Pregnancy comes with unique health risks and considerations, but pregnant people also continue to experience the same health problems that nonpregnant people do. Despite this, a new study has found that fewer than 1% of randomized controlled trials in the U.S. include pregnant participants.
The study was published in the American Journal of Obstetrics and Gynecology on Jan. 3 and was announced in a Jan. 21 press release.
Out of 90,860 drug trials involving reproductive-age women from the last 15 years, only 0.8% included pregnant participants. What’s more, about 75% of the studies explicitly excluded pregnant people from participating.
Excluding pregnant people from trials "slows down the use of beneficial medications because doctors and pregnant people are hesitant to use drugs when there is limited safety data available," study author Alyssa Bilinski, Ph.D., a health policy researcher at Brown University, told Fierce Biotech in an email. "Conversely, when a medication is harmful, more people likely experience adverse effects before the problem is discovered because not all individuals taking the medication are studied."
Most of the trials that did include pregnant people were for pregnancy-specific conditions, like preventing preterm birth, preeclampsia and pregnancy-related symptoms like nausea.
“We found only 19 trials for non-infectious chronic conditions like anxiety, depression and asthma that have included pregnant participants,” Bilinski said in the press release.
Several tactics to increase pregnant patient participation in trials have been proposed by committees from the National Academies of Science, Engineering and Medicine and an FDA task force, Bilinski said. These include "adjusting grant funding and timelines to account for challenges in working in this setting, improving communication to address liability concerns and changing classification of pregnant individuals as vulnerable in some review processes."
In their paper, Bilinski and co-author Natalia Emanuel, Ph.D., an economist at the Federal Reserve Bank of New York, call for more randomized controlled trials that include pregnant patients. In the release, Bilinski pointed out that trials were only required to include women at all in 1993.
“That really wasn’t that long ago,” Bilinski said. “Our hope is that 30 years from now, lacking high-quality evidence about medication safety during pregnancy will seem as strange and outdated as excluding women from trials seems to us today.”
The two are now working on a paper about the health effects of excluding pregnant patients from trials, Bilinski said, using case studies like the COVID-19 vaccines and thalidomide, which was once used for treating morning sickness before it was discovered to cause serious birth defects.
Editor's note: This story has been updated to include additional information from the study author.