You May Be Expecting a Preemie

Progesterone to prevent preterm birth not effective for women with short cervixes

/ Author:  / Reviewed by: Chris Galloway, M.D.

(RxWiki News) There are a variety of risk factors for giving birth early. Preemies are at risk for different health problems. So, identifying which women are at risk for having preemies is important for both mom and child.

But equally important is knowing what to do for a woman who may be likely to give birth early.

Some doctors suggest taking progesterone during pregnancy to help prevent "preterm birth" for women already known to be at risk for it.

However, a recent study found this preventive option does not work for all women at risk of giving birth early.

"Attend all prenatal appointments."

The study, led by William A. Grobman, MD, of Northwestern University in Chicago, aimed to find out whether giving progesterone to women with short cervixes might reduce their risk of having a preemie.

Having a short cervix during the second trimester is known to increase a woman's risk of having a preemie.

The cervix is the bottom tunnel part of the uterus that a baby travels through during birth. It naturally shortens as a woman gets closer to giving birth.

Past research has already shown that giving women the hormone progesterone can be effective in reducing the risk of having a baby early if the woman has already had one preemie.

Therefore, last year, the U.S. Food and Drug Administration approved the synthetic version of progesterone called 17 alpha-hydroxyprogesterone caproate (17-OHP) for women who have already had one preterm birth to potentially prevent another.

For this study, 657 women with cervixes less than 30mm during the second trimester were randomly split into two groups. All the women were pregnant with their first child.

One group of women (327) received an injection of 17-OHP once a week through their 36th week of pregnancy. The other women (330) received a placebo injection (no medication).

The researchers calculated how many women in both groups gave birth before the 37th week of pregnancy.

They found 25.1 percent of the women receiving 17-OHP gave birth early, and 24.2 percent of the women getting the placebo gave birth early. There was also little difference in the rates of complications for the babies after birth.

Therefore the researchers concluded  the injections of 17-OHP did not help prevent preterm birth for women with a short cervix.

The study was published September 17 in the American Journal of Obstetrics and Gynecology. The research was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The authors reported no conflicts of interest.

Reviewed by: 
Review Date: 
October 22, 2012
Last Updated:
October 25, 2012