Oxytocin antagonists for assisted reproduction

Area of Science:

• Reproductive Medicine and Assisted Reproduction Technologies
• Pharmacology and Drug Efficacy Studies
• Clinical Trial Analysis and Evidence Synthesis

Background:

• Embryo transfer (ET) is critical in in vitro fertilisation (IVF), with endometrial wave-like activity negatively impacting pregnancy.
• Oxytocin antagonists, such as atosiban, barusiban, and nolasiban, are explored to mitigate uterine contractions during ET.
• These medications aim to reduce uterine contractions that may interfere with embryo implantation.

Purpose of the Study:

• To evaluate the effectiveness and safety of oxytocin antagonists administered around the time of embryo transfer (ET) in women undergoing assisted reproduction.
• To synthesize evidence from randomized controlled trials (RCTs) on the impact of oxytocin antagonists on key fertility outcomes.

Main Methods:

• A systematic search of multiple databases (Cochrane Gynaecology and Fertility, CENTRAL, MEDLINE, Embase, etc.) was conducted in March 2021.
• Included were randomized controlled trials (RCTs) comparing oxytocin antagonists to placebo or no intervention in women undergoing ET.
• Primary outcomes were live birth and miscarriage; secondary outcomes included clinical pregnancy and adverse events.

Main Results:

• Intravenous atosiban showed uncertain effects on live birth and miscarriage rates but may increase clinical pregnancy rates (low-certainty evidence).
• Subcutaneous barusiban demonstrated uncertain effects on clinical pregnancy rates, with mild injection site reactions reported (very low-certainty evidence).
• Oral nolasiban did not increase live birth rates but improved clinical pregnancy rates (high-certainty evidence), with uncertain effects on miscarriage.

Conclusions:

• Evidence for intravenous atosiban and subcutaneous barusiban in improving pregnancy outcomes after ET is uncertain due to low-certainty data and limited studies.
• Oral nolasiban appears to enhance clinical pregnancy rates but not live birth rates, necessitating further research on its role and specific patient subgroups.
• Large, well-designed RCTs are required to clarify the precise role of atosiban and barusiban, and to identify women who may benefit from these interventions.