Women With Migraines During Pregnancy May Have Increased Risk of Complications

Some women see their migraines improve while they are pregnant, but for those who don't, a new study said there are greater risks of several adverse pregnancy outcomes, both for them and their infants, than women without migraine. Risks include elevated blood pressure, miscarriage, caesareans, preterm births, and infants with low birth weight.

Danish researchers used population registries for the years 2005 to 2012 to assemble a cohort of pregnancies among women with migraine and a comparison cohort of pregnancies among women without migraine. The findings were published in the journal Headache.

They computed adjusted prevalence ratios (aPRs) for pregnancy and birth outcomes and adjusted risk ratios (aRRs) for neonatal and postnatal outcomes, adjusting for age, preconception medical history, and preconception reproductive history and identified 22,841 pregnancies among women with migraine and 228,324 matched pregnancies among women without migraine.

Median age in both groups was 31; pregnancies among women with migraine had higher preconception prevalences of hypertension, depression, and asthma, while the prevalence of diabetes was comparable in the 2 groups.

The women had been to a hospital as a result of their migraine or had received at least 2 prescriptions for migraine medication.

While about 20% of all births in Denmark are by caesarean section, the study showed that the risk for pregnant women with migraine was 15% to 25% higher than for pregnant women without migraines. The findings indicated that migraine in pregnancy is linked to an increased risk of:

• Pregnancy‐associated hypertension disorders (aPR:1.50; 95% CI, 1.39-1.61)
• Miscarriage (aPR:1.10; 95% CI, 1.05‐1.15)
• Increased prevalence of low birth weight (aPR: 1.14; 95% CI, 1.06‐1.23)
• Preterm birth (aPR: 1.21; 95% CI, 1.13‐1.30)
• Cesarean delivery (aPR: 1.20; 95% CI, 1.15‐1.25)

Children exposed to maternal migraine in utero had elevated risks of:

• Intensive care unit admission (aRR: 1.22; 95% CI: 1.03‐1.45)
• Hospitalization (aRR: 1.12; 95% CI: 1.06‐1.18)
• Dispensed prescriptions (aRR: 1.34; 95% CI: 1.24‐1.45)
• Respiratory distress syndrome (aRR: 1.20; 95% CI: 1.02‐1.42)
• Febrile seizures (aRR: 1.27; 95% CI: 1.03‐1.57)

Researchers have also used the same data to deduce that migraine medication possibly prevents some of the complications. However, the results must be interpreted with caution, the study's lead author said in a statement. "The study was not specifically designed to examine this aspect. However, we show that the risk of complications generally was lower for pregnant women with migraine who took medication when compared with the pregnant women with migraines who were not treated. This also indicates that the migraine medication isn't the cause of the complications, but rather the migraine itself. This is important knowledge for pregnant women with migraines," said Nils Skajaa, BSc.

Migraines are relatively common and affect twice as many women as men. The actual cause remains unknown, but previous research suggests that migraines may be triggered by stress, fatigue, or hormonal changes such as pregnancy.

Reference

Skajaa N, Szépligeti SK, Xue F, et al. Pregnancy, birth, neonatal, and postnatal neurological outcomes after pregnancy with migraine [published onlie May 8, 2019]. Headache. doi: 10.1111/head.13536.