Risk factors for hypertension during pregnancy in South Australia

Abstract

Objective: To identify risk factors for hypertension in pregnancy among South Australian women. Design: A population-based retrospective analysis using the South Australian perinatal data collection for 1998–2001. Methods: Three groups of women with hypertension (pre-existing hypertension, pregnancy hypertension, and superimposed pre-eclampsia) were compared with normotensive women using unconditional logistic regression analysis on 70 386 singleton births to identify sociodemographic and clinical risk factors for hypertension in pregnancy. Results: Nulliparity, Aboriginal race and Caucasian race (compared with Asian) and pre-existing and gestational diabetes were demonstrated to be risk factors for all hypertensive disorders, as was increasing maternal age for pre-existing hypertension and superimposed pre-eclampsia. Risk was increased for pregnancy hypertension and superimposed pre-eclampsia among women who gave their occupation as ‘home duties’ and also for superimposed pre-eclampsia among unemployed women. Women with hypertension were more likely to give birth in teaching hospitals. Urinary tract infections were not found to be a risk factor for any type of hypertension. Smoking during pregnancy was protective for all types of hypertension. Conclusions: The present study used a statewide population perinatal database and has confirmed that Aboriginal race, Caucasians, nulliparity, and pre-existing and gestational diabetes are independent risk factors for all types of hypertension in pregnancy. Increasing maternal age increased the risk for pre-existing hypertension and superimposed pre-eclampsia. There appeared to be appropriate referral of women with hypertensive disorders to teaching hospitals. A new finding is the increased risk among unemployed women and women engaged in home duties.