(HealthDay News) – Women who have had induced abortions (IAs) have an increased likelihood of having a very premature or low birth weight first baby, and the likelihood increases with each IA, according to research published online Aug 29 in Human Reproduction.

To examine whether the perinatal health of first-born children is affected by the mother’s previous IAs, Reija Klemetti, PhD, of the National Institute for Health and Welfare in Helsinki, and colleagues conducted an observational study using a nationwide registry of 300,858 first-time mothers who gave birth between 1996 and 2009.

The researchers found that 10.3% of the first-time mothers had one, 1.5% had two, and 0.3% had three or more IAs. The likelihood of very preterm birth (<28 weeks of gestation) was increased after IA, showing a dose-response association: odds ratio, 1.19 after one IA; 1.69 after two IAs; and 2.78 after three IAs. For mothers who had three or more IAs, the odds of preterm birth (<37 weeks), birth weight <2,500g, and birth weight <1,500g were significantly increased (odds ratio, 1.35, 1.43, and 2.25, respectively).

“From a public health perspective, information on increased risk of very preterm birth after IAs and its dose-response effect is intrinsically important,” the authors write. “In terms of practical implications, it must be noted that observational studies like ours, however large and well-controlled, will not prove causality.”

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