12:46pm

Thu April 7, 2011
Shots - Health Blog

A Hormone Gel Helps Prevent Premature Births

For pregnant women who get diagnosed with a short cervix, an ordinary pregnancy can become an exercise in anxiety about a baby that might arrive too soon.

The condition increases the chances of delivering a premature baby by 50 percent or more.

But a recent study by the National Institutes of Health shows the hormone progesterone, applied vaginally as a gel, reduces the rate of premature delivery in high-risk women in the middle trimester of pregnancy. The hormone reduced the rate of preterm deliveries before 33 weeks by 45 percent, and improved the health of the babies.

One such mother, Kai Paul, now has a healthy 1-year-old , but he didn't come easy after she was diagnosed with short cervix.

To reduce Paul's chances of delivering early, doctors put her on strict bed rest, but she was told there was little else they could do.

Until recently, that was true. In the United States, about half a million women give birth prematurely each year. Premature birth is the leading cause of infant mortality, and up to now, there's been little to do about it.

As Roberto Romero, one of the study's authors, explains, during pregnancy, progesterone keeps a woman's cervix long and closed, and her uterine muscles quiet. Before delivery, the cervix shortens and opens and the uterine muscles begin to contract. But some women have a progesterone deficiency that causes that to happen too soon.

One of every two women with a cervix of less than 15 millimeters will deliver a preterm baby. "A short cervix is the most powerful predictor of preterm delivery that we currently have in medicine," says Romero.

Paul, who was diagnosed with a cervix of 11 millimeters, was fortunate. She was enrolled in the study, and was one of the women who received the progesterone treatment instead of placebo –- giving her and her son a better chance at success. In addition to the bed rest, she applied the gel every night herself with a tampon-like applicator throughout her pregnancy.

It worked. Her pregnancy was successfully extended to term and the baby was born without a hitch.

Romero says success stories like Paul's represent a huge leap forward. "I believe this is a 'game-changer,' " says Romero. "One, we have a way to screen, and second we have a way to intervene before the patient develops premature labor."

Romero estimates that the treatment may reduce the rate the rate of preterm deliveries worldwide by a quarter of a million every year.

The Food and Drug Administration recently approved a drug, given as a weekly injection, that experts say could also make a dent in premature births in women who've had them before.

The drug, marketed as Makena, isn't a magic bullet, though. Research showed that 37 percent of women who got weekly injections of it delivered prematurely, compared to 55 percent of women who got injections of a placebo. And its high price has sparked controversy. Under pressure, the manufacturer reduced the price to a still-steep $690 per shot from the original $1,500.

As for the NIH results, doctors say they raise the question of whether all pregnant women should be screened for a short cervix, and whether the progesterone treatment can be useful in reducing the risks for women with a longer cervix as well. Currently, women aren't routinely screened for cervical length, and many do not have a history of preterm birth that would point to a possible risk. Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.

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