Effects of Drugs Taken During Pregnancy

Various types of medications and drugs can have serious and potentially lethal effects on the development of a fetus. According to PBWorks.com, a website advocating safe practices during pregnancy, “Roughly 1 in 33 babies in the United States (120,000 babies) are born with birth defects each year.” Sadly, a significant percentage of these cases are inflicted either by environmental toxins or neglectful behaviors on the part of the mother. During the gestation period, which extends from the moment of conception to birth, any harmful chemicals ingested by the mother can slowly enter the placenta and negatively affect the unborn child (however some medical professionals believe the fetus is independent of the mother’s nutrients until about two weeks into pregnancy, so consuming small amounts of alcohol during that time is permissible). Women who consume illegal or legal drugs (such as alcohol or tobacco) during pregnancy are at an increased risk for complications, including premature labor and delivery. These women are also more likely to experience a miscarriage or stillbirth. The greater the intensity and extent of the drug-use, the more likely there will be adverse effects. The timing of the drug intake also corresponds with the severity of the fetal damage; for example, between 4 and 8 weeks after conception, drugs and alcohol are more likely to increase the risk of spontaneous abortions and physical malformations of the child versus later on in pregnancy. Consuming harmful chemicals after the eighth month of gestation is often associated with retarded growth, prematurity, low birth weight, and neurological damage. Drugs and medications that should be avoided are discussed in detail below.


Long-term use of prescription antibiotics during pregnancy may cause damage to the developing fetus. Bhakti Satalker explains, “The antibiotics safe to take during pregnancy are the most common ones like penicillin, cephalosporins and erythromycin… [However] it is important that you take your multivitamin dose daily (Buzzle.com)”. An example of a harmful antibiotic, Accutane, which is used as a curative method for acne, may also cause severe birth defects if taken while pregnant. Nitrofurantoin, a drug particularly effective in treating urinary tract infections, may cause jaundice (yellowing of the skin) in newborn children. Tetracycline may cause the child to have stained, discolored teeth and bone abnormalities. Gentamycin, kanamycin, neomycin, streptomycin, and vancomycin (a family of antibiotics that fight off various bacterial infections) may cause deafness and other fetal deformations. However safe and beneficial a prescription may appear, it is crucial that you consult your gynecologist or obstetrician before beginning or continuing an antibiotic regime while pregnant.


Alcohol consumption during pregnancy is detrimental to a fetus' health. Alcohol consumed by a pregnant woman is absorbed by the placenta and directly affects the fetus within, leading to a variety of malformations and fetal disorders known collectively as Fetal Alcohol Syndrome (FAS). The characteristics of Fetal Alcohol Syndrome consist of:

  • Mental retardation
  • Problems with speech, thinking, & social skills
  • Prenatal and postnatal growth deficiencies
  • Narrow, small eye openings
  • Small head
  • Undersized Jaw & upper lip
  • A small, underdeveloped brain
  • Joint, limb, and heart malformations
  • Poor coordination & decreased muscle tone

According to the U.S. National Library of Medicine, there is no “safe” level of alcohol consumption while a woman is pregnant. Alcoholic substances can seriously damage the development of the unborn child both physically and cognitively, although some doctors argue that a glass of wine is acceptable every once in a while. Still, the safest choice for both the mother and child is to abstain from alcohol altogether. Heavy alcohol use seems to be the most detrimental during the first three months of gestation.


Cocaine use during pregnancy also may have devastating effects on the health and well being of the child, both inside and out of the womb. Most commonly, it can lead to premature birth and low birth weight. Drug use (and smoking cigarettes) can cause the placenta to disconnect from the uterine wall prematurely, a condition known as placental abruption. This situation can result in “extensive blood loss” and could be fatal for the child and/or the mother. Using cocaine can also lead to physical ailments in the child such as microcephaly, a condition in which the brain has stopped growing and has resulted in an undersized skull circumference. According to the National Institute of Neurological Disorders, “Depending on the severity of the accompanying syndrome, children with microcephaly may have mental retardation, delayed motor functions and speech, facial distortions, dwarfism or short stature, hyperactivity, seizures, difficulties with coordination and balance, and other brain or neurological abnormalities.” It is also reported these babies are more irritable and have trouble sleeping, which can be considered somewhat of a “withdrawal” phase from the drug. At 18 months, they have difficulty focusing their attention and may have more behavioral problems as they age.


Synthetic hormones, such as progestin, can cause a female fetus to become masculinized. Some studies show that corticosteroids are linked with low birth weight, stillbirth, and physical distortions like cleft palate. Excessive amounts of vitamin A, vitamin D, B6, and K have been linked with fetal defects and cleft palate. Diethylstilbestrol (DES), a potent estrogen, has been shown to cause vaginal cancer in the females whose mothers used the steroid during pregnancy. Long-term exposure to DES is also linked to low birth weight.

Other Drugs

The U.S. Public Health Service warns that maternal cigarette smoking causes low birth weight, increased incidence of premature birth, and stunted fetal growth. Some antihistamines may cause malformations in the fetus, while even the most common medications, like aspirin, may cause blood complications. The psychoactive chemical in marijuana is able to cross the placental barrier and inhibit ovulation, thus making conception more difficult. Researchers in Canada conducted a study comparing the fetal health of women who used marijuana versus pregnant nonusers. According to the study, there were no differences between the two groups in terms of miscarriage, complications during birth, or incidence of birth defects. However, the infants of the marijuana users had more tremors and visual problems during their preschool years. Lower scores on intelligence tests and poor task performance have also been reported in six-year-olds who had been exposed to marijuana. Certain medications prescribed for depression/anxiety disorders (Celexa, Zoloft, Paxil, etc.) can cause heart-related complications for the fetus. X-rays can also damage the baby, so be sure to notify your technician that you are pregnant before partaking in any x-raying process. Risk of damage is particularly high during the first 42 days after conception.

Dads and Drugs

Little research has been done on the effects of a man's drug use on a fetus. However, drugs taken by men before conception can damage the sperm and their genetic contents, thus creating harm for future fetal developmet. Studies have shown that an increased risk of birth defects and childhood cancer occurs when a father smokes cigarettes even when the mother does not. Future research must be conducted in order to clarify any other effects a father's use of drugs has on his children.


Last Updated 20 February 2013.

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