Migraine History May Be a Risk Factor for Pregnancy Complications: New Findings

A history of migraine headache may increase a woman’s risk of adverse pregnancy outcomes, according to findings of a research team from Brigham and Women’s Hospital (BWH) in Boston.

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The investigators analyzed data from more than 19 000 women participating in the Nurses’ Health Study II and found specifically that prepregnancy migraine was associated with a 17% higher rate of preterm delivery, a 28% higher rate of gestational hypertension, and a 40% higher rate of preeclampsia compared with no migraine. The results, they say, suggest that migraine may be a clinical marker of elevated obstetric risk.

“Preterm delivery and hypertensive disorders are some of the primary drivers of maternal and infant morbidity and mortality,” said first study author Alexandra Purdue-Smithe, PhD, associate epidemiologist at BWH and instructor in Medicine at Harvard Medical School in a BWH press announcement. “Our findings suggest that a history of migraine warrants consideration as an important risk factor for these complications and could be useful in flagging women who may benefit from enhanced monitoring during pregnancy.”

Women are disproportionately affected by migraine and particularly during child-bearing years, observe Purdue-Smithe and colleagues, writing in the journal Neurology. The relationship between migraine and adverse pregnancy outcomes, however, has not been well studied. To date the few studies that have been done have been small and retrospective in nature.

“Our findings suggest that a history of migraine warrants consideration as an important risk factor for these complications and could be useful in flagging women who may benefit from enhanced monitoring during pregnancy.”

The BWH team analyzed data from the landmark, prospective Nurses' Health Study II, which included 30 555 pregnancies from 19 694 US nurses. Participants had no history of cardiovascular disease, diabetes, or cancer. Investigators evaluated prepregnancy self-reported physician-diagnosed migraine and migraine phenotype (migraine with and without aura) and incidence of self-reported adverse pregnancy outcomes.

FINDINGS

Among the full cohort, 11% of participants reported physician-diagnosed migraine. The investigators found, after adjusting for potential confounding variables including age, adiposity, and other health and behavioral factors, that among those with prepregnancy migraine the diagnosis was associated with increased risks for preterm delivery (RR, 1.17; 95% CI, 1.05- 1.30), gestational hypertension (RR, 1.28; 95% CI, 1.11-1.48), and preeclampsia (RR, 1.40; 95% CI, 1.19,-1.65) compared to those who reported no migraine.

According to study findings, migraine history was not associated with low birthweight (RR, 0.99; 95% CI, 0.85-1.16) or gestational diabetes (RR, 1.05; 95% CI, 0.91-1.22).

When they assessed incidence of adverse pregnancy outcomes by migraine phenotype, researchers found the risk of preeclampsia was somewhat higher among participants with migraine with aura (RR, 1.51; 95% CI, 1.22- 1.88) than migraine without aura (RR, 1.30; 95% CI, 1.04-1.61; Pheterogeneity=0.32). Other outcomes were found similar by phenotype.

Low-dose aspirin?

For women at high risk of preeclampsia and also for those who have >1 moderate risk factor for preeclampsia the US Preventive Services Task Force recommends low-dose aspirin during pregnancy, according to study authors. There are data from trials that have shown low-dose aspirin effective at reducing rates of preterm birth as well.

When Purdue-Smith and colleagues evaluated data from study participants with migraine who reported regular pre-pregnancy aspirin use (≥2x/week) they found lower risks of preterm delivery (RR, 0.55; 95% CI, 0.35-0.86; P_interaction<.01) and for preeclampsia (≥2x/wk RR, 1.10; 95% CI, 0.62-1.96; P_interaction=.39) than among those who did not use aspirin. The investigators note, however, there was limited statistical power for the stratified analyses.

“Migraine history, and to a lesser extent migraine phenotype, appear to be important considerations in obstetric risk assessment and management. Future research should determine whether aspirin prophylaxis may be beneficial for preventing adverse pregnancy outcomes among pregnant individuals with a history of migraine,” the team concluded.

Among the study’s limitations the authors note the observational design and the homogenous composition of the cohort, ie, majority White, relatively high socioeconomic status and health literacy. In addition, self-report of migraine did not include headache severity. Each of these could reduce the likelihood that the findings are generalizable outside the study.

Purdue-Smithe AC, Stuart JJ, Farland LV, et al. Prepregnancy migraine, migraine phenotype, and risk of adverse pregnancy outcomes. Neurology. Published online January 19, 2023. doi:10.1212/WNL.0000000000206831