RCOG Definition of Recurrent Pregnancy Loss
The Royal College of Obstetricians and Gynaecologists (RCOG) defines recurrent pregnancy loss as the loss of three or more consecutive pregnancies before 24 weeks of gestation. 1
Key Definitional Points
- RCOG requires three or more consecutive losses before 24 weeks gestation to meet criteria for recurrent pregnancy loss 1, 2, 3
- This definition is more conservative than other international guidelines, which may use two losses as the threshold 2, 3
- The losses must be clinically recognized pregnancies (confirmed by ultrasound or hCG) 4
- Anembryonic pregnancies (blighted ova) are counted toward the diagnosis, as they represent confirmed early pregnancy losses that meet diagnostic criteria 4
Comparison with Other Guidelines
The RCOG definition differs from other major societies:
- American Society for Reproductive Medicine (ASRM) and European Society of Human Reproduction and Embryology (ESHRE) define RPL as two or more losses, making them more inclusive 2, 3, 5
- This definitional variation affects approximately 1-5% of couples depending on which threshold is used 2, 3, 6
- Recent guidelines emphasize the need for research on how these different definitions impact diagnosis, treatment, and prognosis 3
Clinical Implications
- The three-loss threshold means fewer couples qualify for formal RPL workup under RCOG criteria compared to ASRM/ESHRE guidelines 2, 3
- However, many clinicians now consider investigation after two losses in nulliparous women or those with specific risk factors, even if not meeting strict RCOG criteria 3
- The prognosis remains generally good regardless of definition, with 72-82% achieving live birth in subsequent pregnancies with supportive care 3, 6
Important Caveat
While RCOG uses the three-loss definition, clinical judgment should guide when to initiate evaluation—particularly in older women or those with specific risk factors where waiting for a third loss may not be appropriate from a fertility preservation standpoint 2, 6.