Background: Evidences reported the advantageous impact of human chorionic gonadotropin (hCG) in process of embryo implantation via activation of LH/hCG receptors expressed in endometrium.
Objective: The current context investigated whether intramuscular (IM) administration of hCG on the frozen embryo transfer (ET) day would improve the pregnancy outcomes ofintracytoplasmic sperm injection (ICSI) cycles.
Methods: A total of 176 artificially prepared frozen-thawed embryo transfer (FET) cycles were categorized into two equal groups: (A) hCG -treated group (in which intramuscular administration of 10,000 IU hCG on the morning of frozen embryo transfer day was done) and (B) control group (underwent routine FET protocol without hCG intramuscular administration. Our primary outcome was clinical pregnancy rate (CPR) that compared between the two groups, secondary outcomes were ongoing pregnancy and first trimester miscarriage rates.
Results: Basic and clinicalpatient characteristics were matched between groups. In terms of CPR, it was significantly superior in patients received IM hCG prior to frozen embryo transfer (FET) compared to control group (70.5% versus 52.3%, P value = 0.013). Regarding ongoing pregnancy rate (OPR), it was improved significantly in hCG group compared to control group (50% versus 28.4%, P value = 0.003). Miscarriage rates were similar among study groups. Univariate analysis revealed that age at the index ICSI cycle, serum progesterone on pregnancy test day (15 days after FET), number/quality of embryos transferred and hCG injection on the embryo transfer day were significant predictors of clinical pregnancy in frozen-thawed cycles. In the multivariate analysis, the intramuscular administration of hCG remained a significant predictor of clinical pregnancy after FET (adjusted odds ratio (AOR) 2.22; P = 0.014).
Conclusions: Intramuscular hCG administration on the frozen embryo transfer day significantly raise the rates of both clinical & ongoing pregnancy.