Polar body transfer restores the developmental potential of oocytes to blastocyst stage in a case of repeated embryo fragmentation.

PURPOSE: We aimed to determine the developmental potential of human reconstructed oocytes after polar body genome transfer (PBT) and to report the case of a woman with multiple cycles of severe embryo fragmentation. METHODS: Fresh and cryopreserved first polar bodies (PB1s) were transferred to enucleated metaphase II oocytes (PB1T), while fresh PB2s were removed from fertilized oocytes and used instead of the female pronucleus in donor zygotes. Reconstructed oocytes underwent intracytoplasmic sperm injection (ICSI) and were cultured to blastocyst. Biopsied trophectoderm cells of PBT-derived blastocysts were screened for chromosomes by next-generation sequencing (NGS). Then, cryopreserved PB1T was carried out in one woman with a history of several cycles of extensive embryo fragmentation, and the blastocysts derived from PB1T were screened for aneuploidy but not transferred to the patient. RESULTS: There were no significant differences in the rates of normal fertilization and blastocyst formation between fresh and cryopreserved PB1T and control oocytes. Of the three fresh and three cryopreserved PB1T-derived blastocysts, two and one blastocysts exhibited normal diploidy respectively. In contrast, 17 PB2 transfers yielded 16 two pronuclei (2PN) zygotes with one normal and one small-sized pronucleus each and no blastocyst formation. In the female patient, 18 oocytes were inseminated by ICSI in the fourth cycle and the PB1s were biopsied. Although the embryos developed from the patient's own oocytes showed severe fragmentation, the oocytes reconstructed after PB1T produced three chromosomally normal blastocysts. CONCLUSIONS: Normal blastocysts can develop from human reconstructed oocytes after PB1T. The application of the first PB transfers may be beneficial to patients with a history of poor embryo development and excessive fragmentation.

[Influence of patient age and the number of good-quality-embryos transferred on multiple gestation in in vitro fertilization and embryo transfer].

OBJECTIVE: To observe the influence of patient's age, and the number of transferred-good-quality-embryos on multiple gestation rates in in vitro fertilization and embryo transfer (IVF-ET) cycles. METHODS: In this retrospective study, a total of 4,395 patients who transferred fresh embryo between Jan 2004 and Nov 2006 was analyzed. According to the age, the patients were divided into 2 groups: aged < 35 (3,442 cycles) or aged >or= 35 (953 cycles). We regularly transferred 2 - 3 embryos. If the patients had only one embryo, one was transferred. And those patients who had only 2 embryos, even if they were more than 35 years old or it would be the second time for them to transfer, were transferred 2 embryos. The influence of female age and the number of good quality embryos transferred on the multiple gestation rates in IVF-ET cycle was analyzed. RESULTS: (1) The multiple gestation rate of the groups of 1 good quality embryo, 2 good quality embryos, or 3 good quality embryos transferred were 21.08% (35/166), 31.41% (413/1315), and 42.37% (75/177), respectively in women aged < 35, with a significant difference between them. The pregnancy rates of these groups were 29.64% (166/560), 51.63% (1,315/2,547), and 52.84% (177/335), respectively; there were no significant differences between 2 good quality embryos transferred group and 3 good quality embryos transferred group. (2) The multiple gestation rates of the groups of 1 good quality embryo, 2 good quality embryos, or 3 good quality embryos transferred were 19.51% (8/41), 20.65% (19/92), and 40.66% (74/182), respectively, in women aged >or= 35; there were no significant differences between 1 good quality embryo transferred group and 2 good quality embryos transferred group. The pregnancy rates of these groups were 19.07% (41/215), 33.70% (92/273), and 39.14% (182/465), respectively; there were no significant differences between 2 good quality embryos transferred group and 3 good quality embryos transferred group. (3) The pregnancy rate of the patients aged < 35 [48.17% (1,658/3,442)] was significantly higher than in women aged >or= 35 [33.05% (315/953)]. CONCLUSION: The transfer of 2 good quality embryos results in similar pregnancy rates and significantly reduced multiple gestation rates when compared to the transfer of 3 good quality embryos in women regardless of their ages.