Hope for many couples as progesterone shown to reduce risk of miscarriage in some women

New research has shown that progesterone could increase live births in women with early pregnancy bleeding and a history of miscarriage


Research carried out in the Tommy’s National Centre for Miscarriage Research suggests that giving progesterone to pregnant women with early pregnancy bleeding and a history of miscarriage could increase their chances of having a baby.

The PRISM trial, funded by the National Institute for Health Research (NIHR) and co-ordinated in the University of Birmingham in collaboration with Tommy’s National Centre for Miscarriage Research, is the largest ever trial of its kind and involved 4,153 pregnant women who presented with early pregnancy bleeding.

The women, being treated at 48 hospitals across the UK and with the average age of 31, were randomly assigned by computer into one of two groups – one group of 2,079 women were given progesterone, while the other group of 2,074 women were given a placebo.

PRISM image

Dr Adam Devall, Senior Clinical Trial Fellow at the University of Birmingham and Manager of Tommy’s National Centre for Miscarriage Research, explained: “Miscarriage is a common complication of pregnancy, affecting 1 in 5 women, and vaginal bleeding in early pregnancy is associated with a 1 in 3 risk of miscarriage.

“Several small studies have suggested that administering progesterone, a hormone essential for maintaining a pregnancy, may reduce the risk of miscarriage in women presenting with early pregnancy bleeding.

“The PRISM trial was undertaken to answer a very important research question; whether progesterone given to pregnant women with threatened miscarriage would increase the number of babies born after at least 34 weeks of gestation when compared with a placebo.”

Benefit applies to those with previous history of miscarriage

While the research did not show statistically strong enough evidence to suggest that progesterone could help all women who are suffering early pregnancy bleeding to go on to have a baby, importantly the results did show the hormone benefited those who had early pregnancy bleeding and had previously suffered a miscarriage.

What did the results show?

The results showed that although the treatment did not reduce the rate of miscarriage for those with no previous miscarriages, there was a small reduction in miscarriage for those with 1-2 previous miscarriages and a big reduction in miscarriage for those with 3 or more previous miscarriages.

The overall live birth rate was 75% (1513/2025) in the progesterone group and 72% (1459/2013) in the placebo group. That 3% difference in live birth was not ‘statistically significant’ – meaning that the difference could have been due to chance.

However, when the results were split by the number of previous miscarriages that the participants had suffered, the analysis showed that:

  • No previous miscarriages: the live birth rate was 74% (824/1111) in the progesterone group and 75% (840/1127) in the placebo group, ie no benefit
  • 1-2 previous miscarriages: the live birth rate was 76% (591/777) in the progesterone group and 72% (534/738) in the placebo group, ie some benefit
  • 3 or more previous miscarriages: the live birth rate was 72% (98/137) in the progesterone group and 57% (85/148) in the placebo group, ie substantial benefit

The ground-breaking research was published today in the New England Journal of Medicine.

The role of progesterone uncertain for years

Arri Coomarasamy, Professor of Gynaecology at the University of Birmingham and Director of Tommy’s National Centre for Miscarriage Research, said: “The role of progesterone in women with early pregnancy bleeding has been studied and debated for about 60 years, however what we have previously lacked is high quality evidence.

“The largest study before the PRISM trial had less than 200 participants; whereas our study had more than 4,000 participants and was of very high quality, which means we can be confident in our findings.

“Our finding that women who are at risk of a miscarriage because of current pregnancy bleeding and a history of a previous miscarriage could benefit from progesterone treatment has huge implications for practice. This treatment could save thousands of babies who may have otherwise been lost to a miscarriage.

“We hope that this evidence will be considered by the National Institute for Health and Care Excellence (NICE) and that it will be used to update national guidelines for women at risk of miscarriage.”

Jane Brewin, Chief Executive of Tommy’s, said: “The results from this study are important for parents who have experienced miscarriage; they now have a robust and effective treatment option which will save many lives and prevent much heartache.

“It gives us confidence to believe that further research will yield more treatments and ultimately make many more miscarriages preventable.”

I have early pregnancy bleeding. Where can I get this treatment?

If you have early pregnancy bleeding and have suffered one or more previous miscarriages you should request progesterone treatment. As many clinicians will not have heard of this very recent research we have developed a simple and clear infographic that you can bring with you to the doctor that clearly explains the benefits of the treatment.

Find out more about bleeding in pregnancy

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Please note that these comments are monitored but not answered by Tommy’s. Please call your GP or maternity unit if you have concerns about your health or your baby’s health.
  • By Zain (not verified) on 16 Jul 2019 - 20:53

    Hello, I have suffered 3 miscarriages and I was wondering if progesterone is available on South Africa and can my doctor prescribe it.

  • By Katie (not verified) on 7 Jul 2019 - 16:00

    What does the progesterone trial mean for women who have had missed miscarriages with no vaginal bleeding? Does this mean women should take progesterone at the start of pregnancy to prevent miscarriage? Can anyone give any advice?
    Thanks Katie

  • By alex (not verified) on 23 May 2019 - 16:13

    don't know if im pregnant?

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