Hyoscine butylbromide in pain reduction associated with ultrasound-guided manual vacuum aspiration: a randomized placebo-controlled trial

•Ultrasound-guided manual vacuum aspiration causes painful uterine contraction.•Abdominal pain during USG-MVA is insignificantly reduced by hyoscine butylbromide.•Alternative anti-spasmodics or higher dosage should be investigated. What is the effect of adding an anti-spasmodic drug to an existing ultrasound-guided manual vacuum aspiration (USG-MVA) protocol to alleviate immediate post-procedure abdominal cramping pain in women treated for early pregnancy loss? Double-blind, placebo-controlled, randomized controlled trial conducted between February 2018 and January 2020. Participants were assigned to receive a 1-ml intravenous injection containing 20-mg hyoscine butylbromide (HBB) (n=55) or saline (n =56) as a control immediately before USG-MVA. Primary outcome was reduced abdominal pain after adding a 20-mg dose of HBB to the current pain control regimen. Secondary outcomes were vaginal pain, complications and side-effects, women's pre- and post-procedure psychological state, physiological stress (saliva alpha-amylase) and procedure pain control satisfaction. Two-way mixed ANOVA was used to evaluate the main effects and interactions. VAS abdominal pain scores in the HBB group were 16% lower immediately after and 21% lower 2 h after surgery (not statistically significant). Two-way ANOVA indicated that time (F[1108] = 83.41, P < 0.001) was the only significant main effect for reduced abdominal pain after the procedure and vaginal pain score (F[1108] = 180.1, P < 0.0001) but not drug received. No adverse events were reported. No significant difference was found for psychological state, physiological stress and procedure pain control satisfaction between the two groups. Anti-spasmodic drugs can help to reduce abdominal cramping pain associated with USG-MVA; HBB produced an insignificant decrease in abdominal pain score. Further studies with longer acting or larger doses of anti-spasmodic drugs are warranted.