Women's health

Many miscarriages may have
a common cause

Low serum concentrations of a protein in the placenta could
be the trigger

By Marcello Palmieri

After giving birth to her first child, France Veronneau, a finance officer from Montreal, suffered two consecutive miscarriages and was told by her doctor that she probably wouldn't conceive again. With this prognosis, she and her husband decided to adopt.

Suffering a miscarriage is a devastating experience for any woman. Compounding the problem, it's often very difficult to pinpoint the cause of miscarriage, as was the case with France. A group of researchers from Australia believe that they may have found the key to one cause of miscarriage: low serum concentrations of a protein called macrophage inhibitory cytokine 1 (MIC 1). It occurs naturally in the womb and appears to increase during pregnancy. It's believed to have immunomodulatory actions that can help a fetus stay alive. The recent study hypothesized that when MIC 1 levels are low, miscarriage can occur.

It's estimated that about 10-15 % of all pregnancies end in miscarriage and approximately 1-2 % of women experience at least three miscarriages, known as recurrent miscarriage. Early miscarriage, prior to 12 weeks, is believed to result from genetic abnormalities while late miscarriage, occurring between 13-20 weeks, may result from anatomical problems. Mrs Veronneau suffered both miscarriages 11 weeks into her pregnancy but never got a clear answer as to why this happened. "It's only three months, but it's still a big loss when you lose your baby," she said.

In the Australian study, published in the January 10 issue of The Lancet, Dr Stephen Tong and colleagues measured serum concentrations of MIC 1 taken at six to 13 weeks of pregnancy. Of the 300 women who participated in the study, 100 miscarried while 200 carried to term. The MIC 1 serum concentrations were a third lower in the women who suffered miscarriages, compared to levels in the 200 women who carried to term. Researchers also noted that these low concentrations were detected three weeks before the miscarriages occurred. "Changed production of MIC 1 in the placenta is part of the mechanism initiating spontaneous pregnancy loss," stated the study. The authors also pointed out that if a link does exist between low MIC 1 concentrations and miscarriage, then an understanding of the role MIC 1 plays during pregnancy may lead to innovative therapies for the prevention of miscarriage. The Australian researchers also stated that more research is needed to confirm their findings.

In an accompanying commentary, Dr Galit Sarig and Dr Benjamin Brenner, two specialists from Rambam Medical Centre, Haifa, wrote that we need to determine whether low levels of MIC 1 cause miscarriage or if they occur simultaneously with miscarriage. "If the results can be confirmed, the way is open to develop novel therapies to prevent pregnancy loss," they wrote. This is certainly good news for the thousands of women who've suffered through miscarriage.

At least Mrs Veronneau's story has a happy ending. As often seems to happen, shortly after she adopted her baby, she discovered that the "impossible" had happened: she was pregnant. She met with doctors once a month to monitor her progress and gave birth to a healthy baby boy.