Progesterone may prevent multiple miscarriages, says new study

For decades, doctors have prescribed progesterone, one of the key hormones your body needs during pregnancy, to prevent a miscarriage. The hormone, produced by the ovaries, is necessary to prepare the body for implantation. As the pregnancy progresses, the placenta produces progesterone, which suppresses uterine contractions and early labor.

But a new study out of the UK finds that administering progesterone to women experiencing bleeding in their first trimester does not result in dramatically more successful births than a placebo. Yet, for a small group of mothers-to-be who had experienced “previous recurrent miscarriages,” the numbers showed promise.

The study, conducted at Tommy’s National Centre for Miscarriage Research at the University of Birmingham in the UK, is the largest of its kind, involving 4,153 pregnant women who were experiencing bleeding in those risky (and nerve-wracking) early weeks. The women were randomly split into two groups, with one group receiving 400 milligrams of progesterone via a vaginal suppository, and the other receiving a placebo of the same amount. Both groups were given the suppositories through their 16th week of pregnancy.

Of the group given progesterone, 75% went on to have a successful, full-term birth, compared to 72% for the placebo.

As the study notes, for most women, the administration of progesterone “did not result in a significantly higher incidence of live births than placebo.” But for women who had experienced one or two previous miscarriages, the result was a 4% increase in the number of successful births. And for women who had experienced three or more recurrent miscarriages, the number jumped to a 15% increase.

Dr. Arri Coomarasamy, Professor of Gynecology at the University of Birmingham and Director of Tommy’s National Centre for Miscarriage Research, said the implications for that group are “huge.” “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,” he said.

It’s estimated that 1 in 5 pregnancies ends in miscarriage. And while even a spot of blood no doubt increases the fear in every expectant mother’s mind, bleeding is actually a very common occurrence during pregnancy, Coomarasamy said. Still, first trimester bleeding is particularly risky, with a third of women who experience it going on to miscarry.

So for women who have been through it multiple times, Coomarasamy’s findings are an important avenue to explore. “This treatment could save thousands of babies who may have otherwise been lost to a miscarriage,” he added.

The study is among a number of recent groundbreaking discoveries made by doctors looking to further understand what causes miscarriages and what can be done to prevent them. While about 70% of miscarriages are attributed to chromosomal abnormalities, doctors recently learned that certain genetic abnormalities, which exist in a small group of parents-to-be, could be discovered by testing the mother and father, as well as the embryo.

Doctors have also discovered that even knowing the sex of your baby could predict the complications a mother may face, thus helping medical professionals to assist in keeping the pregnancy viable.

But while there is no sweeping solution to stop miscarriages, for some couples, the use of progesterone does offer a glimmer of hope. “The results from this study are important for parents who have experienced miscarriage,” Jane Brewin, chief executive of Tommy’s said. “They now have a robust and effective treatment option which will save many lives and prevent much heartache.”

Brewin added that studies like this one are imperative to our understanding of how the creation of life, which remains both a miracle and a mystery, truly works. “It gives us confidence to believe that further research will yield more treatments and ultimately make many more miscarriages preventable,” she said.

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