OBJECTIVE: To investigate whether sperm from different males can influence fertilization and embryo development. DESIGN: To use an egg-sharing model, in which the eggs from one woman are shared between herself and a recipient, and different spermatozoa are used to fertilize the eggs. SETTING: Assisted Conception Unit, Birmingham Women's Hospital, Edgbaston, United Kingdom. PATIENT(S): Infertile women undergoing egg sharing. INTERVENTION(S): In vitro fertilization (IVF). MAIN OUTCOME MEASURE(S): Fertilization rates and the mean day 2 or 3 embryo score (cell number X grade) were examined for egg-sharing pairs. A comparison was also made for pairs in which intracytoplasmic sperm injection (ICSI) and IVF was used as the insemination method. A paired samples t-test was used to compare the sharer and recipient results. RESULT(S): Pregnancy rates did not differ between sharer and recipient couples. Interestingly, when comparing fertilization, there was a significant difference (P<.05) in favor of IVF over ICSI. When comparing embryo development between egg-sharing pairs, we found that approximately 30% of patients showed a difference in mean embryo score of >or= 5 in all embryo development and 14% in the quality of embryos available for transfer. CONCLUSION(S): We showed that the egg-sharing model is a successful alternative for the treatment of women who required donated eggs. More important, the egg-sharing model shows that, in a certain percentage of couples, differences in early embryo development are paternally influenced.
OBJECTIVE: To investigate whether sperm from different males can influence fertilization and embryo development. DESIGN: To use an egg-sharing model, in which the eggs from one woman are shared between herself and a recipient, and different spermatozoa are used to fertilize the eggs. SETTING: Assisted Conception Unit, Birmingham Women's Hospital, Edgbaston, United Kingdom. PATIENT(S): Infertile women undergoing egg sharing. INTERVENTION(S): In vitro fertilization (IVF). MAIN OUTCOME MEASURE(S): Fertilization rates and the mean day 2 or 3 embryo score (cell number X grade) were examined for egg-sharing pairs. A comparison was also made for pairs in which intracytoplasmic sperm injection (ICSI) and IVF was used as the insemination method. A paired samples t-test was used to compare the sharer and recipient results. RESULT(S): Pregnancy rates did not differ between sharer and recipient couples. Interestingly, when comparing fertilization, there was a significant difference (P<.05) in favor of IVF over ICSI. When comparing embryo development between egg-sharing pairs, we found that approximately 30% of patients showed a difference in mean embryo score of >or= 5 in all embryo development and 14% in the quality of embryos available for transfer. CONCLUSION(S): We showed that the egg-sharing model is a successful alternative for the treatment of women who required donated eggs. More important, the egg-sharing model shows that, in a certain percentage of couples, differences in early embryo development are paternally influenced.