Dutch study of new contraceptive halted after many pregnancies, several ectopic cases

A clinical study into a new contraceptive pill has been stopped early after an unexpectedly high number of participants became pregnant. Leiden University Medical Center (LUMC) said the decision was mainly driven by concerns over ectopic pregnancies observed during the trial.

Mifepristone (50 mg) was being developed as a potential breakthrough contraceptive, with expectations that it would cause fewer side effects than the conventional pill. At a higher dose of 200 mg, mifepristone has already been widely used for many years to induce abortions and to manage miscarriages.

“This is very disappointing,” says lead researcher Rebecca Gomperts of LUMC. “Because this drug seemed particularly suitable for women who are not allowed to use hormones or women who experienced side effects from contraception containing oestrogens and/or progestogens.”

The study involved 14 hospitals across the Netherlands and more than 500 female participants. All participants have been notified that the WOMEN&More study has been discontinued.

In the study, which began last year, participants were required to take one tablet per week. The exact number of pregnancies and ectopic pregnancies among the participants will only be disclosed later in a scientific publication.

Gomperts emphasised that any figures must be presented in a proper context, but said the numbers involved were not high. The findings nonetheless indicate that mifepristone is “not effective and not safe enough” as a contraceptive method.

Gomperts would like further research into mifepristone, because she believes the drug is suitable for other purposes. “It works very well as a morning-after pill,” the doctor says. It also helps with menstrual complaints. “For those for whom it worked, it was a solution,” Gomperts said about the study. She adds that some participants experienced far fewer side effects than with other forms of contraception.

The doctor said it took a decade to get the study off the ground, with securing funding proving especially difficult. She added that earlier research on mifepristone had been shorter in scope, meaning these longer-term results could only now be properly assessed for the first time.

The LUMC states that mifepristone at a 200 mg dosage, used for medical abortion and miscarriage treatment, continues to be regarded as highly safe and effective.