Table 1.

Excluded studies from systematic review based on the full text

Reasons	Studies excluded
Analysis did not take into account the complete range of E2 levels available	Sharara and McClamrock 1999, Friedler et al. 2005, Bahçeci et al. 2006, Chen et al. 2007, Yoldemir and Fraser 2009, Moraloglu et al. 2012
No extractable data	Blazar et al. 2004, Papageorgiou et al. 2002
Inclusion of serum E2 levels in the hCG administration criteria	Mettler et al. 1989, Chenette et al. 1990, Dor et al. 1992, Gelety and Buyalos 1995, Simon et al. 1995