Addition of Leukemia Inhibitory Factor (LIF) Could Benefit Clinical in Vitro Fertilization Culture

Objective: This study aimed to assess whether the addition of LIF (leukemia inhibitory factor) into a specific culture medium will increase the embryo quality susceptible to enhance pregnancy rate following embryo transfer. Methods: This is a blind prospective study, conducted on 2,192 oocytes received the day of ovum pick-up from 326 women undergoing the ICSI program. In each microdroplet of embryo culture medium containing an oocyte microinjected, LIF was randomly added on day 0 or on day 1 after the microinjection, and the microinjected oocytes were incubated individually. The embryo quality on day 2 and day 3 (blastomere number, blastomere regularity and fragmentation rate) was compared. Results: The number of four-cell embryos (on day 2), eight-cell embryos (on day 3) and embryos with regular blastomeres in both days were higher with LIF. The adjunction of LIF just after the microinjection provided better results than 24 hours after the microinjection. A statistically significant improvement was observed in embryos with a low fragmentation rate on both days 2 and 3. LIF also seems to improve pregnancy, implantation and live birth rates, but with no significant difference. Conclusion: Addition of LIF to embryo culture media after ICSI program has a beneficial effect on human embryos.