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.