Born Too Soon

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Doctors admit that some of their best ideas for preventing early delivery haven't worked very well. A drug called Ritodrine, which was approved by the Food and Drug Administration in 1980, successfully stops preterm labor in many women, but subsequent studies have shown that it has no overall effect on a baby's health or survival. Treating all uterine infections, no matter how mild, also appears to make no difference on the timing of delivery — suggesting that infection is only one stage in a larger, much more complex process. "We've been taking the one-cause-at-a-time approach for 20 years," says Dr. Jay Iams at Ohio State University in Columbus. "But it doesn't work that way." Indeed, many researchers believe they won't really have a good grasp of how to prevent prematurity until they answer an even more fundamental question: How does a woman's body decide it's time to give birth in the first place?

One intervention has shown some promise in early trials of women with a history of premature delivery and no other known risk factors. Injecting these women once a week with the hormone progesterone reduces their chance of delivering early by a third. Researchers still don't quite understand why it works. The placenta produces a lot of the hormone, so it wouldn't seem that adding a little more would make a big difference. The treatment has not been studied in women who are carrying more than one child.

Caution may be in order. No one wants a repeat of the problems that happened with diethylstilbestrol (DES), a synthetic estrogen-like drug that was used in the 1950s and '60s to prevent premature delivery and turned out to cause, among other things, reproductive-tract abnormalities and a rare cancer. Unlike DES, however, progesterone has a long safety record. And it is not being used in the earliest days of pregnancy, when birth defects are more likely to occur. What progesterone doesn't have is a major manufacturer, because the drug is not protected by a patent. Instead it is usually produced in small batches at compounding pharmacies.

Anyone who has ever cared for an extremely premature infant knows the stakes are high. Doctors can sustain a tiny baby with severe bleeding in the brain, with lungs so fragile that even the gentlest respirator can permanently damage them. But should they? "That's when neonatology becomes a difficult and ethically fraught field," says Dr. Myra Wyckoff of the University of Texas Southwestern Health Science Center in Dallas. No matter how you answer the question, surely the best solution is to find a way to reduce the number of extremely premature births from happening in the first place.