Techniques to improve pregnancy and delivery rates in IVF cycles have focused not only on the embryos transferred, but also the conditions in the uterus at the time of transfer and implantation. Prior studies have shown that embryos secrete human chorionic gonadotropin (hCG) prior to implantation. However, in IVF cycles, the embryos have limited time to secrete hCG before implantation must occur because embryos are placed into the uterus rather than traveling there from the fallopian tubes. Recent studies have shown that the introduction of hCG into the uterus prior to embryo transfer may make the uterus more receptive to implantation. These studies involved day 3 embryos and the investigators are seeking to evaluate the potential benefits of hCG on implantation rates of blastocysts (day 5 or day 6 embryos).

The purpose of this study is to determine whether infusion of human chorionic gonadotropin (hCG) into the uterus immediately prior to embryo transfer results in increased implantation rates.

The entire IVF cycle, fresh or frozen, will be conducted per routine. All laboratory culture conditions will be per routine. In fresh and frozen IVF cycles, an embryo transfer will be performed per routine.

At the time of embryo transfer, participants will be randomly assigned to either the control group or the hCG group. Patients in the hCG group will have a mock embryo transfer with 20µL of transfer media including 500IU of hCG. Patients in the control group will have a mock embryo transfer with 20µL of transfer media.

All post-transfer care and pregnancy monitoring will be identical and per routine protocol.

Inclusion Criteria:

• all patients 43 years old or under undergoing fresh or frozen IVF cycles are eligible to participate

Exclusion Criteria:

• patients greater than 43 years old
• patinets currently participating in any other research studies