Comparison of clinical pregnancy rate.

<p>In the long protocol group, the clinical pregnancy rates of the four age ranges were 52.76%, 44.33%, 36.15% and 13.33%, respectively, which were significantly higher than those in the short protocol group (33.33%, 24.58%, 22.49% and 8.72%, respectively; <i>P</i><0.05). As aged increased, the clinical pregnancy rate in the long protocol group significantly decreased (<i>P</i><0.05). * <i>P</i><0.05 versus the short protocol group.