It is important for a woman to stay healthy during pregnancy, for her own well-being as well as for her newborn. Substance abuse during pregnancy may harm her own health, as well as interfere with her ability to support the pregnancy and can directly impair prenatal development.
How Drugs Affect a Fetus
Virtually all drugs pose a threat to pregnant women. Illegal drugs, legal substances (such as alcohol and tobacco), and even medical drugs, both prescription and over-the-counter, can be harmful. About two to three percent of all birth defects result from the use of drugs other than alcohol. Drug abuse during pregnancy is so dangerous because of how the drugs reach the fetus. These substances cross the placenta to the fetus, taking the same route as oxygen and nutrients, which fuel the fetus’s growth and development.
The effects of drug abuse during pregnancy are dependent on the stage of development of the fetus as well as the strength and dose of the drug. Within twenty days after fertilization, the fetus is highly resistant to birth defects, but between the third and eighth week, the fetus becomes particularly vulnerable to birth defects. Drugs taken after the completion of organ development are unlikely to cause birth defects but may alter the growth and function of normally formed organs and tissues.
The Food and Drug Administration (FDA) classifies drugs according to the degree of risk they pose for the fetus if ingested during pregnancy.
Alcohol abuse in the first trimester in pregnancy, along with drug use, interferes with most of the formation of body organs and systems of the fetus. During this stage drugs and alcohol can cause malformations to develop in areas such as the heart, the limbs, and the face.
After about the tenth week, the fetus grows rapidly in weight and size. Drug use at this time can still damage developing organs, such as the eyes and the nervous system. Continuing to use drugs dramatically increases the risk of miscarriage and premature delivery. The greatest danger drugs pose at this stage is their potential to interfere with normal growth. Intrauterine growth retardation (IUGR) is likely to result in a low-birth weight baby.
How Drinking Affects Pregnancy
Consuming alcohol during pregnancy is the leading known cause of birth defects, especially during the early weeks. In the mother’s body, alcohol breaks down chemically to a cell-damaging compound that is readily absorbed by the fetus. Heavy drinking during early pregnancy will greatly increases the risk of Fetal alcohol syndrome, a cluster of birth defects. The amount of alcohol required to cause fetal alcohol syndrome is still unknown, but pregnant women are advised to abstain from drinking alcohol at all. Heavy drinking later on in pregnancy may also hinder growth.
Fetal alcohol syndrome (FAS) is one of the most serious consequences of drinking during pregnancy. It occurs in about 2 of 1,000 live births. The syndrome includes inadequate growth before or after birth, facial defects, a small head, mental retardation, and abnormal behavioral development. Apart from physical defects, severe behavioral problems may occur, including antisocial behavior and attention deficit disorder.