Summary: Miscarriage is defined as the spontaneous loss of pregnancy before the fetus reaches viability. The term therefore includes all pregnancy losses from the time of conception until 24 weeks of gestation. It should be noted that advances in neonatal care have resulted in a small number of babies surviving birth before 24 weeks of gestation.
Recurrent miscarriage, defined as the loss of three or more consecutive pregnancies, affects 1% of couples trying to conceive. It has been estimated that 1–2% of second-trimester pregnancies miscarry before 24 weeks of gestation.
The purpose of this guideline is to review the literature and provide guidance on the investigation and treatment of couples with recurrent miscarriage.
COVID disclaimer: This guideline was developed as part of the regular updates to programme of Green-top Guidelines, as outlined in our document Developing a Green-top Guideline: Guidance for developers, and prior to the emergence of COVID-19.
Version history: This is the third edition of this guideline; the fourth edition is currently in development.
Developer declaration of interests: Available on request.