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NCT Number: NCT07542730

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

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.

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Key information

Conditions

Pain Abortion Anxiety Anxiety Disorders Mental Disorders Neurologic Manifestations Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year and older

Sex eligibility

Female

Study type

Interventional

Phase

Phase 4

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Adults age 18 years and older
  • Desire procedural abortion with moderate sedation
  • Gestational age less than or equal to 13 weeks
  • Intrauterine pregnancy or pregnancy of unknown location
  • Body mass index less than or equal to 40

Exclusion criteria

  • Desire medical abortion or desire to continue pregnancy
  • Gestational age greater than 13 weeks
  • Body mass index greater than 40
  • Age younger than 18 years
  • Confirmed ectopic pregnancy
  • Medical condition that is a contraindication to moderate sedation as determined by the treating clinician

Treatment and study plan

diphenhydramine

Drug

Diphenhydramine 50 mg administered intravenously once prior to the procedure.

Other names: Bendaryl

Placebo

Drug

Matching placebo composed of normal saline administered intravenously once prior to the procedure.

Primary outcomes

  1. Participant-Reported Pain During Uterine Aspiration

    Time frame: During the procedure, at the time of 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.

Secondary outcomes

  1. Sedation Depth During Uterine Aspiration

    Time frame: During the procedure, at the time of 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.

  2. Participant-Reported Pain at Speculum Placement

    Time frame: During the procedure, at the time of 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.

  3. Participant-Reported Pain at Paracervical Block

    Time frame: During the procedure, at the time of 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.

  4. Participant-Reported Pain at Cervical Dilation

    Time frame: During the procedure, at the time of 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.

  5. Participant-Reported Pain 10 Minutes After Procedure Completion

    Time frame: 10 minutes after completion of the procedure

    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.

  6. Participant-Reported Pain 1 Hour After Procedure Completion

    Time frame: 1 hour after completion of the procedure

    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.

  7. Time to Readiness for Discharge

    Time frame: From completion of the procedure until discharge readiness, up to approximately 2 hours

    Time from procedure completion to when the participant meets discharge criteria, measured in minutes. Higher values indicate longer recovery time.

  8. Incidence of Sedation-Related Adverse Events

    Time frame: From administration of study medication through discharge on the day of procedure

    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.

Study contacts

Contact information is provided by the study sponsor or research team.

Sarah Cavegila, MPH

CONTACT

[email protected]

585-273-5734

Sponsors and collaborators

Lead sponsor

University of Rochester

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Apr 21, 2026
Registry last updated
Apr 21, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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