How does drug use affect pregnancy?

Drug Use During Pregnancy

For the years 2012 and 2013, 5.4 percent of pregnant girls and women age fifteen to forty-four years, including 8.6 percent of women age eighteen to twenty-five years, admitted to some kind of current illicit drug use, according to the Substance Abuse and Mental Health Services Administration.

Certain factors in the life of a drug-abusing woman contribute to her reluctance to seek help, obtain prenatal care, or to stop using drugs during pregnancy. Many women who exhibit a pattern of drug use have mental, social, and financial problems. These situations contribute to an overall unhealthy routine that may include smoking, poor diet, stress, violence, and unpredictable living conditions, resulting in adverse pregnancy outcomes.

Drug-addicted women frequently are much more likely to smoke cigarettes and to use intravenous drugs during pregnancy, potentially exposing themselves to blood-borne infections. The high rates of mental illness in women who abuse drugs and illnesses that include anxiety, depression, and personality disorders contribute to a high rate of relapse among women who attempt to discontinue drug use while pregnant.

Women who abuse drugs may fail to obtain prenatal care for several reasons. For example, amenorrhea is a common side effect of drug abuse, so a woman may not realize she is pregnant. Drug use can be particularly risky to the fetus during the first eight weeks of pregnancy, a critical period of fetal development. Drug addiction also may lead to forgotten or missed appointments or to a lack of concern regarding the health of the fetus. Women who abuse drugs also endanger their own health through unhealthy lifestyles and relationships that may involve physical abuse, which also risks harm to the fetus.

Cocaine

The 1980s witnessed a significant increase in the use of cocaine
and crack cocaine in the United States. Cocaine remains a serious public health issue in the United States, with the majority of cocaine-using women in their childbearing years.

It has been determined that when a pregnant woman uses cocaine, the drug crosses the blood-brain barrier and the placenta, becoming readily available to the developing fetus. Animal models have shown that cocaine interferes with fetal brain development because it interacts with neurotransmitters and affects gene expression, but the mechanisms for this are unknown. Children exposed to cocaine prenatally have demonstrated deficits in attention span and impulse control, which may be attributed to the effects of cocaine on areas of the brain regulating these functions.

Cocaine is known to be a vasoconstrictor and may contribute to spontaneous abortion and low birth weight from a lack of blood flow to the fetus. Cocaine use during pregnancy, especially crack cocaine, has been linked to deformed arms, legs, and internal organs because of this vasoconstriction effect during fetal development. Lack of blood flow across the placenta also prevents the transport of oxygen and nutrients to the fetus. Infants born to cocaine-addicted women also are more likely to be hospitalized in a neonatal intensive care unit.

Infants are also affected indirectly by their mother’s cocaine use through the effects that use has on the area of the brain that controls maternal behavior. Cocaine disrupts the pathways in the brain that control maternal-infant bonding behavior and disrupts the production of oxytocin, a hormone that is key to triggering response behaviors in mothers.

Other Substances

In addition to cocaine, other frequently misused substances, such as methamphetamine, marijuana, hallucinogens, and opiates, have demonstrated increased risk of premature labor and low birth-weight infants. Methamphetamine
use has grown substantially in the United States, particularly in the western half of the country. Thus far, however, there have been few studies of the effect of methamphetamine use on the developing fetus.

It is known that methamphetamine interacts with biochemical transporters in the brain and is transported directly into cells. Once inside nerve cells, methamphetamine disrupts the release and metabolism of neurotransmitter molecules in the brain, impairing the development of the neurotransmitter system. Methamphetamine is a vasoconstrictor, similar to cocaine, and can have the same effect on the fetus through lack of blood flow.

Magnetic resonance imaging studies of children exposed to methamphetamine in utero have revealed abnormal brain structure in association with neurological developmental deficiencies. Newborn babies prenatally exposed to methamphetamine are usually underweight and have shown similar neurological effects as those exposed to cocaine. Animal models have demonstrated learning deficiencies, behavioral problems, and hyperactivity.

Heroin
is a short-acting opiate that, with repeated use and withdrawal, can cause muscle contractions, leading to premature labor. However, no studies have shown that heroin use during pregnancy causes central nervous system damage in the developing fetus. Opiates cross the placenta, so opiate abusers may give birth to addicted newborns who must subsequently undergo withdrawal. These newborns experience irritability, central nervous system difficulties, gastrointestinal disorders, and respiratory symptoms for up to eight days after birth. As in the case of cocaine, it is difficult to determine if these symptoms are caused by the mother’s heroin use or are consequences of other factors associated with the mother’s lifestyle.

Remedial Actions

It is difficult to attribute specific fetal deficiencies to illicit drug use because of the many other confounding factors in the drug-addicted woman’s life. These factors include smoking and poor nutrition, both of which may adversely affect the pregnancy too.

Residential treatment during pregnancy has demonstrated positive outcomes, but it is unclear if this outcome is from stabilization of the drug use or from an overall healthier lifestyle. Studies have shown that drug-addicted women who receive early intervention and extensive prenatal care and supervision can have pregnancy outcomes equivalent to women who do not use drugs. Comprehensive prenatal care can substantially reduce the risk of premature labor and low birth-weight infants among drug abusers.

It is recommended that pregnant women stop using cocaine during pregnancy, but the cocaine must be reduced in a measured fashion to avoid side effects, such as maternal seizures. Methadone treatment has been found to stabilize opiate abusers during pregnancy by allowing the women to gradually diminish opiate abuse through the pregnancy without the repeated use and withdrawal of heroin. The effect of drug abuse on infant mortality remains to be studied and delineated.

Bibliography

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Strathearn, Lane, and Linda C. Mayes. “Cocaine Addiction in Mothers: Potential Effects on Maternal Care and Infant Development.” Annals of the New York Academy of Science 1187 (2010): 172–83. Print.

Substance Abuse and Mental Health Services Administration. Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings. Rockville: SAMHSA, 2014. PDF file.