This study aims to evaluate whether allowing unprotected vaginal intercourse 24 hours after frozen embryo transfer will result in higher ongoing clinical pregnancy rates in comparison to having participants abstain from unprotected vaginal intercourse until pregnancy test (10-14 days after frozen embryo transfer).

Given the overwhelming evidence suggesting beneficial effect of seminal plasma on embryo implantation, we sought to explore this benefits in in vitro fertilization treatments by limiting the study cohort to those having frozen embryo transfer with programmed hormone replacement for endometrial preparation and some form of parenteral progesterone supplementation. This design will enable us to overcome the concerns and limitations of all previous studies. In this study, patients will be randomized into two groups, group 1 will have their frozen embryo transfer followed by current standard of care (no unprotected vaginal intercourse until pregnancy test) and group 2 will have their frozen embryo transfer followed by unlimited unprotected vaginal intercourse starting 24 hours after transfer. The primary endpoint of the study will be ongoing clinical pregnancy

rates in the two groups while secondary endpoints will include implantation, positive pregnancy, miscarriage and live birth rates. Overall, this study aims to investigate whether the elimination of current universal pelvic rest protocol in patients undergoing frozen embryo transfer will help optimize pregnancy outcomes.

This study aims to evaluate whether allowing unprotected vaginal intercourse 24 hours after frozen embryo transfer will result in higher ongoing clinical pregnancy rates in comparison to having participants abstain from unprotected vaginal intercourse until pregnancy test (10-14 days after frozen embryo transfer).

Inclusion Criteria:

• female fertility patients having frozen embryo transfer
• programmed hormone replacement (Oral Estrace, Vivelle dot (patch), intravenous Estradiol) with and without gonadotrophin releasing hormone analogue pretreatment and some form of parenteral progesterone supplementation (daily or every 3 days intramuscular Progesterone) for luteal support

Exclusion Criteria:

• unable to provide informed consent
• not undergoing programmed hormone replacement for frozen embryo transfer (natural cycle frozen embryo transfer)
• undergoing fresh embryo transfer
• not able to engage in heterosexual intercourse (same sex couple, partner with severe sexual dysfunction)
• cannot undergo unprotected vaginal intercourse (infected with hepatitis B, C, or human immunodeficiency virus).

Only patients undergoing embryo transfer will be candidates for the study.

After informed consent signing and randomization using a computer generated randomization scheme, the Research Nurse will open a numbered, opaque, and sealed envelope, within which there will be a white sheet of paper labelled with the patient assigned group. The participant will be informed of their assigned group by the Research Nurse. Patients assigned to the study group will be handed a log to record the number of times the patient engages in unprotected vaginal intercourse. The fertility providers will be blinded to the patients assigned treatment group. Patients who do not consent to be part of the study will still undergo their planned frozen embryo transfer per protocol.