Occipital nerve block versus acetaminophen/ caffeine for headache treatment in pregnancy: a randomized trial

To evaluate the efficacy of occipital nerve block (ONB) compared to standard care (SC) for treatment of acute headache (HA) in pregnancy. Single-center randomized controlled trial of pregnant patients with HA and pain score >3 on the verbal rating scale (VRS). Patients with secondary HA, preeclampsia, >3g of acetaminophen within 24 hours, ONB within 3 months, and/or allergy to study medications were excluded. Participants were randomized 1:1 in variable block sizes to bilateral ONB with 5cc of 5% bupivacaine or SC (oral 650mg acetaminophen/200mg caffeine). Crossover treatment was given at 2 hrs and 2nd-line treatment (oral 25mg promethazine/diphenhydramine) at 4 hrs to those with worsening VRS or VRS >3. The primary outcome was HA resolution or improvement to VRS ≤3 2 hrs after initial therapy. Secondary outcomes included serial VRS scores, receipt of crossover or 2nd-line therapy, patient satisfaction, and perinatal outcomes. Outcomes were assessed in an intention-to-treat analysis. We estimated a sample of n=62 would afford 80% power to detect a difference from 85% to 50% between groups. From 2/2020-5/2022, 62 participants were randomized to ONB (n=31) or SC (n=31). Groups were similar except payor status (Table 1). The primary outcome was higher in the ONB group, albeit nonsignificant (64.5 vs 51.6%, p=0.30) (Table 2). However, the ONB group had faster improvement of HA at 1 hr (VRS 2 [IQR 0-5] vs 6 [IQR 2-7], p=0.014) and more ONB patients had VRS score ≤3 at 1 hr. This resulted in 18 patients (58%) leaving triage within 2 hrs of ONB due to HA resolution versus 11 (35%) receiving SC. Among remaining participants, the SC group had significantly lower VRS score at 1 hr following crossover to ONB than the ONB group receiving crossover to SC (p=0.028). There were no significant differences in 2nd-line treatment, refractory HA, satisfaction, or complications. Patients receiving ONB delivered earlier (36.6 vs 37.8 wks), but preterm birth did not differ between groups (Table 2). ONB appears to be a promising and quick-acting treatment option for acute HA in pregnancy.View Large Image Figure ViewerDownload Hi-res image Download (PPT)