Independent risk factor?
In the past, it has been somewhat unclear whether migraine is an independent risk factor for these complications or whether women with migraine just have greater risk factors for adverse pregnancy outcomes.
“Our preliminary findings suggest that migraine is independently associated with these adverse pregnancy outcomes, or at least that’s what it seems,” said Dr. Purdue-Smithe.
The new results could be used by clinicians to “flag” women who may be at risk for complications, she added. “These women may benefit from closer monitoring in pregnancy so that if issues arise, physicians can act quickly.”
She noted that preeclampsia “can come on suddenly and escalate rapidly,” and there are few interventions to treat it besides delivery.
However, low-dose aspirin may be worth investigating. Various health care groups and the U.S. Preventive Services Task Force recommend pregnant women at high risk for preeclampsia take low-dose aspirin (81 mg/d) after 12 weeks’ gestation.
“It would be interesting to see if women with migraine who take aspirin in pregnancy can reduce their risk of preeclampsia, and future research should address this question,” said Dr. Purdue-Smithe.
Additional testing showed that associations with preeclampsia and gestational hypertension did not vary according to age and other obstetrical risks.
The Nurses’ Health Study II did not have information on number and severity of migraine attacks, so the researchers were unable to determine if these factors affect pregnancy outcomes.
“Understanding whether specific migraine features, such as attack frequency, are associated with adverse pregnancy outcomes will be an important area for future research,” said Dr. Purdue-Smithe. She noted prior studies showed the frequency of migraine attacks is related to ischemic stroke and other cardiovascular outcomes.
The authors acknowledged a limitation for the current study: Although migraine history was reported prior to pregnancy, information on migraine aura was collected after most of the pregnancies in the cohort were over. So the findings for migraine aura may have been influenced by participants’ ability to accurately remember their experiences.
Collaboration is key
Commenting on the research, Nina Riggins, MD, PhD, director of the Headache and Traumatic Brain Injury Center in the department of neurosciences at the University of California, San Diego, said the study “stands out” because it distinguishes pregnancy complications between those with and without aura among women with migraine.
Dr. Riggins noted the investigators found the risk of preeclampsia, which on average occurs in about 3%-5% of pregnancies, is higher among women with migraine with aura.
“The good news is that treatments are available,” she said. “Preconception planning should include this discussion for patients living with migraine.”
However, the study did not compare risks for patients who have frequent migraine attacks versus episodic migraine, Dr. Riggins noted. “We need to learn more about whether any treatments can be safe and effective to decrease risks of complications during pregnancy in this population,” she said.
“I believe, ultimately, what this study reveals is that collaboration among primary care, ob.gyn., maternal-fetal medicine specialists, and neurologists will likely benefit pregnant patients with migraine,” Dr. Riggins said.
The study received funding from the National Institutes of Health. Dr. Purdue-Smithe has disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.