New research from the University of Birmingham has shown that progesterone supplements in the first trimester of pregnancy do not improve outcomes in women with a history of unexplained recurrent miscarriages.

The findings, published in The New England Journal of Medicine, mark the end of a five year trial and provide a definitive answer to 60 years of uncertainty on the use of progesterone treatment for women with unexplained recurrent losses.

Recurrent miscarriage

The study of 826 women with previously unexplained recurrent miscarriage showed that those who received progesterone treatment in early pregnancy were no less likely to miscarry than those who received a placebo. This was true whatever their age, ethnicity, medical history and pregnancy history.

Though the results of the PROMISE (progesterone in miscarriage treatment) trial will be disappointing to many, it will allow researchers to direct their efforts towards exploring other treatments that can reduce the risk.

Positives

Professor Arri Coomarasamy says: “We had hoped, like many people, that this research would confirm progesterone as an effective treatment. Though disappointing, it does address a question that has remained unanswered since progesterone was first proposed as a treatment back in 1953. Fortunately, there are a number of other positives that we can take from the trial as a whole.”

The trial results also showed that there were no significant negative effects of progesterone treatment for women or for their babies. This is important information for women taking progesterone for other reasons, such as fertility treatment, or for those taking part in other trials.