Date of Award

6-3-2009

Document Type

Thesis

Degree Name

Medical Doctor (MD)

First Advisor

Edmund Funai

Abstract

Recent data have shown increased maternal mortality rates and cardiovascular disease after hypertensive disorders of pregnancy (HDP), but the reasons for this increase remain unclear. This study investigates the effects of a prepregnancy cardiovascular risk factor, namely body mass index (BMI), on the relationship between HDP and postpregnancy mortality. Data came from a 1975-1976 subset (n=13,722) of a population-based cohort of women. Multiple logistic regression was used to examine the risk of HDP by BMI by calculating odds ratios (OR) and 95% confidence intervals (CI). Age-adjusted Cox proportional hazards models were used to examine survival rates by calculation of the hazard ratios (HR) and 95% CIs. Normal weight was defined as BMI 18.5-24.9 kg/m2, overweight as BMI 25-29.9 kg/m2 and obesity as BMI ≥ 30 kg/m2. Women who entered their pregnancy overweight or obese had increased HDP [OR 2.82 (95% CI: 2.40, 3.31) and OR 5.51 (4.51, 7.31)] and decreased survival [HR 1.42 (1.10, 1.83) and HR 2.43 (1.61, 3.68)] when compared to normal weight women. HDP were associated with increased mortality in women who survived >15 years [HR 1.94 (1.42, 2.67)] and that association remained significant, although attenuated, after adjustment for BMI [HR 1.65 (1.19, 2.79)]. The risk of death after HDP was increased in women who entered their pregnancy being overweight [HR 1.86 (1.07, 3.20)] or obese [HR 2.90 (1.28, 6.58)] as compared to the normal weight women [HR 1.26 (0.74, 2.14)]. Elevated prepregnancy BMI is associated with increased risk of HDP, which are known to be associated with an increased risk of maternal mortality. The association between HDP and mortality is increased in women entering pregnancy with elevated BMI. While obesity is a known cardiovascular risk factor, it does not fully explain the association between HDP and later life maternal disease. These data suggest that women with HDP should be followed after their pregnancy and appropriate interventions initiated to increase their long-term survival.

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