Nasty side effect of new birth control pill: 'Too many women got pregnant in the Netherlands'

©Volodymyr Hryshchenko

A new pill seemed promising because it provided fewer side effects, but apparently did not do what it promised to do. Indeed, too many women turned out to have fallen pregnant anyway.

Specifically, the study involved a hormone-free birth control pill based on the substance mifepristone. The research was conducted at Leiden University Medical Center (LUMC), but had to be stopped in early June because too many women fell pregnant anyway. After all, the interim evaluation showed that mifepristone 50mg is not suitable as a contraceptive.

Some of them even experienced ectopic pregnancies. This obviously worried the researchers. More than 500 women and fourteen Dutch hospitals participated in the study that started in 2025. Every week they took a pill of mifepristone. But after interim evaluation, the contraceptive was found to be "not effective and safe enough".

The drug initially seemed well suited for women who are not allowed to use hormones or for women who suffered side effects from contraception containing estrogens and/or progestogens. The mifepristone-based pill caused fewer side effects, several women indicated in the study. But too many participants in the study became pregnant anyway. Consequently, Leiden University Medical Center (LUMC) decided to stop the research on the new birth control pill. Research into mifepristone will continue, but no longer as a contraceptive pill. After all, the substance could still be of interest in other situations.

©Volodymyr Hryshchenko - illustration image