This single center, double blind, randomized controlled trial will evaluate whether adding intravenous diphenhydramine to a standard moderate sedation regimen improves pain control during first trimester procedural abortion. Participants undergoing uterine aspiration at less than 13 weeks gestation will be randomized 1 to 1 to receive standard moderate sedation with midazolam and fentanyl plus either diphenhydramine 50 mg intravenously or matching placebo. The primary outcome is participant reported pain during uterine aspiration measured by a 100 mm Visual Analog Scale.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
QUADRUPLE
Enrollment
98
Diphenhydramine 50 mg administered intravenously once prior to the procedure.
Matching placebo composed of normal saline administered intravenously once prior to the procedure.
Gender Wellness OB/GYN
Rochester, New York, United States
RECRUITINGParticipant-Reported Pain During Uterine Aspiration
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS). The VAS ranges from 0 to 100 mm, where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures the participant's perceived pain during uterine aspiration.
Time frame: During the procedure, at the time of uterine aspiration
Sedation Depth During Uterine Aspiration
Sedation depth will be assessed using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale. The MOAA/S scale ranges from 0 to 5, where 5 indicates fully alert and 0 indicates no response to painful stimulus. Lower scores indicate deeper levels of sedation. This outcome measures the level of sedation achieved during uterine aspiration.
Time frame: During the procedure, at the time of uterine aspiration
Participant-Reported Pain at Speculum Placement
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS), where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures pain experienced during speculum placement.
Time frame: During the procedure, at the time of speculum placement
Participant-Reported Pain at Paracervical Block
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS), where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures pain experienced during administration of the paracervical block.
Time frame: During the procedure, at the time of Paracervical Block
Participant-Reported Pain at Cervical Dilation
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS), where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures pain experienced during cervical dilation.
Time frame: During the procedure, at the time of Cervical Dilation
Participant-Reported Pain 10 Minutes After Procedure Completion
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS), where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures post-procedure pain at 10 minutes.
Time frame: 10 minutes after completion of the procedure
Participant-Reported Pain 1 Hour After Procedure Completion
Pain intensity will be measured using a 100 mm Visual Analog Scale (VAS), where 0 represents "no pain" and 100 represents "worst pain imaginable." Higher scores indicate greater pain intensity. This outcome measures post-procedure pain at 1 hour.
Time frame: 1 hour after completion of the procedure
Time to Readiness for Discharge
Time from procedure completion to when the participant meets discharge criteria, measured in minutes. Higher values indicate longer recovery time.
Time frame: From completion of the procedure until discharge readiness, up to approximately 2 hours
Incidence of Sedation-Related Adverse Events
Number and proportion of participants experiencing sedation-related adverse events, including hypoxia, hypotension, use of reversal agents (naloxone or flumazenil), paradoxical agitation, respiratory depression requiring supplemental oxygen beyond nasal cannula, hypotension requiring vasopressors, or unplanned hospital admission. Higher values indicate greater incidence of adverse events.
Time frame: From administration of study medication through discharge on the day of procedure
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