 "Progesterone may not help women with miscarriage history")
Giving progesterone to women who have had three or more miscarriages does not improve their chances of carrying a pregnancy to term, according to a recent study.
Researchers had hoped that pregnant women who were given supplemental progesterone early in their first trimester would be less likely to miscarry than women who did not have it. Previous studies suggested progesterone could lower the risk among women with a history of recurrent miscarriages.
But the results of the new trial, published in The New England Journal of Medicine, show that 66 per cent of the women given progesterone gave birth to a baby, compared with 63 per cent of the control group - not a significant difference.
Over 800 women participated in the trial at 36 sites in Britain and nine in the Netherlands. Neither they nor their doctors knew whether they were receiving progesterone or a placebo, provided via vaginal suppositories.
"It's an awfully good study, and the first well-designed study on this topic," said Samantha M Pfeifer, chairwoman of the practice committee for the American Society for Reproductive Medicine, who was not involved in the new research.
"There's always disappointment whenever you find out that a magic bullet isn't a magic bullet," she added.
About five per cent of women experience two consecutive miscarriages in the first trimester, and one per cent go through three or more losses. Progesterone, a hormone that is crucial to bringing about and maintaining pregnancy, is often a first-line treatment for unexplained recurrent miscarriages.
The negative result is sure to dismay patients, but it comes with a silver lining, experts said. Couples should take solace in the "impressive" result that "more than half of these women had a live birth," Pfeifer said. The study also suggested that supplemental progesterone did not lead to an increase in congenital abnormalities. "Progesterone doesn't cause harm," said Arri Coomarasamy, the trial's lead author and a professor of gynaecology at the University of Birmingham.
Some experts wondered if progesterone should have been given to the study subjects earlier - perhaps after ovulation, and not only after confirmation of the pregnancy.
"My big concern is they are starting the progesterone too late," said Mary D Stephenson, chief of obstetrics and gynaecology at the University of Illinois at Chicago, who was not involved in the new research. "You have to start it before they are pregnant."
Miscarriage is often caused by chromosomal errors that happen by chance. This kind of genetic fluke becomes more likely as a woman ages, which is why enrollment age in the study was capped at 39.
Some specialists suggested the study should have included only women with at least one miscarriage clearly unrelated to chromosomal errors.
"No amount of progesterone or any medication can fix a situation where the fetus doesn't have the right number of chromosomes," said Zev Williams, the director of the program for early and recurrent pregnancy loss at Albert Einstein College of Medicine and Montefiore Medical Center in the Bronx.
"It would be quite a different study if they recruited patients with miscarriages that had normal chromosomal results," Stephenson said. "If progesterone was effective, we'd be much more likely to see a difference."
Pfeifer disagreed, saying, "It would have been nice to have that information, but I'm not so sure that it is a make-or-break deal." The study did exclude women with known causes of miscarriage, like structural problems with the uterus, clotting disorders or thyroid dysfunction.
©2015 The New York Times News Service
