Hypertensive disorders in pregnancy: Frequency and associated factors in a cohort of Brazilian women

Objective. To evaluate the frequency of and risk factors associated with hypertensive disorders in general antenatal care in five distinct areas of Brazil. Methods. We performed a cohort study of 4892 women enrolled in midpregnancy from 1991 to 1995. Patients were queried at enrollment about hypertension prior to pregnancy. Medical diagnoses of hypertensive disorders in pregnancy were abstracted from patient records. Hypertensive disorders in pregnancy were classified according to recommendations of the American College of Obstetrics and Gynecology (AGOG). Results. Of 4892 women studied, 367 (7.5%) presented hypertensive disorders, 113 (2.3%) being preeclampsia/eclampsia and 198 (4.0%) chronic hypertension. Frequencies of superimposed preeclampsia/eclampsia and transitory hypertension were 0.5% and 0.7%, respectively. Greater brachial arm circumference was strongly associated both with preeclampsia/eclampsia and with chronic hypertension (threefold difference across extreme quartiles, p less than or equal to 0.001). In adjusted analyses, being older, black, and obese were important and statistically significant risk factors for chronic hypertension. Similarly, nulliparity was a statistically significant risk factor for preeclampsia/eclampsia. and tendencies toward increased risk were seen for older, black, and obese women in adjusted analyses. Preeclampsia/eclampsia and chronic hypertension were notably less frequent in Manaus, although regional differences were statistically significant only for chronic hypertension. Conclusions. Hypertensive disorders commonly complicate pregnancy in Brazilian women. Risk factors for these disorders appear similar to those reported in other countries. Use of an inappropriately sized cuff to measure blood pressure may result in many false-positive diagnoses in more obese women. The considerably lower frequency of hypertensive disorders found in Manaus, in the Amazon region, warrants further study.