The Path of Fetal Development

A developing fetus progresses through three stages of development known as trimesters. Because each trimester is marked by the development of specific organs, an obstetrician can perform a number of tests on a pregnant mother to ensure normal fetal development. However, these tests can only monitor a fetus as it grows and are, therefore, unable to prevent the damage caused by a pregnant mother's substance abuse.

Because the course of a normal pregnancy lasts nine months, each of the three trimesters spans a three-month period. While in week six of the first trimester the embryo's heart starts beating, by week nine the embryo is beginning to develop facial features. The pregnant mother will start to feel the baby move during the second trimester, and, by the third trimester, the fetus has an 85 percent of surviving.

As the fetus develops, the pregnant mother's body endures dramatic physical changes. By week 20 in the second trimester, the increasing size of the uterus puts stress on the mother's internal organs: her lungs, bladder, and other organs will feel pressure.

Throughout the progression of the pregnancy, various tests at different stages can check fetal development. The ultrasound is generally the first test performed in a pregnancy. Best if done early in the first trimester, the ultrasound not only evaluates fetal development but also estimates the delivery date.

Blood tests, also common during pregnancy, are used to measure levels of protein, hCG, and estriol in the mother's blood. Excess levels of protein will indicate chromosomal or possibly neural tube defects. If the blood tests detect any possible abnormalities, then the doctor performs an amniocentesis.

Although an amniocentesis reports results with 99 percent accuracy, it can also trigger miscarriages. However, in most cases, the amniocentesis is a safe procedure.

While normal fetal development can be monitored through various tests, it can also be upset by substance abuse. Most pregnant women are aware that using drugs and drinking alcohol can cause significant birth defects, including fetal alcohol syndrome or mental retardation.

Smoking and consuming caffeine during pregnancy can also put the fetus at risk. Cigarette toxins can cause sudden infant death syndrome, miscarriage, or premature birth. Similarly, because caffeine can also cause birth defects, experts agree that pregnant women should consume no more than one cup of coffee per day.

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