USA: Study on Migraine and Pregnancy Complications

Recent data from the large prospective Nurses' Health Study II showed that women with a history of migraine had higher risks of pregnancy complications, including gestational hypertension, preterm delivery, and preeclampsia. Moreover, migraine with aura was tied to a somewhat higher preeclampsia risk.

The findings of the study were presented at the 2022 American Academy of Neurology meeting, held online and in Seattle by Alexandra Purdue-Smithe from Brigham and Women's Hospital in Boston.

Migraine is a neurovascular disorder that is two to three times more common in reproductive-age women than similarly aged men. Migraine and adverse pregnancy outcomes have similar pathophysiology, and both are associated with stroke and coronary heart disease. Migraine and adverse pregnancy outcomes may be linked, as suggested by some case-control and retrospective studies. However, prior studies lacked information on the aura, the migraine phenotype most strongly associated with vascular risk.

Against the above background, Dr. Purdue-Smithe and colleagues aimed to longitudinally examine associations between pre-pregnancy migraine, aura phenotype, and risk of adverse pregnancy outcomes.

For this purpose, the researchers estimated self-reported physician-diagnosed pre-pregnancy migraine associations with:

• Preterm delivery (<37 weeks)
• Gestational hypertension
• Gestational diabetes mellitus (GDM)
• Preeclampsia
• Low birth weight (<5.5 lbs)

among incident pregnancies in the longitudinal Nurses' Health Study 2 (n=30,555; 1989-2009). Log-binomial regression that accounted for multiple pregnancies per participant was used to estimate relative risks (RR).

Findings of the Study

In models adjusted for age, adiposity, and other behavioral and health factors, women with pre-pregnancy migraine (11%) exhibited higher risks of:

• Preterm delivery (RR=1.17)
• Gestational hypertension (RR=1.28)
• Preeclampsia (RR=1.40)

compared to women without pre-pregnancy migraine.

Pre-pregnancy migraine was not associated with low birth weight (RR=0.99) or GDM (RR=1.05).

Compared to women without pre-pregnancy migraine, the risk of preeclampsia was somewhat higher among women with migraine with aura (RR=1.51) than those with migraine without aura (RR=1.29).

Risks of other adverse pregnancy outcomes did not differ by aura phenotype.

"In this large, prospective study, pre-pregnancy migraine was associated with higher risks of gestational hypertension, preterm delivery, and preeclampsia," wrote the authors. "Migraine with aura was associated with a somewhat higher preeclampsia risk."

"Migraine history and phenotype may be important considerations in obstetric risk assessment and management," they concluded.

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