Why Some People Have Repeating Miscarriages

Many women know the pain of suffering through pregnancies that don't make it to term, but what they might not know is that research is suggesting repeating miscarriages are linked to a lack of stem cells. A new study released by the University of Warwick (UoW) in the UK, along with University Hospitals Coventry and Warwickshire NHS Trust, have found that there is a link between recurrent miscarriages (three or more) and a lack of stem cells in the uterine lining. Miscarriage is considered the most common type of pregnancy loss, with up to 25 percent of all known first-trimester pregnancies end in miscarriage — and that's without considering the pregnancies that are lost without women even knowing about them in the first place.

It's understandable why women around the world have been aching for an answer other than "it just happens" (which is hardly comforting in the midst of such a profound loss). But researchers have struggled to pinpoint one answer — theorizing everything from disease to chromosomal abnormalities in the embryos. However, this new research, published in the journal Stem Cells, may not only provide the peace of mind these women need, but also answers that could potentially save babies' lives.

Co-author of the study Jan Brosens, a professor of obstetrics and gynecology at UoW who has been studying miscarriage for years, told mental_floss that prior to now, there has been no clear reason for pregnancy loss. “For decades we have been screening for clotting abnormalities and immune disorders, and so on. We started to realize that in the vast majority of women you can test until you are blue in the face and you will find nothing.” However, they were able to distinguish that women with obesity are more likely to have a lower number of stem cells.

To determine this, they examined the uterine tissue of 183 women being treated at the hospital's Implantation Research Clinic. “We were looking for methylation changes,” Brosens said. They discovered significant epigenetic signatures, which means that the epigenetic mechanisms (which are used by cells to control gene expression) weren't functioning normally. What this means is that there is a lack of stem cells (where the epigenetic signatures are) and it was common in the patients with recurrent miscarriages.

To put it simply, stem cells are what make the endometrium (uterine lining) sensitive to the chemical signals of an embryo. Without this "communication," the cells aren't able to interpret the signals as to whether or not the embryo is viable or not, and so the lining is discarded with the next menstrual cycle.

In terms of treatment, there are a few options: we have to either learn to control and maintain the stem cell population in the endometrium, be able to detect predictive signatures in the endometrium that can help assess a woman’s risk of miscarriage, or develop therapies to increase the stem cell supply. Either way, the sheer fact that we have a better idea of what's going on with our bodies is never a bad thing. May this be the beginning of healthier, happier, more informed mothers-to-be.

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