There is some evidence to suggest that women who suffer from migraines may be at a slightly increased risk for certain pregnancy complications. For example, studies have shown that women who have a history of migraines may be more likely to experience pregnancy-related hypertension, preeclampsia, and gestational diabetes. Additionally, women with migraines may be at a slightly increased risk for preterm delivery, low birth weight babies, and cesarean section.
Women are disproportionately affected by migraine, particularly during their reproductive years. However, the link between migraine and adverse pregnancy outcomes is not well understood. A new study from Brigham and Women’s Hospital, a founding member of the Mass General Brigham healthcare system, analyzed data from thousands of women in the Nurses’ Health Study II to assess the relationship between migraine and pregnancy complications.
The team reports in Neurology that migraine diagnosed prior to pregnancy was linked to adverse pregnancy outcomes such as preterm delivery, gestational hypertension, and preeclampsia, suggesting that migraine may be a clinical marker of elevated obstetric risk.
Our findings of reduced risk of preterm delivery among women with migraine who reported regular aspirin use prior to pregnancy suggests that aspirin may also be beneficial for women with migraine.
Alexandra Purdue-Smithe
“Preterm delivery and hypertensive disorders are some of the primary drivers of maternal and infant morbidity and mortality,” said first author Alexandra Purdue-Smithe, Ph.D., an associate epidemiologist at Brigham and Women’s Hospital and a Harvard Medical School instructor in Medicine. “Our findings suggest that a history of migraine is an important risk factor for these complications and could be useful in identifying women who may benefit from increased monitoring during pregnancy.”
Women are two to three times more likely than men to suffer from migraine in their lifetime, and migraine is most common in women aged 18 to 44. Aura, which are usually visual disturbances that appear prior to headache onset, can accompany migraine headaches in some people.
Previous research has linked adverse pregnancy outcomes and migraine, particularly migraine with aura, to an increased risk of coronary heart disease and ischemic stroke in women. These risks’ underlying biology may also increase the likelihood of pregnancy complications. However, only a few small or retrospective studies have looked at migraine as a risk factor for pregnancy complications to date. There have been no prospective studies that have looked at risks based on aura phenotype (migraine with versus without aura).
Purdue-Smithe and colleagues examined data from the large, prospective Nurses’ Health Study II, which included 30,555 pregnancies from 19,694 United States nurses. The researchers examined pre-pregnancy self-reported physician-diagnosed migraine, migraine phenotype (migraine with and without aura), and self-reported pregnancy outcomes.
Researchers were able to control for potential confounding factors such as body mass index, chronic hypertension, and smoking in their analyses due to the large size of the study population and the availability of data on other health and behavioral factors.
Researchers found that pre-pregnancy migraine was associated with a 17 percent higher risk of preterm delivery, 28 percent higher rate of gestational hypertension, and 40 percent higher rate of preeclampsia compared to no migraine. Migraine with aura was associated with a somewhat higher risk of preeclampsia than migraine without aura. Migraine was not associated with low birth weight or gestational diabetes mellitus.
Participants with migraine who used aspirin regularly (at least twice a week) prior to pregnancy had a 45 percent lower risk of preterm delivery. Individuals at high risk of preeclampsia and those with more than one moderate risk factor for preeclampsia should take low-dose aspirin during pregnancy, according to the US Preventive Services Task Force. Low-dose aspirin during pregnancy has also been shown in clinical trials to reduce preterm birth rates. However, Purdue-Smithe points out that migraine is not currently listed as an indication for aspirin use during pregnancy.
“Our findings of reduced risk of preterm delivery among women with migraine who reported regular aspirin use prior to pregnancy suggests that aspirin may also be beneficial for women with migraine. Given the observational nature of our study, and the lack of detailed information on aspirin dosage available in the cohort, clinical trials will be needed to definitively answer this question.”
Other study limitations include the fact that participants only reported if they had a physician-diagnosed migraine, likely excluding those who did not have chronic or severe migraine. Furthermore, aura was assessed after the migraine diagnosis and after many of the pregnancies in the cohort, which may have resulted in some degree of reverse causation in migraine phenotype analyses. Furthermore, the cohort study is made up primarily of non-Hispanic white people with relatively high socioeconomic status and health literacy, which may limit generalizability.
