Fig. 1From: Decrease in preovulatory serum estradiol is a valuable marker for predicting premature ovulation in natural/unstimulated in vitro fertilization cycleReceiver operation curve (ROC) analyses of premature E2/−1E2 ratios in the unstimulated IVF cycles (A) and in the cycles with premature LH surge (B). The cut-off value was 0.84 for premature E2/−1E2 ratios in unstimulated IVF cycles and 0.77 for premature E2/−1E2 ratios in cycles with premature LH surgeBack to article page