Women with a history of miscarriages are six times more likely to have a baby if they take a natural hormone treatment before trying to conceive, a new study shows.
Progesterone – which can be taken as an injection, gel, or tablet – been used for years to treat infertility.
But until now, few studies have seriously examined it as a candidate to beat miscarriage.
The new research shows that endometrial glands (the inner lining of the uterus) may play a larger role in early pregnancy than previously thought.
The study was published in Fertility and Sterility, the international journal of the American Society for Reproductive Medicine.
By stabilizing the endometrium, progesterone could eliminate some of the major risk factors that mean one in 20 women lose a baby in the first trimester.
And a genetic test could identify which women would benefit from having progesterone, which plays a role in maintaining pregnancy.
Miscarriages are the loss of a pregnancy during the first 23 weeks and are more common than thought.
Recurrent miscarriages where the woman loses three or more pregnancies in a row are far less common, affecting around one in 100 women.
It is thought that most miscarriages are caused by abnormal chromosomes in the baby – genetic ‘building blocks’ that guide the development of a baby. If a baby has too many or not enough chromosomes, it won’t develop properly.
Prof. Mary Stephenson at the University of Illinois, United States, said: “Recurrent pregnancy loss is a heartbreaking challenge for as many as one in 20 women although it is not often openly discussed.
“And while we know a lot about sporadic miscarriage, which is a natural mechanism of the body when there is a chromosome error at conception, we do not know nearly enough about unexplained recurrent pregnancy loss.”
Unlike previous studies, the new study of progesterone supplementation looked at a large and specific group of 116 women with a history of recurrent pregnancy loss.
Dr. Stephenson worked with Dr. Harvey Kliman at the Yale University School of Medicine, who specialises in the endometrium – the inner layer of the uterus. They identified women with abnormal endometrial development by examining the expression of nuclear cyclin E, or nCyclinE.
Women with abnormal levels of nCyclinE, a molecular marker for the health of the endometrium, were prescribed progesterone during the second half of their menstrual cycle, when the uterine lining matures in preparation for a possible pregnancy.
The scientists found two-thirds of pregnancies successful in women who received progesterone in the form of a vaginal gel, compared to barely half in women who did not receive the hormone.
Stephenson said: “We are very pleased to find that these results reinforce the evidence that progesterone could be a very beneficial, inexpensive and safe treatment for many women with a history of recurrent pregnancy loss..”
She added the results also indicate that molecular markers like nCyclinE could help doctors determine which patients would benefit from progesterone, and at what dose.
Kliman who invented the Endometrial Function Test (ENF) to measure CyclinE levels and identify women with infertility said: “This study has shown that the EFT can also be an important tool for patients with recurrent pregnancy loss.”
Meanwhile, miscarriage, also known as spontaneous abortion and pregnancy loss, is the natural death of an embryo or fetus before it is able to survive independently. Some use the cutoff of 20 weeks of gestation after which fetal death is known as a stillbirth.