An association between maternal smoking and preeclampsia in Japanese women.

In order to determine whether maternal smoking before or during pregnancy, or both, is associated with a reduced risk for preeclampsia in Japanese subjects, we conducted a case-control study that took other risk factors for preeclampsia into consideration. Seventy-one preeclampsia patients were matched with 142 controls for parity and age. Information from a self-administered questionnaire and clinical data such as maternal age, parity, family history of hypertension, prepregnancy body mass index (BMI), and pregnancy outcomes were analyzed. No significant difference was found between the groups in smoking rates before and during pregnancy (38.0 and 18.3% in preeclampsia patients and 38.0 and 16.9% in controls, respectively). However, classification of the subjects according to the presence of "prepregnancy high body mass (BMI > or = 24)" revealed a significant association between maternal smoking before pregnancy and preeclampsia in women with a prepregnancy high body mass (a smoking rate of 47.6% in patients with preeclampsia and 7.1% in controls, p < 0.05). This result suggests that there is a clear racial difference in the manifestation of preeclampsia with respect to the effect of smoking and that early intervention, particularly before pregnancy, to get obese women to stop smoking may be effective for preventing preeclampsia.