Progesterone treatment to help prevent miscarriage signals hope for some women

Posted: 17/07/2019

Many would-be parents tragically suffer the heart-breaking experience of a miscarriage. Up to one in four recognised pregnancies end in miscarriage, with 85% of these happening in the first trimester (12 weeks) of pregnancy.

While miscarriage is a one-off event for many women who go on to have successful pregnancies, it can occur multiple times for others. For these women, the findings of a trial undertaken at Tommy’s National Centre for Miscarriage Research signal hope.

Progesterone is a hormone which is naturally produced in the body and causes the womb lining to thicken, helping an embryo embed into the mother’s womb. The results of the trial, recently published in the New England Journal of Medicine, indicates that giving progesterone to pregnant women with early bleeding and a history of multiple miscarriages could increase the chances of the baby’s survival. The more miscarriages the mother had previously suffered, the greater the benefit of the progesterone.

It is common to have light bleeding without pain within the first trimester of pregnancy. Possible causes include implantation bleeding when the fertilised egg embeds itself into the wall of the womb; hormonal changes to the cervix or, occasionally, infection. Bleeding during the first trimester is often not a cause for concern but, if it occurs after 12 weeks, the advice is to seek immediate medical attention as it could be a sign of miscarriage.

Although previous studies have been carried out into the potential benefits of progesterone to prevent miscarriage, these had much smaller control groups thus yielding less reliable results. The trial conducted at Tommy’s National Centre for Miscarriage Research involved 4,153 pregnant women presenting with early bleeding.

Half of the women participating in the trial were given a placebo and the other half were given progesterone. The trial was randomised (the participants given progesterone were selected at random by a computer) and double blind (they were not told whether they would be taking progesterone or a placebo). The women in the trial had to take progesterone vaginally as a pessary twice a day.

While the results did not demonstrate that progesterone helped all women with early bleeding to prevent miscarriage, when the participants were grouped by the number of previous miscarriages they had suffered, they revealed the following:

• There was no statistically significant benefit for women without a previous history of miscarriage – 26% of participants given progesterone went on to miscarry, compared to 25% given a placebo
• For participants with a history of one or two previous miscarriages, progesterone showed some benefit – 24% of participants given progesterone suffered miscarriage, compared to 28% given a placebo
• For those participants with a history of three or more miscarriages, progesterone was shown to have a substantial benefit – 28% of participants in the progesterone group suffered miscarriage compared to 43% in the placebo group.

Given the statistically significant benefit that progesterone was shown to have for mothers with a history of multiple (three or more) miscarriages, the recommendation following the trial is for women falling within this group to ask for progesterone from their doctor if they experience early bleeding in pregnancy.

Rosie Nelson, associate in the clinical negligence team at Penningtons Manches Cooper, commented: “Miscarriage is very sadly such a common occurrence and, in the majority of cases, there is nothing the mother could have done to prevent it. This of course does not make it any less painful to know when it happens to you. The results of this trial are very heartening for would-be parents who have repeatedly endured the heart-break of miscarriage.

“It is thought that most miscarriages are caused by abnormal chromosomes which prevent the normal development of the foetus. However, in a small percentage of cases, miscarriage can be brought about as a result of negligent care of the mother during pregnancy. If you have reason to believe that you have suffered an avoidable miscarriage as a result of treatment you have received, our team of experienced solicitors can help.”

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