Pregnant women who experienced several miscarriages in the past are sometimes prescribed to take progesterone supplement to avoid another miscarriage.

Low levels of progesterone cause some women to experience miscarriage, also known as "spontaneous abortion," which is why progesterone supplementation was believed to increase the likelihood for live births and newborn survival particularly in expectant mothers who have had unexplained miscarriages in the past.

Findings of a new study, however, revealed that giving the hormone supplement during the first trimester of pregnancy does not increase the chances for live birth or boost odds for newborn survival.

In a new study published in the New England Journal of Medicine on Nov. 26, Arri Coomarasamy, from the University of Birmingham in the UK, and colleagues involved more than 800 women between 18 and 39 years old who previously experienced unexplained and recurrent miscarriages and who used a daily vaginal supplement of either 400 milligrams progesterone or placebo until the 12th week of their pregnancy.

In women given progesterone, 65.8 percent successfully gave birth to a baby. Pregnancy success rate in those given the placebo, on the other hand, was 63.3 percent showing that there was not a significant difference between women in both groups in their odds for successful pregnancy.

"Our trial showed no significant increase in the rate of live births with the use of vaginal progesterone in the first trimester of pregnancy among women with recurrent miscarriages," the researchers wrote in their study. "Our results do not support the earlier findings of a Cochrane review that suggested a benefit of progesterone therapy in the first trimester among women with recurrent miscarriages."

Although the results of the study may appear disappointing, the researchers said that these would allow researchers to focus their efforts on looking for other treatments that prove effective in reducing miscarriage risks.

"Though disappointing, it does address a question that has remained unanswered since progesterone was first proposed as a treatment back in 1953," Coomarasamy said. "Fortunately, there are a number of other positives that we can take from the trial as a whole."

The results likewise showed no link between using supplemental progesterone and increased risks for congenital abnormalities. Supplementation did not also appear to have negative effects on women.

This information is crucial particularly for women who take progesterone for other reasons including those who participate in other trials and those who use it for fertility treatment,