A Prospective Study of Adverse Pregnancy Outcomes Among Planned and Unplanned Pregnancies in Natural Family Planning Users

Abstract

Objectives. To prospectively determine whether unplanned pregnancies are associated with adverse pregnancy outcomes among users of natural family planning (NFP).

Methods. Women who became pregnant while using NFP were identified in five centers worldwide: there were 373 unplanned and 367 planned pregnancies. Subjects were followed up at 16 and 32 weeks gestation and after delivery. The risks of spontaneous abortion, low birth weight and preterm birth were estimated after adjustment by logistic regression.

Results. The women with unplanned pregnancies were more likely to be at the extremes of age, to report more medical problems before and during the index pregnancy, and to seek antenatal care later in gestation than the women with planned pregnancies. However, women with planned pregnancies reported a higher rate of spontaneous abortion in prior pregnancies (28.8%) than did women with unplanned pregnancies (12.9%, p<0.001). There were no significant differences in the rates of spontaneous abortion, low birth weight or preterm birth in the two groups.

Conclusions. No increased risk of adverse pregnancy outcomes was observed among women who experienced an unplanned pregnancy during NFP use. (Am J Public Health. 1996:00:0000-0000).