Migraine and risk of adverse obstetric outcomes: a matched cohort study of English linked electronic health records.

BACKGROUND

Existing literature suggests a link between migraine and various adverse pregnancy outcomes, but findings remain inconsistent. This study aimed to evaluate the association between pre-pregnancy migraine and obstetric outcomes.

METHODS

This retrospective cohort study used linked electronic health records from Clinical Practice Research Datalink (CPRD) GOLD and Hospital Episode Statistics (HES) maternity data. We included women aged 15-50 years in England with singleton deliveries between 2000 and 2019. Deliveries from women with a recorded migraine diagnosis before pregnancy were matched 1:1 by maternal age to those without migraine. Logistic regression models, adjusted for demographic and clinical factors, were used to examine associations with preterm birth, low birth weight, small for gestational age (SGA), mode of delivery, and stillbirth.

RESULTS

The cohort included 428,217 deliveries from 317,016 women, comprising 46,560 (10.9%) migraine-exposed deliveries and an equal number of matched controls. No significant association was found between pre-pregnancy migraine and preterm birth (aOR 1.04(0.99-1.09)), although migraine appeared to have a protective effect against very preterm birth (aOR 0.83(0.73-0.95)). Pre-pregnancy migraine was associated with increased odds of iatrogenic preterm birth (aOR 1.10, 95% CI: 1.04-1.18), but not spontaneous preterm birth (aOR 0.97, 95% CI: 0.91-1.03). Migraine was associated with a significant increase in the odds of pre-eclampsia (aOR 1.17 (95% CI 1.07-1.27)). There were no notable associations with low birth weight (1500-2500 g) (aOR 1.02, 95% CI: 0.95-1.09), very low (1000-1500 g) or extremely low birth weight (< 1000 g), SGA (aOR 0.96, 95% CI: 0.89-1.03), or stillbirth (aOR 1.00, 95% CI: 0.81-1.24). No significant association was seen between migraine and elective caesarean section (aOR 1.04, 95% CI: 0.99-1.09).

CONCLUSION

Pre-pregnancy migraine was associated with increased odds of iatrogenic preterm birth and pre-eclampsia. Associations with other outcomes were small and uncertain. Further research is needed to understand the mechanisms underlying these findings and their clinical relevance.