Increases in Medication Use Found Among Pregnant Women

The wide availability of over-the-counter (OTC) and prescription medications has translated into increased quality of life for many people, but at what cost? During pregnancy, for example, caution and concern is warranted as there is insufficient information about the true risks to the fetus. As a result, some women unintentionally take medications that could potentially harm their fetus, while others experience increased anxiety about relatively safe and effective (and crucial) medications, which may lead to lack of adherence and troublesome outcomes for mother and fetus. As researchers consider initiating studies on the effects of various medications on the fetus, it is important to better understand how often OTC and prescription medications are used during pregnancy.

Recognizing the dearth of data in this field, Dr Allen A. Mitchell, director of Boston University's Slone Epidemiology Center and professor of epidemiology, and colleagues sought to leverage information collected via 2 US multicenter, case-control studies to identify total exposures to any medication (OTC or prescription), with a particular focus on exposures to prescription medications. To do this, Mitchell and colleagues examined data from the Centers for Disease Control and Prevention’s National Birth Defects Prevention Study and the Slone Epidemiology Center Birth Defects Study.

The researchers found that medication use during pregnancy increased over time. Specifically, they found that women on average took 2.5 medications over the course of their pregnancy between 1976 and 1978, but between 2006 and 2008 women took an average of 4.2 medications; this equates to a 68% increase. A similar increase (62.5%) was found regarding the number of medications taken during the first trimester, rising from an average of 1.6 medications to an average of 2.6 medications. More alarmingly, the number of women taking 4 or more medications doubled, with 50.1% of women in the later years reporting use of at least 4 medications. The researchers did not, however, find a difference in use of medications between women who had malformed offspring with those who did not.

The researchers noted that the most commonly used medications had indeed changed over time. Some medications experienced changes in use due to a withdrawal from the market (eg, doxylamine/B6, which accounted for just over 20% of the medications used between 1976 and 1978). Meanwhile, other prescriptions increased with the introduction of new medications that became widely used/prescribed, such as antidepressants. And still other medication trend changes are due to changes in medical guidance. For instance, the recommendation for pregnant women to receive seasonal influenza vaccinations was introduced in 2004, and a resulting increase can be seen. Interestingly, medications such as levothyroxine, progesterone, and ampicillin/amoxicillin were commonly used throughout the 33-year study period. The most commonly used medications between 2004 and 2008 can be found in the Figure.

Figure. Most commonly used medications (2004-2008). Click to open full size

Overall, Mitchell and colleagues believe their work emphasizes the need for ongoing surveillance regarding medication use in pregnancy as well as the consequences of their use. “These data reflect the widespread and growing use of medications by pregnant women and reinforce the need to study their respective fetal risks and safety,” they concluded.

More Information

CDC:Medications and pregnancyACOG Guidelines on Psychiatric Medication Use During Pregnancy and Lactation

References:

Reference
Mitchell AA, Gilboa SM, Werler MM, et al. Medication use during pregnancy, with particular focus on prescription drugs: 1976-2008. Am J Obstet Gynecol. 2011; 205:51.e1-8.