The Puzzle of Preterm Birth
By Craig L. Bissinger
Preterm birth is one of the most troubling problems facing obstetricians. Nearly 11 percent of all babies born in the United States will be delivered before the 37th week of pregnancy. Despite our knowledge and technological advances, we have been unable to reduce premature birth rates over the past 40 years.

Most of our successes with premature babies have come thanks to the efforts of our pediatric friends in the Neonatal Intensive Care Units. This is not to say that all these babies do great, but the vast majority thrive.

Our greatest concern is for babies born before 32 weeks. Although they account for just 1 to 2 percent of deliveries, they make up half of all the all birth complications.

We know that there are factors that put women at risk for preterm birth. These include lower socioeconomic class, excessive weight gain, a history of premature birth, smoking, a multiple pregnancy, kidney infections and other medical conditions, such as diabetes or high blood pressure. And yet, even with this information, we don’t do a very good job of preventing premature labor.

Another problem is that we don’t fully understand why women go into premature labor. Some doctors believe that vaginal infections are a substantial cause, while others believe that labor begins once the uterus grows to full-term size. Whatever the reason, we haven’t discovered an effective way to prevent or stop premature labor.

The signs of premature labor may include regular, painful uterine contractions; intermittent low back pains; increasing vaginal pressure, or increasing vaginal discharge. If you experience any of these symptoms, you should call your physician. Your doctor will probably send you to the hospital, where fetal monitoring and a pelvic examination will help determine what’s happening. Observing a patient is the best way to make the correct diagnosis.

I should point out that it’s very hard to detect the difference between false labor and genuine labor pains. That’s why I tell my patients that it is always OK to call. I’d rather they err on the safe side and let me make the decision.

Pregnant women should also know that there’s a new test to help determine if a woman is in premature labor. It’s called fetal fibronectin, and it relies on a swab of vaginal secretion to help solve the mystery. A negative test result means that the woman has less than a 1 percent chance of delivering her baby within the next week. In this case, we believe she was in false labor. Those with a positive test have a 20 percent chance of delivering within one week.

If we suspect that a patient is in premature labor, especially under 34 weeks, we have one major objective. We want to prevent labor for 48 hours so we can give corticosteroids to the mom. Research has proven that after two days this medication helps “significantly reduce the risk of respiratory distress syndrome, brain hemorrhages and neonatal death.”(National Institutes of Health, 1994).

Still, medication to stop preterm labor doesn’t work long-term. Studies have shown that it can extend a pregnancy by six days at most. I should also mention that these medications can have unpleasant side effects, so we must weigh the risks and the benefits.

Recently there has been talk about progesterone being helpful in reducing premature births. Research is currently taking place to evaluate whether it’s effective.

It’s very important to deliver a premature baby at a hospital whose staff has the expertise to care for the special needs of these children. This is the main reason women are often transferred to these high-risk centers before delivery. Premature babies often make for complicated deliveries because they may be breech (buttocks first), very small or experience stress during labor. In these situations, a Caesarean section is performed to give the baby the best chance to thrive.

All obstetricians pray for the day when the last premature baby is born. Until that time, we ask our patients to be attentive to their bodies. Listen to yours, and call us if you have any concerns.