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Risk factors for hypertension during pregnancy in South Australia


Professor Gus A. Dekker, Department of Obstetrics and Gynaecology, University of Adelaide, Lyell McEwin Health Service, Haydown Road, Elizabeth Vale, South Australia 5112, Australia. Email:


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.