A woman’s bone marrow may determine her ability to have a baby, suggests a new study.
Researchers found that when an egg is fertilised, stem cells leave the bone marrow and travel via the bloodstream to the uterus, where they help transform the uterine lining for implantation.
If the lining fails to go through this essential transformation, the embryo cannot implant, and the body terminates the pregnancy.
Study senior author Professor Hugh Taylor, of Yale University in the United States, said: “We have always known that two kind of things were necessary for pregnancy.
“You must have ovaries to make eggs, and you must also have a uterus to receive the embryo.
“But knowing that bone marrow has a significant role is a paradigm shift.”
Until now it wasn’t known how stem cells affected a pregnant uterus.
Bu the new study proves the physiological relevance of stem cells to pregnancy.
Study first author Dr. Reshef Tal, Assistant Professor of obstetrics, gynecology and reproductive sciences at Yale, said: “Some of these bone marrow-derived mesenchymal stem cells travel to the uterus and become decidual cells, which are the cells that are essential for the process of implantation and pregnancy maintenance.”
Using mice, researchers found that a bone marrow transplant from a healthy donor could improve fertility.
This study was made possible by a methods breakthrough that Dr Tal and Prof Taylor made a few years ago.
For more than two decades, Prof Taylor and his team had been trying to restore fertility in mice with genetic mutations, but until recently, they didn’t have a form of chemotherapy strong enough to allow an effective bone marrow transplant without killing all the eggs of the mice.
Dr Tal said: “We used an anti-metabolite drug, which is still considered a chemotherapy, but it doesn’t harm the ovary, and therefore the mice are still able to get pregnant, allowing us to track the transplanted bone marrow cells and investigate their role in reproduction.
“We are currently translating these findings into humans to better understand the role that these bone marrow-derived stem cells play in recurrent implantation failure and recurrent pregnancy loss, two conditions that are unexplained in the majority of women and have no effective treatment.”
Though more research is needed prior to clinical trials, the research team see hope for the patients they treat for infertility on the clinical side of their practice.
Prof Taylor said: “These are frustrating medical conditions.
“When you have a damaged endometrium leading to infertility or repeated pregnancy loss, all too frequently we have not been able to correct it.
“Bone marrow can be considered another critical reproductive organ.”
He added: “We are currently translating these findings into humans to better understand the role that these cells play in recurrent implantation failure and recurrent pregnancy loss, two conditions that are unexplained in the majority of cases and have no effective treatment.
“The findings of this study open exciting new avenues for research into the cause of these conditions as well as developing new treatments for women suffering from them.
“This finding opens up a new potential avenue for treatment of a condition that has been untreatable in the past.”
The findings were published in the journal PLOS Biology.