Aug. 10, 2015 -- Although most doctors say prescribing drugs to pregnant women is a complex issue, they still prescribe them frequently.
More than 4 out of 5 moms-to-be were given an Rx for at least one medication, and 42% were prescribed a drug that could harm a developing fetus, researchers found in a large study.
The research, which details the type and timing of meds prescribed to pregnant Medicaid patients, presents a disturbing pattern, according to Kristin Palmsten, ScD, from the University of California, San Diego, and colleagues. They published the results of the study online and in the September issue of Obstetrics & Gynecology.
Palmsten and colleagues found the most commonly prescribed medications are those used to treat infections. They also report that Rx meds are more commonly given to younger pregnant women and white women.
The researchers looked at data for women enrolled in Medicaid before pregnancy. Their analysis included over-the-counter medications given out by a pharmacist, but not meds purchased over the counter directly or prescribed during hospitalizations.
The most commonly prescribed drugs were the antibiotics amoxicillin, azithromycin, metronidazole, and nitrofurantoin, along with promethazine, which is used to treat allergy symptoms, nausea and vomiting, and motion sickness. Other frequently dispensed meds include the antibiotic cephalexin and codeine with acetaminophen.
Drugs That May Cause Harm
Palmsten and her colleagues also found that 42% of moms-to-be filled a prescription for a category D or X drug during pregnancy. The categories were assigned by the FDA. They are no longer used.
Category D means there is evidence a drug poses a risk to a fetus. The top five most commonly prescribed category D drugs were codeine, hydrocodone, hydrocortisone, ibuprofen, and the antibiotic sulfamethoxazole.
Category X drugs have been tested in animals or humans, and they've been found to cause problems with the fetus. The five most commonly prescribed ones were hormonal contraceptives, the cholesterol-lowering drugs atorvastatin and simvastatin, the insomnia drug temazepam, and the blood thinner warfarin.
Many of the most commonly dispensed medications have limited or low-quality data available regarding safety during pregnancy, the researchers say.
As of June 30, the FDA has changed the way it labels prescription medications for use in pregnancy and breastfeeding. The new labels will include a summary of the risks of the drug during pregnancy.
The Pharmacoepidemiology Program at the Harvard School of Public Health (with which several of Dr. Palmsten's colleagues are affiliated) is partially supported by training grants from Pfizer, Takeda, Bayer, and Phrma.