Objective:: To compare die effect of two different limes of ousel of lutcal phase support on ongoing pregnancy rale in
infertile patients undergoing treatment with GnRH down-regulated IVF and embryo transfer (IVF/ET).
Design: prospective randomized trial.
Setting : Assisted reproductive tecbnology program at the shatby university hospital for women , and Madina infertility
Private center in Alexandria.
Patients : one hundred and forty patients undergoing IVF-ICSI program.
Intervention: All palicnls planned to undergo Iheir first IVF treatment cycle were randomly allocated lo receive
parentral progesterone as luteal support at two different lime points, that is, the clay before embryo transfer (ET) and til
the day of ET. The primary endpoint of ibis study was ongoing pregnancy rale.
Main outcome Measures: Clinical pregnancy rates.
Results : A total of 140 women were randomized; 70 were allocated lo the day before embryo transfer group , and 70 lo
the group of the day of ET. An ongoing pregnancy rate was 22.7% in the day before embryo transfer group versus
23.6% at the day ET group, respectively.
Conclusion : We could not identify, within the chosen time points and within the sample size, a specific implantation
window period in which an optimal endometrial receptivity yields the highest pregnancy rate.