Human chorionic gonadotropin (hCG) is important in preparing the endometrium for optimal embryo implantation. However, clinical application of hCG in prior to embryo transfer has been controversial. We evaluated the efficacy of the systemic or local administration of hCG for frozen-thawed embryos transfer in hormone replacement (HR) cycles.
Prospective randomized trials
【Materials and Methods】
Study1: Systemic administration
A total of 173 patients who received frozen-thawed embryo transfer during HR cycle were initially randomized into two groups. In the study group (n=86), 3000 IU hCG was injected intramuscularly days 17, 20, and 23 of the cycles, in addition to estradiol and progesterone. Patients in the control group (n=87) were not given hCG.
Study 2: Local administration (intrauterine hCG injection before embryo transfer)
A total of 198 patients who received single frozen-thawed blastocyst transfer during HR cycles were randomized into two groups. The study group (n=99) received an intrauterine injection of 100 μl cultured medium containing 1000 IU of hCG. In the control group (n=99), patients were given only 100 μl intrauterine culture medium. In both groups, intrauterine injections were performed 3 days before blastocyst transfer using an embryo transfer (ET) catheter.
The primary outcome measure was the clinical pregnancy rate (CPR). The secondary outcome measure was the miscarriage rate.The study procedures were approved by the Institutional Review Board of Hanabusa Women’s Clinic.
No significant differences were found in the baseline characteristics between the two groups in both studies. In study 1, the CPR per ET and the miscarriage rate of the study group were 44% and 13%, while those of the control group were 46% and 15%, with no statistically significant difference. In study 2, the clinical pregnancy and miscarriage rates were 39% and 13%, while those of the control group were 40% and 13%, respectively with no statistically significant difference.
In study 1, systemic administration of 3000IU hCG did not affect on CPR compared with that of control group. In study 2, we used different dosage of hCG from previous studies (1000 IU in this study, and 500 IU in previous studies). However, in spite of two times higher dosage of hCG application, we could not demonstrate any efficacy of hCG on CPR. Therefore, we suggested that neither systemic nor intrauterine administration of hCG were beneficial for frozen-thawed ET in HR cycles. Further investigations will be required to clarify the role of hCG in such treatments.