Main findings
In the present study, we found that the ongoing pregnancy rate was similar in the PPOS group and the antagonist group. In order to control for the differences in the demographic and index stimulation cycle characteristics, a multivariate logistic regression was performed and indicated the stimulation protocol was one of the factors predicting the ongoing pregnancy rate of IVF. Our results were in agreement with that of a previous study 12which showed lower pregnancy rates in recipients of oocytes from the MPA group compared to that from the antagonist group.