The Period of Pregnancy and Prenatal Development

The Period of Pregnancy and Prenatal Development

Infant Mortality

• Number of infants who die during first year of life per 1,000 live births during that year

• 2006: U.S. rate was estimated at 6.7 deaths per 1,000 lived births

• Two thirds of infant deaths occur during the first month after birth

• What accounts for the fact that the United States is behind so many other industrialized countries in the rate of infant mortality?

Genetics and Development

• Variability is guaranteed by the complexity of the human genome and the mechanisms for genetic inheritance

• Human genetics establishes a foundation for appreciating the biological basis of human diversity

Chromosomes and Genes as Sources of Genetic Information

• Chromosomes– Rod-like structures in the nucleus– Store and transmit genetic information

• There are 23 pairs of chromosomes in each human cell

• Sex is determined by whether an X-bearing or a Y-bearing sperm fertilizes the ovum– XX in females, and XY in males

A Small Part of a DNA Molecule

The Principles of Heredity

• Gregor Mendel discovered the laws that govern the process of genetic inheritance– Series of experiments with pea plants in his

monastery garden• Alleles: each gene has at least two states—one

on each chromosome strand in the pair–Homozygous–Heterozygous


• Genotype:– Genetic information about a trait

• Phenotype– Observed characteristic (e.g., eye color, hair color)

• Cumulative relation• Codominance• Dominance



• What is epigenetics?• Sex linked characteristics: genes for specific ‑

characteristics are found on X and Y chromosomes

• Three areas in which genetic determinants contribute to individual variability – The rate of development– Individual traits– Abnormal development

Epigenetic Mechanisms

Sex-Linked Inheritance of Hemophilia

Genetic Technology and Psychosocial Evolution

• Genetic counseling and prenatal diagnosis permit people to make informed decisions about conceiving or carrying a pregnancy to term

• Ethical considerations– Nuclear transplantation

Case Study: Karen and Don

• Reflections– Try to put yourself in the roles of the main

characters in this case: Karen, Don, Karen’s mother, Don’s mother, and Don’s father. How might you react?

– How might these experiences influence how Karen and Don each view their marital relationship?

– What are the ethical considerations in this case?

Your Perspective

• Consider the issues faced by Karen and Don through a cultural lens

• In what ways did their culture influence their attitudes towards pregnancy, childbirth, and abortion?

• In what ways would your culture influence you under similar circumstances?

Gene X Environment Interactionsand Behavior

• Genetics and intelligence– Specific genetic irregularities can cause

degrees of mental retardation– The influence of genetics on intelligence can

be understood through the study of family relationships

Gene X Environment Interactionsand Behavior

The Norm of Reaction

Normal Fetal Development

• Fertilization– Only one sperm can fertilize an ovum– Sperm carry genetic material necessary for

reproduction– Gametes contain only one of each chromosome

• How do twins develop?

Infertility and Alternative Means of Reproduction

• Infertility:– Increases with age– May place great stress on a couple

• What legal and ethical questions have arisen from assistive reproductive technologies (ARTs)?

• Would you consider adoption?

Development in the First Trimester

• The germinal period (weeks 1-2)– After fertilization, the tiny mass of cells (zygote)

travels out of the fallopian tube and implants in the uterine wall


• The embryonic period (weeks 3-8) – Amniotic sac: forms and encloses the developing

organism in amniotic fluid– Placenta: allows nutrients and waste to pass from

the mother to the developing child– The groundwork for all body structures and

internal organs formed– Sensitivity to teratogens: agents that can produce

malformations in the fetus


Critical Periods in Prenatal Development

Development in Second Trimester

• Quickening (approx. 17-20 weeks)– Developing fetus has grown large enough that its

movements can be felt by the mother• Fetus begins to suck and swallow• End of sixth month, sensory receptors of the

fetus are well established

Development in the Third Trimester

• Critical level of neurological maturation in place by 32 weeks

• At the end of the third trimester:– The fetal brain produces hormones

triggering the birth process

The Birth Process

The Birth Process

Caesarean Delivery

• Removing the baby surgically through an incision in the uterine wall– Increased from 5.5% of births in 1970 to 33% in

2010• U.S. Public Health Service calls for a reduction

of the national cesarean rate

The Mother, the Fetus, and the Psychosocial Environment

• What is the impact of the fetus on the pregnant woman?– Changes in roles and social status– Changes in the mother’s emotional state– Fathers’ involvement during pregnancy and

childbirth

Impact of the Pregnant Woman on the Fetus

• Major factors– Poverty– Mother’s age– Maternal drug use– Nicotine– Alcohol– Caffeine– Narcotics

– Prescription drugs– Obstetric anesthetics– Environmental toxins– Mother’s diet

The Cultural Context ofPregnancy and Childbirth

• Reactions to pregnancy– Solicitude versus shame:• Care, interest, and help of others versus shame,

condemnation, and secrecy

– Adequacy versus vulnerability:• Sign of sexual prowess and entrance into social status

versus tiring, exhaustion, and lots of work

The Cultural Context ofPregnancy and Childbirth

• Reactions to childbirth– Every society marks the importance of childbirth

in different ways– Americans focus on:• Safety of the mother and child• Building a sense of competence in the mother and the

father as they approach the care of their newborn

Applied Topic: Abortion

• Termination of a pregnancy before the fetus is able to live outside the uterus– Miscarriage

• Legal and political context of abortion in U.S.– Developmental viability– Fetal viability– Roe v. Wade

Applied Topic: Abortion

• The abortion ratio in the U.S. for 2007 was 19.4 abortions per 1000 women

• What are the characteristics of women who have abortions?– Diverse socioeconomic, developmental, and family

contexts• What is the psychosocial impact of abortion?– Consider men’s reactions to abortion as well

Legal Abortions in the United States

Surrogacy & Classism

• 1.If you were considering hiring a surrogate, how important would her race, education, skin color and class be if she has no genetic relationship to the child for whom you are the intended parent?

• 2 Should the purchase price of genetic material be regulated by the federal government? Do you think there should be limits on how much sperm or how many eggs can be donated by one individual?

• 3 How does the sale and consumption of genetic material differ from other forms of consumption? What ethical concerns do you have about this industry?

• 4 Do you think that children conceived with donated sperm that has been purchased have the right to know the identity of their genetic father when they reach 18? Why or why not?

• 5 Other comments on this issue?

Documents

The Period of Pregnancy and Prenatal Development