Number of oocytes and IVF outcomes: Real-world evidence

Randomized controlled trials (RCTs) are gold standard to study the effect of an intervention and establish causation between the treatment and outcomes. However, RCTs have the disadvantage of being expensive, entailing high resource investments and involving only selected patient populations under experimental settings. Real-world evidence (RWE) from real-world data (RWD) involves a heterogenous patient population in real-world settings. RWE is less expensive and quicker than RCTs; it can provide complimentary evidence if methodological challenges, such as residual confounding and susceptibility to bias, are considered when interpreting the findings. This review examines RWE regarding the association between the number of oocytes following ovarian stimulation and IVF outcomes into shaping current IVF practices.