The process of in vitro fertilization (IVF) culminates in the embryo transfer (ET), where a developed embryo is placed directly into the uterus. This procedure marks a highly anticipated moment for couples, often leading to questions about activities that might affect its success. A common concern is whether sexual activity in the days leading up to the transfer should be avoided. The decision regarding intercourse before ET has been a subject of debate, with both theoretical risks and potential benefits discussed in the medical literature.
Understanding the Theoretical Risks
The anxiety surrounding sexual activity before an embryo transfer stems from two main theoretical biological concerns: uterine contractility and the components of seminal fluid. Sexual arousal and orgasm can induce myometrial contractions, which are the muscular movements of the uterus. The theory suggests that these contractions could potentially disrupt the delicate environment of the uterine lining or physically interfere with the successful placement or retention of the embryo after the procedure.
The concern regarding intercourse centers on the possibility of a hyperactive uterine environment just before the transfer. Although contractions are a natural physiological response, some worry that increased uterine motion could negatively impact the process of establishing a pregnancy. This mechanical disturbance is one reason why many clinics traditionally advised against intercourse close to the transfer date.
Seminal fluid introduces risk due to its composition, which includes prostaglandins. These hormone-like compounds are known to cause smooth muscle contraction, including the muscles of the uterus. While prostaglandins play a role in preparing the immune environment of the uterus for pregnancy, their potential to induce contractions is a source of caution.
The introduction of seminal fluid could also theoretically increase the risk of infection, as the transfer procedure involves passing a catheter through the cervix. An infection could create a hostile environment for the embryo. These potential biological mechanisms are the foundation for clinical recommendations that often err on the side of caution.
Clinical Evidence and Pre-Transfer Recommendations
The clinical evidence surrounding sexual activity before embryo transfer is complex and lacks a single, clear recommendation. Some studies found no significant difference in pregnancy rates between patients who had intercourse and those who abstained before the transfer. This suggests that the theoretical risks of uterine contractions or infection may not translate into a negative clinical impact on success rates.
Other research has suggested a potential benefit, particularly from exposure to seminal fluid. Seminal plasma contains immunomodulatory factors that may help the reproductive tract become more receptive to the embryo, a process called immunological priming. A meta-analysis involving thousands of patients indicated that women exposed to semen around the time of IVF saw a statistically significant increase in the clinical pregnancy rate, estimated at around 23%.
A randomized controlled trial focusing on frozen embryo transfers (FET) found that patients who had protected intercourse the night before demonstrated higher clinical pregnancy and implantation rates compared to those who abstained. Since this study used barrier contraception, it suggests the physical component of the sexual act, potentially through increased blood flow, might be beneficial independent of seminal fluid exposure.
Despite evidence suggesting a neutral or positive effect, current guidance from fertility clinics remains varied and conservative. Many specialists recommend refraining from intercourse for a short period, typically 24 to 48 hours immediately preceding the embryo transfer. This short abstinence minimizes the risk of introducing bacteria and helps ensure the uterus is relaxed. Patients may be advised to follow a longer abstinence period, sometimes 2 to 7 days, depending on the clinic’s protocol.
Sexual Activity Following Embryo Transfer
The question of sexual activity changes once the embryo transfer is complete, moving into the two-week waiting period. Post-transfer concerns shift from preparing the uterine environment to minimizing disruption to the implantation process. Most fertility specialists advise avoiding intercourse for a defined period after the procedure, commonly five to seven days, covering the typical window for embryo implantation.
The main reason for this post-transfer recommendation is the theoretical risk of uterine contractions induced by orgasm, which could hinder the embryo’s ability to attach to the uterine lining. Additionally, the cervix may be slightly open following the transfer, leading to a theoretical risk of introducing infection through intercourse. While definitive evidence linking post-transfer sex to lower pregnancy rates is lacking, medical advice errs on the side of caution during this sensitive time.
This period of required abstinence can sometimes increase psychological distress for couples navigating the emotional challenges of IVF treatment. Intimacy is a source of connection and stress reduction, and completely eliminating it can be challenging. Couples are encouraged to find alternative ways to maintain emotional and physical closeness without full intercourse during this waiting period. Ultimately, patients should adhere to the specific instructions provided by their fertility clinic.