Comparison of daily vaginal progesterone gel plus weekly intramuscular progesterone with daily intramuscular progesterone for luteal phase support in single, autologous euploid frozen-thawed embryo transfers

Purpose To compare outcomes between daily intramuscular progesterone (IMP) and daily vaginal progesterone (VP) gel plus weekly intramuscular hydroxyprogesterone caproate (IMHPC) for luteal phase support (LPS) in single, autologous euploid frozen-thawed blastocyst transfers (FBTs) following artificial endometrial preparation (EP). Methods The retrospective cohort study included 767 single, autologous FBTs from 731 patients between January 2015 and March 2018. LPS was performed either with IMP (100 mg/day) or with VP gel (90 mg, twice daily) plus IMHPC (250 mg/week). Oral estrogen was prescribed in combination of both regimes. Oral estrogen was discontinued following the visualization of fetal cardiac activity on ultrasound and progesterone at 10 weeks of gestation. The primary outcome was live birth rate. The secondary outcomes included implantation, clinical pregnancy, and multiple pregnancy rates. Results Patient characteristics did not differ in LPS regimes. Of 767 FBTs, 608 had IMP (100 mg/day) for LPS and 159 had VP gel (90 mg, twice daily) plus IMHPC (250 mg/week) for LPS. The live birth rate was 51.8% and 50.3%, respectively (p = 0.737, OR 0.94, 95%CI 0.66-1.33). The implantation rate was 62.7% and 64.2%, respectively (p = 0.730, OR 1.06, 95%CI 0.74-1.53). The clinical pregnancy rates were also similar in both groups (59.5% vs. 61.6%, respectively, p = 0.631, OR 1.09, 95%CI 0.76-1.56). Conclusions We did not observe significant differences in the rates of live birth, implantation, and clinical pregnancy between daily IMP and daily VP gel plus weekly IMHPC for LPS in single, autologous euploid FBTs after artificial EP.