Risk factors for pre-eclampsia: a study in Tehran, Iran.

This study evaluated some risk factors for pre-eclampsia, which is one of the most problematic complications of pregnancy. This was a retrospective case control study conducted on 318 pre-eclamptic women (case group) and 318 women who were normotensive at the time of delivery as the control group. Evaluated factors were: maternal age, gestational age, nuliparity, mother's educational status, maternal body mass index (BMI), maternal hemoglobin and blood Rh, familial history of pre-eclampsia, history of pre-eclampsia in a previous pregnancy, marital relations, urinary infection (UTI) during the present pregnancy, season of delivery, and method of contraception. Risk factors for pre-eclampsia were: UTI (P=0.04); history of pre-eclampsia during previous pregnancy (P=0.003), and winter season (P=0.001). Maternal age of more than 20 years, high educational status of mother, parity more than one, and oral contraceptive pills were protective for pre-eclampsia. After adjusting for all possible confounding factors using multiple logistic regression, only preexisting pre-eclampsia (P=0.004) was a risk factor, whereas parity more than three (P=0.007) and anemia (P=0.01) were protective for pre-eclampsia. The rate of cesarean delivery was more common in the pre-eclamptic group (245 cases, 77%) than the control group (85 cases, 26.7%). The one minute Apgar score of neonates less than 8 was more common in the case group (28.6% vs. 47.4%, P<0.001). Gestational age at the time of delivery was lower in the case group (36.48±3.4 weeks vs. 37.12±3.3 weeks, P<0.001). Awareness of risk factors of pre-eclampsia can help to monitor patients, ensure earlier diagnosis and predict which patients are more likely to develop pre-eclampsia.