Prenatal
Development begins long before an infant is born. Expectant mothers can feel strong movement and kicking -even hiccupping - inside them during the later stages of pregnancy.
We can also “see” a fetus, which is an unborn infant, sucking their thumb, thanks to new ultra sound techniques.
Prenatal development begins with conception or the union of sperm and egg. The result is a fertilized egg called a zygote and it contains the genotype or the genetic composition of the future person.
The zygote also contains the blue print or phenotype, which contains the observable features of the future person. The fertilized egg begins the germinal stage of development. This stage lasts until the egg implants in the uterine wall and that signals the start of the embryonic stage which lasts until the eighth week after conception.
The zygote is now called an embryo and is only about 1.5 inches long.
After the eighth week the fetal stage begins and the embryo is now called a fetus. At 6 months the fetus can cry, open and close it’s eyes and make a fist. The stage lasts until birth.
Teratogen
The mother’s womb is a very secure place for development to take place. However there are agents called teratogens, which are chemicals and viruses that can reach the developing child and cause harm. One of the most talked about teratogens is alcohol. Its use during pregnancy can result in children that have fetal alcohol syndrome. Alcohol is harmful anytime during the prenatal development and it results in growth retardation, cognitive deficits, and facial deformities.
| Teratogen | Possible Problem | Critical Time |
|---|---|---|
| Cigarettes | Premature birth, lung problems | after 20 weeks |
| Lead | Anemia, mental retardation | throughout pregnancy |
| Rubella (German Measles) | Bleeding Problems | First Months |
| Cocaine | Spontaneous abrotion, neurological probrams | throughout pregnancy |
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