Is migraine tied to complications in pregnancy?

"Roughly 20% of women of childbearing age experience migraine, but the impact of migraine on pregnancy outcomes has not been well understood," said study author Alexandra Purdue-Smithe, Ph.D., of Brigham and Women's Hospital in Boston. "Our large prospective study found links between migraine and pregnancy complications that could help inform doctors and women with migraine of potential risks they should be aware of during pregnancy."

For the study, researchers looked at more than 30,000 pregnancies in roughly 19,000 women over a 20-year period. Of those pregnancies, 11% of the women reported that they were diagnosed by a doctor with migraine before pregnancy.

Researchers examined women's complications during pregnancy such as preterm delivery, defined as a baby born before 37 weeks gestation, gestational diabetes, gestational high blood pressure, preeclampsia, and low birthweight.

After adjusting for age, obesity, and other behavioral and health factors that could affect the risk of complications, researchers found that when compared to women without migraine, women with migraine had a 17% higher risk of preterm delivery, a 28% higher risk of gestational high blood pressure, and a 40% higher risk of preeclampsia. Of the 3,881 pregnancies among women with migraine, 10% were delivered preterm, compared to 8% of the pregnancies among women without migraine. For gestational high blood pressure, 7% of pregnancies among women with migraine developed this condition compared to 5% among pregnancies in women without migraine. For preeclampsia, 6% of pregnancies among women with migraine experienced it, compared to 3% of pregnancies among women who did not have migraine.

In addition, when looking at migraine with and without aura, women who had migraine with aura were 51% more likely to develop preeclampsia during pregnancy than women without migraine, while those who had migraine without aura were 29% more likely.

Researchers found that migraine was not associated with gestational diabetes or low birthweight.

"While the risks of these complications are still quite low overall, women with a history of migraine should be aware of and consult with their doctor on potential pregnancy risks," said Purdue-Smithe. "More research is needed to determine exactly why migraine may be associated with higher risks of complications. In the meantime, women with migraine may benefit from closer monitoring during pregnancy so that complications like preeclampsia can be identified and managed as soon as possible."

A limitation of the study was that although migraine history was reported prior to pregnancy, information on migraine aura was not collected until later in the study, after many of the pregnancies ended. So the findings for migraine aura may have been influenced by participants' ability to accurately remember their experiences. Another limitation is that information on migraine attack frequency and other migraine features was not available. Additional studies will be needed to address these limitations and better inform how pregnant women with a history of migraine should be screened and monitored for potential pregnancy complications.

The study was supported by the National Institutes of Health.