| Background:The birth of Louise Brown in 1978 was the culmination of decades of scientific research in reproductive medicine. Since then, an abundance of breakthroughs in both clinical medicine and basic science have allowed increasing numbers of infertile couples the chance to have a baby. Today, In Vitro Fertilization and Embryo Transfer (IVF-ET) is available throughout most of the civilized world, although the clinical pregnancy rate continued to improve, the technology has been troubled by high rate of abortion, prematuredelivery, multiple conception rate and so on. During the early days of IVF, options for the patient with supernumerary embryos included discarding them, donating them to another infertile couple, or donating them for use in experimental research. Intense efforts to develop various freezing/thawing techniques and cryoprotective agents eventually resulted in the first reported human pregnancy from a frozen embryo in 1983, which unfortunately ended in premature rupture of the membranes and termination of pregnancy at 24 weeks of gestation. Now frozen-thawed embryo transfer (FET) has become an important supplementary procedure in the treatment of infertility. It contributes an increase of cumulative pregnant rates following one cycle of oocyte retrival, reduces the cycles of controlled ovarian hyperstimulation-invitro infertilization, it also reduces the risk of multiple conception and the spending. Recentally,it has attractted our attention.Obsject:The aim of this study was to analyze predicting factors of Frozen-thawed embryo transfer.Method:A retrospective study was conducted on 326 frozen-thawed embryo transfer cycles and then analyzed the effects of recipient age, transfer programs in preparation of endometrium thickness and type,the peak of estrogen during the cycle, the number of transferred embryos and transferred good embryos on the implantation of cryopreserved human embryo and the clinical pregnancy rate in 2007.Results:Among the 796 thawed embryos from 326 frozen—thawed embryo transfer cycles, The average of recipients' age is 31.1±4.1 years . 165recipients achieved clinical pregnancy, the clinical pregnany rate is 50.6%. The number of embryo implantation is 235, the is 29. 5%. 449 good embryos were transferred. 2.4±0.6 embryos were transferred per cycle , 1.4±1.1 good embryos were transferred per cycle Among them, there were 6 triplet pregnancy:4 selective reduction of triplet pregnancy, 1 natural reduction of triplet pregnancy, 1 triplet pregnancy refused reduction, 56 bigeminal pregnancy:4 natural reduction of bigeminal pregnancy, 3 inevitable abortion. 97 singleton pregnancy: 14 inevitable abortion. 4 ectopic pregnancy, 2 heterotopic pregnancy. Patient' s age, endometrium thickness and type had no influence on the implantation rate and clinical pregnancy rate after cryopreservation(P>0. 05), and the number of transferred embryos also had no influence on the implantation rate and clinical pregnancy rate after cryopreservation(P>0. 05). The number of transferred good embryos had significant effect(P<0. 01) on the clinical pregnancy rate and superfoetation rate.The peak of estrogen level had significant effect(P<0. 05) on the embryo implantation rate and clinical pregnancy rate. Implantation rate in controlled ovarian hyperstimulation cycles is significant higher than that of natural cycle and hormone replacement treatment cycles(P<0. 05).Conclusion:Among the tested factors, the number of transferred good embryos has significant effect on the cryopreserved human embryo implantation. The peak of estrogen level during the cycle is also an important predicting factors of clinical pregnancy rate and implantation rate during the Frozen-thawed embryo transfer. Maybe Controlled ovarian hyperstimulation is a better method of endometrial preparation, further studies are still needed. |
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