When It Comes to Pregnancy, Timing Is Everything

By Kathleen Doheny
HealthDay Reporter
Friday, April 4, 2008; 4:00 AM

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THURSDAY, April 3 (HeathDay News) -- First, there's the initial baby question: When is the right time to have your first child?

Turns out, that's just the beginning. Equally important is figuring out when to have the next baby -- if you decide to have more than one.

The proper timing of pregnancies, experts say, can decrease your risk of having a baby born premature and with a host of health problems.

Intervals that are too brief -- as well as those that are too long -- aren't desirable, research suggests.

In one of the latest studies, researchers from Washington University in St. Louis evaluated more than 156,000 women from Missouri who had two births from 1989 to 1997. The researchers looked at the intervals between pregnancies and the outcomes for those pregnancies. The study, led by Dr. Emily DeFranco, a clinical fellow in maternal-fetal medicine and a staff member at Washington University's Center for Preterm Birth Research, was published recently in the American Journal of Obstetrics and Gynecology.

Among the findings, according to DeFranco:

• Intervals of less than six months from delivery to conception of the next baby increased the risk of preterm birth (less than 35 weeks) by 41 percent.
• Intervals of six to 12 months increased preterm birth risk by 14 percent.
• Intervals of 12 to 18 months carried no significant increased risk of preterm birth.

"Wait a minimum of 12 months before becoming pregnant again," DeFranco advised. That's to say, let 12 months or more go by after delivery before you start trying again to become pregnant. That advice is especially crucial for women who have already had a preterm birth, which raises the preterm risk in subsequent pregnancies, she said.

In another report, published in April 2006 in the Journal of the American Medical Association, researchers from Bogota, Colombia, reviewed the results of 22 published studies, coming to conclusions similar to those of the Missouri researchers. But the Colombian researchers also found hazards with intervals that were too lengthy.