FRIDAY, Feb. 4 (HealthDay News) -- The U.S. Food and Drug Administration has approved the first drug to help prevent premature birth in women who have had at least one previous preterm delivery.

The drug -- called Makena (hydroxyprogesterone caproate) -- is expected to reduce the risk of premature delivery, which experts say raises the risk of infant complications at birth, lifelong disabilities such as cerebral palsy, and even death.

Preterm delivery is a serious problem in the United States, FDA spokeswoman Shelly Burgess said.

According to the March of Dimes, preterm birth -- or the birth of a baby at less than 37 completed weeks of pregnancy -- affects one in eight babies born in the United States, she noted.

What's more, the rate of preterm birth has increased more than 35 percent in the last 25 years in the United States, and late preterm births -- babies born at 34 to 36 weeks of pregnancy -- account for nearly three-quarters of such births, Burgess said.

Makena will reduce the risk of preterm delivery before 37 weeks of gestation in pregnant women with a history of at least one spontaneous preterm birth, Burgess noted.

She added that Makena is approved for a certain subset of all U.S. women at risk for preterm birth: those carrying one baby (known as a "singleton pregnancy") who previously gave birth prematurely to one baby.

According to the agency, the drug is not intended to be used by women having twins or other risk factors for preterm birth.

The March of Dimes applauded the FDA's decision.

"The most common risk factor for preterm birth is recurrence," said Dr. Alan Fleischman, March of Dimes senior vice president and medical director. "This is the first approved drug to prevent recurrence for women who have had a singleton preterm baby and now have a singleton baby," he added. "That will dramatically [lower the] rate for those women."

Hydroxyprogesterone caproate has not been without some controversy. In 2006, an FDA advisory committee considering hydroxyprogesterone caproate to treat preterm birth brought up safety concerns, including a possible association with second trimester miscarriages.

Hydroxyprogesterone caproate is also the same drug as a much older one called Delalutin, which was approved by the FDA in 1956 and was used to treat female hormone disturbances and cancer, but withdrawn from the market for business reasons in 2008, the agency says.

"Makena is chemically the same as Delalutin," Burgess said.

What is new here is that a drug company will be making the drug; it won't have to be made up in pharmacies, according to Fleischman. "There will be consistency and high quality. This makes it a breakthrough not only that it's FDA approved and doctors will be comfortable in recommending it, but also there will be high quality and consistency for women as they take it," he said.

Dr. Gene Burkett, a professor of obstetrics and gynecology at the University of Miami Miller School of Medicine said that "this is something we have been using with women prone to preterm labor. It has been almost a standard of care for the last five or six years."

"Makena was approved under FDA's accelerated approval regulations, which allow promising drugs to be approved based on showing a benefit on a 'surrogate endpoint' that is likely to predict an actual clinical benefit," Burgess said. In this case, it was reducing the risk of delivery before 37 weeks.

Part of the terms of this approval require the manufacturer to conduct studies that demonstrate that the drug has a clinical benefit, she said.

In making its decision, the FDA reviewed data on the safety and effectiveness of Makena from a clinical trial that included 463 pregnant women who had a history of a spontaneous preterm birth.

Among those receiving Makena, 37 percent delivered before 37 weeks, compared with 55 percent of women who did not get the drug, the agency said.

Another study evaluated the development of children born to mothers enrolled in the first trial. Here, children ages 2.5 years to 5 years reached the same developmental targets, whether the mother was given the drug or not.

"The confirmatory study that is ongoing will be followed by a similar infant follow-up study, to be completed about 2018. That study is expected to include 580 to 750 infants, depending on the number of study sites and mothers willing to participate," the FDA says.

Makena is given by injection once a week from the 16th to the 37th week of pregnancy. Known by doctors as 17P, it is a synthetic form of a hormone produced during pregnancy.

Common side effects included pain, swelling or itching at the injection site; hives, nausea and diarrhea, according to the FDA. Serious adverse reactions are rare, although there was a report of a blood clot in the lungs and another of infection at the injection site, the agency noted.

The drug is being marketed by St. Louis-based KV Pharmaceutical.

More information

For more information on premature birth, visit the U.S. National Library of Medicine.