Local anaesthesia for pain control in surgical abortion before 14 weeks of pregnancy: a systematic review

Abortions are common and associated with procedural pain. We aimed to evaluate benefits and harms of local anaesthesia given for pain control during surgical abortion at less than 14 weeks' gestation.

We searched a systematic review on local anaesthesia for pain control for surgical abortion at less than 14 weeks' gestation using uterine aspiration. We searched multiple databases through December 2022. We evaluated study quality using the Cochrane Risk of Bias 2 (RoB2) instrument and assessed the certainty of evidence using GRADE (Grading of Recommendations Assessment, Development and Evaluation). Outcomes included intraoperative pain (with dilation, aspiration or procedure), patient satisfaction and adverse events.

Thirteen studies with 1992 participants met the inclusion criteria and the majority were judged as low risk of bias. Intervention protocols were heterogeneous, limiting meta-analysis. A 20 mL 1% lidocaine paracervical block (PCB) reduced pain with dilation compared with sham PCB (mean difference (MD) -37.00, 95% CI -45.64 to -28.36) and aspiration (MD -26.00, 95% CI -33.48 to -18.52; 1 randomised controlled trial (RCT), n=120; high-certainty evidence). A PCB with 14 mL 1% chloroprocaine was associated with a slight reduction in pain during aspiration compared with normal saline PCB injected at two or four sites (MD -1.50, 95% CI -2.45 to -0.55; 1 RCT, n=79; high-certainty evidence). Other RCTs compared a range of local anaesthetic types, PCB techniques and topical anaesthetics. Participants reported moderately high satisfaction with any type of pain control and studies reported few adverse events that were rarely medication-related.

RCT evidence supports PCB efficacy but was inconsistent and of low certainty for topical anaesthesia.