Trimester-specific blood pressure levels and hypertensive disorders among pregnant migraineurs

Objective.- We evaluated the influence of physician-diagnosed migraine on blood pressure levels and the risk of hypertensive disorders of pregnancy in a clinic-based prospective cohort study of 3373 healthy pregnant women. Background.- The relationship between migraine and blood pressure is controversial with results from several studies suggesting positive associations, while others suggest null or inverse associations. To our knowledge, no previous study has investigated blood pressure profiles among pregnant migraineurs. Methods.- We abstracted blood pressure values and delivery information from medical records of women presenting to prenatal clinics in Washington State. Mean blood pressure differences for pregnant migraineurs and non-migraineurs were estimated in regression models, using generalized estimating equations. We calculated odds ratios and 95% confidence intervals (95% CIs) for gestational hypertension and preeclampsia in relation to migraine status. Results.- Mean first, second, and third trimester systolic blood pressures (SBP) were elevated among pregnant migraineurs as compared with non-migraineurs. Migraineurs had higher mean third trimester SBP (4.08 mmHg) than non-migraineurs. Trimester-specific diastolic blood pressure (DBP) values were variably related with migraine status. Mean first (0.82 mmHg) and third (2.39 mmHg) trimester DBP were higher, and second trimester DBP values were lower (-0.24) among migraineurs as compared with non-migraineurs. Migraineurs had a 1.53-fold increased odds of preeclampsia (95% CI 1.09 to 2.16). Additionally, migraineurs who were overweight or obese had a 6.10-fold increased odds of preeclampsia (95% CI 3.83 to 9.75) as compared with lean non-migraineurs. Conclusions.- Pregnant migraineurs had elevated blood pressures, particularly SBP measured in the third trimester, and a higher risk of preeclampsia than pregnant women without migraine. Observed associations were more pronounced among overweight or obese migraineurs. Our findings add to the accumulating evidence of adverse pregnancy outcomes among migraineurs.