Effect of oocyte maturation rates on available embryo rates after in vitro fertilization
Objective To observe the effect of oocyte maturation rates[mature metaphase(MⅡ)oocytes rate,MⅡ ovum rate]on the embryo formation rate and MⅡ ovum utilization rate after in vitro fertilization(IVF).Methods The 408 cycles of single cavity oocyte retrieval and conventional fertilization(IVF)in Air Force Medical Center were retrospectively analyzed,which were divided into 6 groups according to the MⅡ ovum rate:197 in group A(an MⅡ ovum rate of ≥90%),105 in group B(80%to 90%),54 in group C(70%to 80%),28 in group D(60%to 70%),14 in Group E(50%to 60%),and 10 in group F(<50%).These groups were compared with respect to age,basal follicle stimulating hormone(FSH),basal follicle,dosage of gonadotropin(Gn)and days of use,estradiol(E2)levels the day chorionic gonadotropin(HCG)was injected,constituent ratio of the stimulation schedule,number of oocytes retrieved,MⅡ ovum,two pronuclear(2PN)rate,available embryo rate,and MⅡ ovum utilization.Results There was no significant difference in conditions of patients,constituent ratio of the stimulation schedule,processes of ovulation and the number of oocytes retrieved between these groups(P>0.05).The 2PN rate,number of available embryos,and the available embryo rate decreased with the MⅡ ovum rate,and the difference was statistically significant(F=25.530,2.384,8.685,P<0.001,=0.038,<0.001).However,there was no significant difference in MⅡ ovum utilization(F=0.316,P=0.903).The available embryo rate of group A(44.33±18.97)%was significantly higher than that of the other groups[group B(38.84±17.82)%,group C(36.34±18.21)%,group D(30.45±11.38)%,group E(25.21±11.38)%and group F(20.85±12.68)%],and the difference was statistically significant(P=0.011,0.004,<0.001,<0.001,<0.001).Conclusion Oocyte maturation rates in single cavity oocyte retrieval and conventional fertilization cycles are not associated with the ovulation promotion protocol.As the oocyte maturation rate decreases,the rate of normal fertilization and available embryos decrease significantly,especially when the MⅡ ovum rate is below 70%,but the oocyte maturation rate does not affect the quality of mature oocytes.
In vitro fertilizationRate of MⅡ ovum utilizationMⅡ ovum rateAvailable embryo rate