Objective

To characterize the 20 most common prescription medications and the 10 most common prescription medications classified in the former U.S. Food and Drug Administration categories D or X dispensed to pregnant women enrolled in the U.S. Medicaid program.

Methods

We conducted a cohort study of 1,106,757 pregnant women with live births using 2000-2007 Medicaid Analytic eXtract data. We used outpatient pharmacy records to identify medication dispensings and reported the proportion of pregnancies that were dispensed at least one prescription medication. Maternal age and race and ethnicity-stratified estimates were compared using prevalence ratios and 95% confidence intervals (CIs).

Results

During pregnancy, 82.5% of the cohort had a dispensing for one or more prescription medication. The most commonly dispensed medications during pregnancy included nitrofurantoin (21.6%), metronidazole (19.4%), amoxicillin (18.0%), azithromycin (16.9%), and promethazine (13.5%). Proportions were highest among younger women for several medications; eg, nitrofurantoin (23.9% compared with 15.4%; prevalence ratio 1.55, CI 1.52-1.58), metronidazole (20.7% compared with 12.0%; prevalence ratio 1.73, CI 1.69-1.77), and azithromycin (21.1% compared with 11.0%; prevalence ratio 1.93, CI 1.89-1.97) were more common among women younger than 20 years than among women aged 35 years or older. Proportions were highest among white women with some exceptions; eg, compared with white women, metronidazole was more common among black women (29.8% compared with 14.4%; prevalence ratio 2.07, CI 2.05-2.09). Excluding fertility treatments, 42.0% had at least one dispensing for a D or X medication during pregnancy. Codeine (11.9%) and hydrocodone (10.2%) were the most common D medications.

Conclusion

Medications used to treat infections were the most commonly dispensed prescription medications. Dispensing of commonly used prescription medications during pregnancy varied by maternal age and race-ethnicity.

Level of evidence

II.