The aim of this study was to compare the effects of starting progesterone (P4) luteal support (LS) on day of egg retrieval (ER) or day of embryo transfer (ET) on the ratio of difficult ET and cycle outcome. This was a RCT ( ClinicalTrials.gov Identifier: NCT03040830) carried out at Mansoura Integrated Fertility Center (MIFC), Mansoura, Egypt, from November 2015 to January 2017. A total of 171 eligible long agonist ICSI cases were randomly allocated on day of ER into group A (86) starting LS as daily IM 100 mg P4 on day of ER and group B (85) starting P4-LS on day of ET. Difficult ET was defined as blood on ET catheter and/or sounding or dilating the cervix. Primary outcome was the overall ratio of difficult ET and ratios on day 3 and 5 ET. Secondary outcome was the ongoing pregnancy rate (OPR) and implantation rate (IR). The results are presented as % for groups A and B respectively: overall difficult ET (44.1, 24.7) (p = 0.009); day 3 difficult ET (23.2, 24.4) (p = 0.45); day 5 difficult ET (62.7, 25.6) (p = 0.001); overall OPR (38.3, 44.7) (p = 0.43); day 3 ET OPR (41.8, 33.3) (p = 0.51); day 5 ET OPR (34.8, 57.5) (p = 0.048); overall IR (20.0, 22.5) (p = 0.62); day 3 ET IR (17.8, 13.4) (p = 0.44); day 5 ET IR (22, 34.1) (p = 0.09). In conclusion, starting P4 luteal support on egg retrieval day is associated with significantly higher ratio of difficult embryo transfer and lower ongoing pregnancy rate and tendency to lower IR in day 5 ET, so starting P4-LS on day of ET is recommended.
Keywords: Embryo transfer; Luteal support; Progesterone.