Is new onset hypertension in obese women more likely to be Gestational Hypertension? - A retrospective study

INTRODUCTION: New onset hypertension is more common in antenatal women with increased Body Mass Index (BMI). This may be due to either gestational hypertension (GH) or pre-eclampsia (PE). GH unlike PE is not associated with poor perinatal outcomes and would not require interventions such as increased antenatal visits and induction of labour. Our study assessed the prevalence of GH and PE in women with increased BMI as compared to women with normal BMI. SETTING AND DESIGN: Historical cohort of a large tertiary centre. METHOD AND MATERIALS: Data from the electronic birth registry of the labour room was used to identify women who had a BMI ≥ 35 kg/m2 at delivery. Women with a normal BMI matched for the mode of delivery was taken as control. 148 women with BMI ≥ 35 kg/m2 were compared with 140 women of normal BMI. RESULTS: New onset hypertension was seen in 41.2% (61/148) and 8.6% (12/140) in the non-obese group RR 4.81 (2.7-8.54) P (<0.001). GH was seen in 24.3% in obese women and 2.9% in normal controls, RR (9.65 (3.54,26.34)), P (<0.001). PE was seen in 16.9% of obese women and 5.7% of women with normal BMI, RR (3.79 (1.78,8.08)) P (<0.001). Proportion of GH in women with new onset hypertension was seen in 59% of obese women with new onset hypertension and 33% of normal controls. CONCLUSION: This clinically relevant trend towards an increased proportion of GH highlights the importance of identifying pathophysiological mechanism for high BP in obesity when there is new onset hypertension.