The association of maternal chronic hypertension with perinatal death in male and female offspring:: a record linkage study of 866 188 women

Objective The purpose of this study was to determine whether there is a difference, by gender, in perinatal mortality in chronically hypertensive women compared with normotensive women. Design Population-based prospective cohort study. Setting Sweden. Population A total of 866 188 women with singleton pregnancies registered in the Swedish Medical Birth Registry 1992-2004, of which 4749 were diagnosed with chronic hypertension. Methods Multivariate logistic regression analysis was performed. In a first step, we adjusted for maternal characteristics and in a second step for mild and severe pre-eclampsia, gestational diabetes, placental abruption and small for gestational age. An effect modification by gender was included in the model. Main outcome measures Odds ratios (OR) for intrauterine death, neonatal death and post-neonatal death with respect to gender of offspring. Results The unadjusted OR of intrauterine death was 4.12 (95% CI: 2.84-5.96) and 1.29 (95% CI: 0.67-2.48) for male and female offspring, respectively, and of neonatal death, it was 3.45 (95% CI: 2.13-5.59) and 2.17 (95% CI: 1.08-4.35) for male and female offspring, respectively. After multivariate analysis, the OR of intrauterine death was 3.07 (95% CI: 2.12-4.46) and neonatal death was 2.99 (95% CI: 1.84-4.85) for male offspring. For female offspring, the OR of intrauterine death was 0.98 (95% CI: 0.51-1.89) and neonatal death was 1.88 (95% CI: 0.93-3.79). Conclusion Mothers with chronic hypertension have an increased risk of perinatal mortality of their male offspring.