prenatal Diagnosis Amniocentesis Chorionic Villus Sampling

Copyright © 2009 Pearson Education Canada4-14 Module 4.3 Happy Birthday! LEARNING OBJECTIVES List the stages in labour and delivery. Describe “natural” ways of coping with the pain of childbirth and state under what circumstances childbirth at home might be safe. Summarize how we determine whether a baby is healthy and what behavioral states are common in newborns. Identify some complications that occur during birth. List the characteristics of postpartum depression and its effects.

Copyright © 2009 Pearson Education Canada4-15 Labour and Delivery Stage 1: starts when the muscles of the uterus contract and ends when the cervix is fully enlarged (about 10 cm). Stage 2: baby is pushed down the birth canal. -Crowning - Breech presentation Stage 3: placenta is expelled.

Copyright © 2009 Pearson Education Canada4-16 Approaches to Childbirth Childbirth classes provide information and teach pain control through deep breathing, imagery, and supportive coaching. Mothers who attend classes use less medication during labour and feel more positive about labour and birth. In the last 40 years, many Canadian women have used more “natural” or prepared approaches to childbirth, viewing labour and delivery as life events to be celebrated, rather than a medical procedure to endure. 3% of Canadian families chose to have babies at home with the help of a midwife.

Copyright © 2009 Pearson Education Canada4-17 Birth Complications Lack of oxygen (anoxia): Often leads to surgical removal of the fetus (C-section). Placental abruption can also lead to hypoxia. Premature and Small-for-date infants. Prematurity is less serious than small-for-date. Low birth weight can result in infant mortality.

Copyright © 2009 Pearson Education Canada4-18 The Newborn Assessing the newborn: Apgar to assess newborns’ health; NBAS for a comprehensive assessment of infants. 4 primary states: alert inactivity, waking activity, crying, sleeping. Half of newborns’ sleep is REM (i.e. stimulation of the infant’s brain). Sleeping on one’s back may prevent SIDS.

Copyright © 2009 Pearson Education Canada4-19 Postpartum Depression Half of all new moms feel some irritation, resentment, and crying % feel more severe postpartum depression. Maternal postpartum depression is characterized by feelings of low self-worth, disturbed sleep, poor apathy and appetite. Postpartum depression affects warmth and enthusiasm of mothering.

Copyright © 2009 Pearson Education Canada4-20 Conclusions All new mothers need support from family and friends. Postpartum depression must be treated. Children of depressed mothers are at an increased risk of developing depression and behavioral problems.