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

Abstract

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.