A serious drug shortage calls into question the exclusion of pregnant women in clinical trials

Australian mothers and babies are at risk due to a lack of several vital medicines considered safe for use in pregnancy. Shortages are said to be due to manufacturing and distribution problems, with high blood pressure drugs such as prazosin, clonidine and nifedipine particularly affected. These blood pressure medications are critical to preventing the effects of uncontrolled, severe pregnancy blood pressure, which can lead to death, and even acute hypertension, which can lead to strokes and brain hemorrhages. Another important need for these drugs is to prevent preeclampsia, a dangerous blood pressure-related pregnancy disorder that affects the arteries that carry blood to the placenta and has lasting consequences for mother and baby.

There are only six drugs registered in Australia to treat high blood pressure in pregnancy and all are over 30 years old and therefore long past their patent expiry, meaning pharmaceutical companies can make minimal profits. In turn, many have chosen to stop distribution. This raises the question of whether more needs to be done to encourage pharmaceutical companies to maintain supplies of older, off-patent medicines, as the lack of distribution and manufacturing by pharmaceutical importers is putting lives at risk. However, no branch of government is responsible for ensuring the supply of such drugs, which is why obstetric experts in the Medical Journal of Australia have proposed a call to action for the federal government to create a publicly funded facility in hopes of ensuring a stable supply of treatments for pregnancy-related conditions such as preeclampsia, postpartum hemorrhage and nausea.

This call to action was supported by the Royal Australian and New Zealand College of Obstetricians and Gynecologists. The systematic exclusion of pregnant women from clinical trials of new drugs is evident when one considers that there are only six outdated drugs used to treat high blood pressure that are suitable in pregnancy, compared to the more than 50 drugs used for high blood pressure in available to the non-pregnant population. This is due to legitimate concerns about the potential effects of medication on pregnant women following the thalidomide tragedy, in which thalidomide was used to treat nausea in pregnant women but resulted in serious birth defects in thousands of children. However, the fear of history repeating goes too far in the opposite direction, leaving pregnant women largely excluded from legal proceedings.

According to GlobalData's Trial Intelligence Platform, 4% of clinical trials initiated worldwide in 2024 include pregnant women in their inclusion criteria, while 36% include pregnant women in their exclusion criteria. The remaining 60% will not have pregnancy mentioned in their inclusion or exclusion criteria. In addition, the data also suggests that the proportion of studies whose exclusion criteria include pregnant women has steadily increased compared to the previous year, while the proportion of studies investigating innovative medicines whose inclusion criteria include pregnant women , decreases (Figure 1). This indicates that this issue is a global issue affecting women outside of Australia and that a global call to action may be warranted to ensure pregnant women are not excluded from potentially life-saving treatments.