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Pregnancy and Prenatal Development
Chapter 4
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Guideposts for Study
1. What are the three stages of prenatal development, and what happens during each stage?
2. What environmental influences can affect prenatal development?
3. What techniques can assess a fetus’s health and well-being, and what is the importance of prenatal and preconception care?
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Prenatal Development: Three Stages
Gestation – the period between conception and birth
Gestational age – the age of an unborn baby, usually dated from the first day of an expectant mother’s last period
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Prenatal Development: Three Stages
Cephalocaudal Principle
Growth occurs from head and downward
Proximodistal Principle
Development occurs from the center of body and outward
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Prenatal Development: Three Stages
3 Stages of Prenatal Development
Germinal
Embryonic
Fetal
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Prenatal Development: Three Stages
Germinal Stage (Fertilization to 2 Weeks)
Zygote divides, becomes more complex, and is implanted in the wall of the uterus
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Prenatal Development: Three Stages
Embryonic Stage (2 to 8 Weeks)
Organs and major body systems-- respiratory, digestive, and nervous--develop rapidly
A critical period in development
Spontaneous abortion
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Mourning a Miscarriage or Stillbirth
Methods differ from culture to culture
Some do’s and don’ts
Do: bring up the subject, listen with empathy, express sadness and regret, allow people to cry
Don’t: minimize the loss or pain, ask why it happened, expect the process to take time
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Prenatal Development: Three Stages
Fetal Stage (8 Weeks to Birth)
Fetus grows rapidly to about 20 times its previous length, and organs and body systems become more complex
Ultrasound detects fetal movement
Fetal learning and memory
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Prenatal Development: Environmental Influences
Maternal Factors
Teratogens –Environmental agents that can interfere with normal prenatal development
Examples include: a virus, drug, radiation, pollution
Nutrition and Maternal Weight
Folic Acid
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Prenatal Development: Environmental Influences
Maternal Factors Malnutrition
Physical Activity and Strenuous Work
Drug Intake Medical drugs
Alcohol (Fetal Alcohol Syndrome)
Nicotine
Caffeine
Marijuana and cocaine
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Prenatal Development: Environmental Influences
Maternal Factors
HIV/AIDS
Perinatal transmission
Other maternal factors
Infections Toxoplasmosis
Thyroid deficiency
Rubella
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Prenatal Development: Environmental Influences
Maternal Factors
Maternal stress
Maternal age
Outside environmental hazards
Air pollution
Chemicals
Radiation
Extreme heat and humidity
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Prenatal Development: Environmental Influences
Paternal Factors Lead
Marijuana or tobacco smoke
Large amounts of alcohol or radiation
DES
Pesticides
High ozone levels
Damaged or deteriorated sperm
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Monitoring and Promoting Prenatal Development
Noninvasive Procedures
Ultrasound
Blood tests
Disparities in Prenatal Care
Increasing multiple births
Benefits of prenatal care are not evenly distributed
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Monitoring and Promoting Prenatal Development
The Need for Preconception Care
Physical Examinations
Vaccinations
Risk Screening
Counseling to avoid smoking and alcohol, and maintaining healthy weight and nutrition