The Impact of migraine on fertility and family planning in the Nationwide Swedish Health Care Registry.

Abstract

Objectives/background: Our objective was to determine the impact of migraine on women's fertility and birth planning. Migraine preferentially affects women of childbearing age, and previous studies have suggested that migraine negatively affects a woman's decision to have children. We used the Swedish National Registry to determine the impact of migraine on women's fertility patterns including overall likelihood of childbirth, number of children, age at first birth, and birthing outcomes.

Methods: Our study used a retrospective matched cohort design including all women born in Sweden between 1973 and 1996 who were registered in the Swedish Medical Birth Register and resided in Sweden as of 2018. Cases comprised women in the National Patient Register diagnosed with migraine between 2001 and 2018. Each case was matched by birth year to two controls without a recorded migraine diagnosis. We first assessed partum outcomes including number of children, age at first birth, length of gestation, and interval between first and second pregnancy. We then analyzed postpartum outcomes including birth weight less than 2500 g, preterm delivery before 37 weeks, Apgar score less than 7 at 5 min, postpartum depression, and preeclampsia.

Results: Our inclusion criteria yielded a cohort of 49,318 women with migraine and 98,636 women without, of whom 37,455 had data in the birth register: 7198 with a diagnosis of migraine before pregnancy (MBP), 6575 with migraine after pregnancy (MAP), and 23,682 with no diagnosis of migraine. Overall, women with any diagnosis of migraine in the study window had an increased likelihood of having any births relative to women without migraine (adjusted odds ratio = 1.21, 95% confidence interval [CI] = 1.18-1.24; p < 0.001) and had 0.072 more children (95% CI = 0.063-0.081; p < 0.001). However, when stratified by whether the diagnosis of migraine occurred before or after pregnancy, women with MBP had 0.23 fewer children (95% CI = -0.24 to -0.21; p < 0.001), whereas those with MAP had 0.33 more children (95% CI = +0.30 to +0.35; p < 0.001). Similarly, women with MBP were older than controls (+0.52 years, 95% CI = +0.40 to +0.63; p < 0.001), whereas those with MAP were younger by 1.65 years (95% CI = -1.77 to -1.53; p < 0.001). Women with MBP waited less time between pregnancies (-0.69 years, 95% CI = -0.74 to -0.64; p < 0.001), whereas those with MAP waited longer (+0.82, 95% CI = +0.74 to +0.90; p < 0.001). Preterm deliveries were increased only in MBP with aura. Vaginal deliveries only decreased in those with MAP, whereas postpartum depression was increased in those with both MBP and MAP. Preeclampsia was increased in those with MBP only.

Conclusion: Our study suggests that women in Sweden with MBP delay having children, have fewer children, and are at an older age than women without migraine, but may wait less time between pregnancies. Our study further confirms the increased risk of preeclampsia and postpartum depression in mothers with migraine as well as preterm delivery in infants born to mothers with migraine with aura.