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MODULE2.2-6PrenatalSP20.pptxAn Orientation to Lifespan Development
Lesson #6
The Prenatal Period
Module 2.2 Prenatal Growth and Change
The Moment of Conception and the Onset of Development
LO 2.7 Explain the process of fertilization and the three stages of development.
Fertilization occurs when the sperm and ovum join to form a new cell.
The Germinal Stage: Fertilization to 2 Weeks
Cell division
Baby is a zygote
Cells form protective layer
Placenta provides nourishment and oxygen
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Anatomy of the Female Reproductive Organs
The basic anatomy of the female reproductive organs is illustrated in this cutaway view.
Source: Based on Moore & Persaud, 2003.
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The Moment of Conception and the Onset of Development
LO 2.7 Explain the process of fertilization and the three stages of development.
The Embryonic Stage: 2 to 8 Weeks
Baby called an embryo
Baby composed of three layers:
Ectoderm: Outer layer, forms skin, hair, teeth, sense organs, brain, and spinal cord
Endoderm: Inner layer, produces digestive system, liver, pancreas, and respiratory system
Mesoderm: Middle layer, forms muscles, bones, blood, and circulatory system
Brain undergoes rapid growth
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The Moment of Conception and the Onset of Development
LO 2.7 Explain the process of fertilization and the three stages of development.
The Fetal Stage: 8 weeks to Birth
Baby called a fetus
Dramatic increase in size and weight
Organs become differentiated and operational
Brain becomes increasingly sophisticated
Hemispheres grow rapidly
Neurons become coated with myelin
By 3 months, fetus swallows and urinates; by 4 months, mother can feel movement
In weeks 8 to 24, hormones begin the differentiation that results in male or female fetus
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Embryo and Fetus
(a) Embryo at 5-6 weeks. (b) Fetus at 8 weeks. (c) Fetus at 14 weeks.
Body Proportions
During the fetal period, the proportions of the body change dramatically. At 2 months, the head represents about half the fetus, but by the time of birth, it is one-quarter of its total size.
Pregnancy Problems
LO 2.8 Describe some of the physical and ethical challenges that relate to pregnancy.
Infertility:
Is the inability to conceive after trying 12 to 18 months
About 15 percent of couples will have problems
Causes
Age of parents
Previous use of birth control, illicit drugs, or cigarettes
Men who have low sperm count
Woman’s mother taking certain drugs during pregnancy
Most common cause: Failure to ovulate
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Older Women and Risks of Pregnancy
Not only does the rate of infertility increase as women get older, but the risk of chromosomal abnormality also increases.
Source: Reproductive Medicine Associates of New Jersey, 2002.
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Pregnancy Problems
LO 2.8 Describe some of the physical and ethical challenges that relate to pregnancy.
Infertility:
Treatments
Artificial insemination
Intracervical insemination (ICI)
Intrauterine insemination (IUI)
In vitro fertilization (IVF)
Intrafallopian transfer (GIFT)
Zygote intrafallopian transfer (ZIFT)
Sometimes a surrogate mother used
Pregnancy rates as high as 48 percent; live births lower
Ethical considerations
ARTIFICIAL INSEMINATION is a process of fertilization in which a man’s sperm is placed directly into a woman’s vagina by a physician. The most common type is intracervical insemination.
IN VITRO FERTILIZATION (IVF) is a procedure in which a woman’s ova are removed from her ovaries, and a man’s sperm are used to fertilize the ova in a laboratory.
Gamete intrafallopian transfer (GIFT) and Zygote intrafallopian transfer (ZIFT) are procedures in which an egg and sperm or fertilized egg are implanted in a woman’s fallopian tubes.
IVF is becoming more successful, with pregnancy rates as high as 48 percent for women under age 35.
Actual live births are less than pregnancy rates because not all pregnancies ultimately result in birth.
Surrogate mother is a woman who agrees to carry the child to term; may be used in cases where the mother is unable to conceive.
Ethical issues include the use of surrogate mothers, in vitro fertilization, and sex selection techniques
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Pregnancy Problems
LO 2.8 Describe some of the physical and ethical challenges that relate to pregnancy.
Miscarriage and Abortion
Miscarriage is spontaneous abortion
Pregnancy ends before child is viable
15 to 20 percent of pregnancies end in miscarriage
Many times mother not aware of pregnancy
Usually due to genetic abnormality
Women who suffer miscarriages experience anxiety, depression, and grief
Depression rates for women who have had a miscarriage remain high
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Pregnancy Problems
LO 2.8 Describe some of the physical and ethical challenges that relate to pregnancy.
Miscarriage and Abortion
Abortion is voluntary termination of pregnancy
About one in five pregnancies end in abortion worldwide
Decision to abort is difficult
Physical, psychological, legal and ethical issues may arise
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The Prenatal Environment: Threats to Development
LO 2.9 Describe the threats to the fetal environment and what can be done about them.
Teratogen: Environmental agent such as virus or chemical that produces a birth defect
Impact of teratogens depend on when they occur
Different organ systems are vulnerable at different times
Mother’s Diet:
Important in supporting development of fetus
High-nutrient diet leads to fewer complications
Diet is immense concern worldwide
The Prenatal Environment: Threats to Development
LO 2.9 Describe the threats to the fetal environment and what can be done about them.
Mother’s Health:
Illness can cause devastating consequences:
Rubella
Chicken pox
Syphilis and gonorrhea
AIDS
Mental health
Rubella (German measles) prior to the 11th week can cause blindness, deafness, heart defects, or brain damage.
Chicken pox and mumps may cause birth defects and miscarriage, respectively.
Syphilis and gonorrhea can be transmitted to the child.
Babies born with AIDS (acquired immune deficiency syndrome) can have birth abnormalities including small, misshapen faces, protruding lips, and brain deterioration.
A mother’s mental health can affect her children. For example, if the mother suffers from clinical depression while she is pregnant, the development of her children might be negatively affected.
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The Prenatal Environment: Threats to Development
LO 2.9 Describe the threats to the fetal environment and what can be done about them.
Mother’s Drug Use:
Legal and illegal drugs pose risk
Legal drugs
Aspirin can lead to fatal bleeding
DES (Diethylstilbestrol (DES) is a synthetic form of the female hormone estrogen) - later caused cervical and vaginal cancer in daughters
Illegal drugs
Marijuana restricts oxygen
Cocaine restricts oxygen and blood flow
Babies are born addicted
Babies shorter and weigh less
Babies have serious respiratory problems and birth defects
Often they are impossible to soothe
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The Prenatal Environment: Threats to Development
LO 2.9 Describe the threats to the fetal environment and what can be done about them.
Mother’s Use of Alcohol and Tobacco:
Small amounts can impact fetus
Alcohol
Fetal alcohol spectrum disorder (FASD)
Fetal alcohol effects (FAE)
Two drinks a day has been associated with lower intelligence
Tobacco Use
Reduces oxygen and increases carbon monoxide
Babies can miscarry or be born low birth weight
Babies are shorter and 50 percent more likely to have intellectual disability
FETAL ALCOHOL SPECTRUM DISORDER (FASD) is a disorder caused by the pregnant mother consuming substantial quantities of alcohol during pregnancy, potentially resulting in mental retardation, delayed growth, and facial deformities.
Even smaller amounts of alcohol can produce FETAL ALCOHOL EFFECTS (FAE), a condition in which children display some, although not all, of the problems of FAS due to their mother’s consumption of alcohol during pregnancy.
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The Prenatal Environment: Threads to Development
Mother’s Age:
Mothers over 30 have greater risk of complications:
Premature birth
Low birth weight
Down syndrome
Infant mortality
The Prenatal Environment: Threats to Development
LO 2.9 Describe the threats to the fetal environment and what can be done about them.
Do Fathers Affect the Prenatal Environment?
Secondhand smoke
Alcohol and illegal drug use can lead to chromosomal damage at conception
Stress may be unhealthy for mother
Sperm damage from environmental toxins
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Becoming an Informed Consumer of Development: Optimizing the Prenatal Environment
Optimizing pregnancy
Planning
Schedule nonemergency X-rays only during first 2 weeks after menstrual periods
Get vaccinations 3 months before getting pregnant
Discontinue birth control pills 3 months before pregnancy
Eat well before and during pregnancy
Don’t use alcohol or other drugs
Monitor caffeine intake
Don’t smoke
Exercise regularly
Review: Prenatal Growth and Change
Fertilization joins the sperm and ovum.
The germinal stage is fertilization to two weeks.
The embryonic stage is 2 to 8 weeks.
During the embryonic stage, the ectoderm, mesoderm, and endoderm grow and specialize.
The fetal stage is 8 weeks to birth.
The fetal stage is characterized by rapid increase in complexity and differentiation of organs.
Review: Prenatal Growth and Change
Some couples need medical aid to conceive.
Options for infertility include IVF and artificial insemination.
A teratogen is a drug, chemical, or virus that produces birth defects.
Factors in the mother that can affect the unborn fetus are diet, age, and illness and drug, alcohol, or tobacco use.
The behaviors of fathers can affect the health and development of an unborn child.
Applying Lifespan Development
Studies show that “crack babies” who are starting school have significant difficulty dealing with multiple stimuli and forming close attachments. How might both genetic and environmental influences have combined to produce these results?
