Efficacy and safety of greater occipital and related peripheral nerve blocks for migraine in pregnancy: a systematic review

Migraine treatment during pregnancy is constrained by concerns about fetal exposure to systemic medications. Occipital nerve block is a non-systemic option, but pregnancy-specific evidence remains limited. To systematically evaluate the efficacy and safety of greater occipital and related peripheral nerve blocks for migraine or acute primary headache during pregnancy. This review followed PRISMA 2020 and was prospectively registered in PROSPERO (CRD420251170192). MEDLINE, Embase, CINAHL, Scopus, Cochrane CENTRAL, and Google Scholar were searched from inception to December 2025. Randomized and non-randomized studies reporting pregnancy-specific efficacy or safety outcomes after occipital or related cranial peripheral nerve blocks were eligible. Risk of bias was assessed using RoB 2 and ROBINS-I, and findings were synthesized narratively. Four studies published from 2014 to 2025 were included: one randomized controlled trial, two retrospective cohorts, and one retrospective case series. Across these studies, 177 pregnant participants were enrolled, of whom 78 initially received a nerve-block intervention; additional crossover exposure in the randomized trial was not included in this count. The randomized trial did not show a statistically significant difference in its primary two-hour outcome, although pain scores were lower at one hour with occipital nerve block. Small uncontrolled studies reported reductions in pain after treatment. No serious immediate procedure-related maternal adverse events were reported among exposed participants, but obstetric and neonatal outcomes were incompletely reported, and the studies were not powered to detect uncommon harms. Limited, low-certainty evidence suggests that occipital and related peripheral nerve blocks may provide rapid migraine or headache relief during pregnancy. The available evidence is insufficient to establish comparative efficacy or rule out uncommon maternal, obstetric, or neonatal harms.