, according to results from an observational study.
Migraine during pregnancy has been associated in previous studies with hypertensive pregnancy complications including preeclampsia; however, little is known about other headache types and their effects on pregnancy and birth outcomes.
For their research, published online July 20 in Cephalalgia, Isabella Neri, MD, PhD, and colleagues at Hospital Policlinico of Modena, Italy, looked at headache status for 515 consecutive pregnant women evaluated during their first trimester and followed through childbirth.
Altogether 224 women, or 43.5% of the cohort, were diagnosed with migraine without aura (n = 72), migraine with aura (n = 27), or tension-type headache (n = 125). The authors did not report on the severity or frequency of headaches.
Women with migraine with aura and tension-type headache saw higher rates of small-for-gestational-age infants (25.9% and 10.4% of births, respectively) compared with 5.5% for women without headache. Women presenting with tension-type headache saw elevated risk for small-for-gestational-age infants (odds ratio [OR] 4.19, P = .004) as did women with migraine with aura (OR 5.37, P = .02).
Admission to neonatal intensive care was significantly higher in all the headache groups. However, the authors found no statistically significant associations between headaches and any other perinatal outcome investigated in the study, including gestational diabetes, placental abruption, gestational hypertension, and preterm delivery.
A previous study conducted by the same research group had reported a relationship between migraine and gestational hypertension. The authors cited the small sample size of the migraine groups in the current study, “the diverse features of the population,” and the popularity of low-dose aspirin administration as potentially affecting that outcome.
Interpret findings with caution
Asked by this news organization to comment on the research, two headache neurologists praised Dr. Neri and colleagues’ research for focusing on an understudied topic – but also said that the results would not change their practice unless replicated in larger studies.
Elizabeth W. Loder, MD, MPH, chief emeritus of the division of headache at Brigham and Women’s Faulkner Hospital in Boston, urged caution in interpreting the findings, particularly with regard to tension-type headache. “This study adds to information suggesting that pregnancy complications probably are higher in women who have migraine with aura, and there’s biological plausibility for that,” Dr. Loder said. “Having aura means you may have some vascular abnormalities and things that logically might be associated with an increased risk of small-for-gestational age infants.” But the small size of the migraine-with-aura group in this study – 27 women – and the fact that other perinatal outcomes measured in the study did not reach significance, allows for the possibility that the small-for-gestational-age findings were due to chance, Dr. Loder noted.
With tension-type headache, a biological rationale for small-for-gestational-age risk is more elusive, Dr. Loder said. “I would want to see that association replicated in another study before I thought that I needed to warn women with tension-type headache about this potential outcome. There’s lot of uncertainty here about the magnitude of the risk.”
While Dr. Neri and colleagues described the instruments used in their study to diagnose migraine and migraine with aura, they did not explain how tension-type headache was diagnosed.
Tension-type headache, while common, is still not well characterized, Dr. Loder noted, and may represent a heterogeneous condition or the milder end of a biological continuum that includes migraine with aura. Also, the group in the study had a higher prevalence of smoking, and though the authors made statistical adjustments for smoking status, “smokers are systematically different than people who aren’t in other ways that could be associated with these outcomes,” Dr. Loder said.
While the authors of the study suggested that interventions might be indicated for women with tension-type headache in pregnancy, “showing an association doesn’t necessarily mean that intervening would make a difference” on pregnancy outcomes, Dr. Loder said.
Amaal J. Starling, MD, of the Mayo Clinic in Phoenix, Ariz., said in an interview that she, too, appreciated that this study looked at pregnancy outcomes in the setting of headache disorders. “Unfortunately even though headache disorders and especially migraine affect women so much, we still know very little about migraine in pregnancy,” she said.
Dr. Starling noted that many women with migraine are discouraged by their health care providers from becoming pregnant, because of the false belief that migraine cannot be managed in pregnancy. In her own practice, she said, she treats many patients with severe headache who become pregnant and who require pharmacological intervention during pregnancy.
This does not mean she regards headache in pregnancy as innocent. “I want patients to be on high alert for changes in headache symptoms in pregnancy. If someone has worsening of headache or migraine or aura in the setting of pregnancy, we consider that a red flag,” potentially indicating complications such as high blood pressure, gestational hypertension, or a blood clot.
Like Dr. Loder, Dr. Starling said she was not surprised by Dr. Neri and colleagues’ finding that migraine with aura might impact pregnancy outcomes. “We know that migraine with aura has a lot of vascular abnormalities that underlie the pathogenesis,” she said.
Dr. Starling found the findings related to tension-type headache less convincing, not least because the diagnostic criteria for tension-type headache was not made clear in the study. “I view this as an exploratory study that says maybe there’s a signal here. A larger epidemiological study would need to be done to confirm or refute this data,” Dr. Starling said. Until the findings can be replicated, “this study would not affect my clinical practice in any way.”
Dr. Neri and colleagues described no outside funding for their research or financial conflicts of interest. Dr. Starling has received consulting fees from pharmaceutical manufacturers but reported no disclosures relevant to the study discussed. Dr. Loder reported no financial conflicts of interest.