Have you ever wondered why many medications aren’t studied in pregnant women? Have you noticed that even most over-the-counter medications or supplements carry the warning to “consult with your provider” before using in pregnancy? Did you know that up to 95% of late-stage clinical trials still exclude pregnant women AND is estimated that over 50% of pregnant women take some kind of medication? A recent study calls for change!
But for most medications, we have no idea how they work in pregnant women because we’ve never studied it. And with such little information, some pregnant women choose to err on the side of caution, which could mean suffering through pain, discontinuing antidepressants, and putting themselves at risk of disease.
There are a few reasons for this. First, there’s the fear of harming the fetus. In the 1950s the drug thalidomide was prescribed to pregnant women as a way to treat morning sickness. But after thousands of babies were born with limb deformities, it became clear that medications taken by a pregnant woman posed a risk to the fetus she carried.
This was further emphasized by diethylstilbestrol, a drug once thought to prevent miscarriages and later found to cause vaginal tumors in females exposed to it in the womb. Pregnant women and even women of childbearing age were then explicitly excluded from clinical trials for some time. Once the underrepresentation of women in clinical trials was recognized as a problem and including them in trials became a priority in the 1990s, it was strongly suggested that they either use contraception or abstain from sex while taking part in trials. Currently, up to 95 percent of late-stage clinical trials still explicitly exclude pregnant women.
Other reasons are more financially-based. “The market for pregnant women is much smaller than the general market,” says Costantine. This means drug companies don’t want to take a risk on a smaller slice of the market, especially when there are no regulations in place to protect them from legal action if something went wrong.
If a woman needs a medication while pregnant or was already using one prior to pregnancy, her doctor has to anticipate and measure any potential changes in its therapeutic effect. “For some drugs you follow the concentration in the blood and adjust the doses accordingly,” says Costantine.