Mild ovarian stimulation for in vitro fertilization: are we ready to change? A meta-analysis.

Objective: To compare the efficacy of mild ovarian stimulation versus conventional stimulation in in vitro fertilization (IVF).

Design: Meta-analysis.

Search Strategy: A systemic literature search was carried out for prospective randomised clinical trials. We electronically searched using PubMed, Medline and Embase for all the studies published from 1990 to December 2011.

Interventions: Mild ovarian stimulation IVF that uses lower doses and/or shorter duration of gonadotrophins in GnRH antagonist co-treated cycle compared with conventional stimulation IVF.

Main Outcome Measures: Live birth rates per started cycle and ongoing pregnancy rates per started cycle of IVF.

Results: On live birth rate, there was a significant difference in favour of the conventional stimulation [70/444 (15.7%) mild vs. 78/325 (24%) conventional] (OR 0.59, CI 0.41-0.85, p = 0.004). Similar findings were observed in the ongoing pregnancy data [140/696 (20%) mild vs. 144/547 (26%) in favour of conventional stimulation] (OR 0.72, CI 0.55-0.93, p = 0.01). The sub-analysis of two studies showed a statistically significant reduction of hyperstimulation syndrome in favour of the mild stimulation (OR 0.27, CI 0.11-0.66).

Conclusion: This analysis presents strong evidence in favour of conventional stimulation IVF, which therefore should currently be considered a treatment of choice for patients requiring IVF treatment.