Progesterone therapy may prevent miscarriages in some women

By Nicole MacKee
Progesterone therapy may help to prevent miscarriage in women with early­-pregnancy bleeding and a history of previous miscarriage, according to researchers who say the treatment could save the lives of thousands of babies each year.

An analysis of the PROMISE (PROgesterone in recurrent MIScarriagE) and PRISM (Progesterone In Spontaneous Miscarriage) trials, published in the American Journal of Obstetrics and Gynaecology, found that treating women with early bleeding with twice­-daily vaginal micronised progesterone (400 mg) was associated with an increasing number of live births in line with the number of previous miscarriages.

For women with current bleeding and a history of one previous miscarriage, there was a 5% risk difference of achieving a live birth between the progesterone group (75%) and the placebo group (70%). This increased to a 15% risk difference among women who had had three or more previous miscarriages (72% vs 57%). No short-term safety concerns were found.

The researchers estimated that this treatment strategy would result in 8450 more live births in the UK each year.

Dr Elizabeth McCarthy, a maternal­-fetal medicine specialist and obstetrician at Mercy Hospital for Women and the Northern Hospital, in Melbourne, and a senior lecturer at the University of Melbourne, said if the researchers’ estimates were accurate, this would equate to 2800 saved lives in Australia. However, she said, such a therapeutic approach would represent a significant shift in practice.

‘Progesterone is not used at all really in standard emergency department or GP presentations in women who have a small amount of bleeding in early pregnancy,’ Dr McCarthy said.

Up to 50% of women experienced bleeding in early pregnancy, she said, and many of these women would go on to have a live birth on ‘fresh air’.

‘Even women who have had five or six previous miscarriages, may have as good as a 50/50 chance of a live birth with the next pregnancy,’ she said.

Dr McCarthy said the prospect of babies’ lives being saved was extremely emotive, so practice change was likely to be driven by women requesting progesterone, which was not listed on the PBS for this indication.

She said patients needed to understand that uncertainties about the therapy remained; there could be side effects, such as bloating and constipation; and it may not be appropriate for women aged over 39 years.

A health economic analysis of PRISM data, published in BJOJ: an International Journal of Obstetrics and Gynaecology, found that progesterone treatment was cost-effective. Dr Ilias Goranitis, coauthor and Senior Research Fellow in Health Economics at the University Melbourne, said the analysis concluded that progesterone treatment was cost effective not only to those women with history of miscarriage but to all women presenting with early pregnancy bleeding. He confirmed that the findings were generalisable to Australia.
Am J Obstet Gynecol 2020;
BJOG 2020;