Diphenhydramine as an Adjunct to Moderate Sedation for Procedural First Trimester Abortions

Surgical abortion is commonly associated with pain and anxiety despite use of local anesthesia and moderate sedation. This study will evaluate the efficacy of intravenous diphenhydramine as an adjunct to a standard moderate sedation regimen for participants undergoing first trimester procedural abortion. This is a single center, double blind, randomized, placebo controlled trial conducted at the University of Rochester Family Planning Clinic and Strong Memorial Hospital. Participants undergoing first trimester uterine aspiration at less than or equal to 13 weeks gestation will be randomized in a 1 to 1 ratio using a computer generated block randomization scheme to receive either intravenous diphenhydramine 50 mg or matching placebo, in addition to standard moderate sedation with midazolam and fentanyl. Participants, clinical staff, and outcome assessors will remain blinded to treatment assignment. Pain will be assessed using a 100 mm Visual Analog Scale at baseline, during speculum placement, paracervical block, cervical dilation, uterine aspiration, 10 minutes after the procedure, and 1 hour after the procedure. Sedation depth during uterine aspiration will be assessed using the Modified Observer's Assessment of Alertness Sedation scale. Additional outcomes include total sedative medication dose, time to readiness for discharge, and sedation related adverse events.