Effect of age dependent embryo transfer policy on singleton and twin pregnancy outcomes after assisted reproductive technology

Abstract

To evaluate an embryo transfer protocol based on age and embryo quality. A prospective cohort study. We evaluated all fresh embryo transfers between January 2007 and February 2011. The number of embryos transferred were predetermined by a fixed protocol taken into account female age, embryo quality and cycle number.For women <35 years, with at least one good quality embryo available and the first cylce:1 embryo was transferred (eSET), otherwise 2 embryos were transferred.In a subsequent cycle(s) 2 embryos were transferred(DET).For women 35-38 years:2 best quality embryos were transferred (DET).For women ≥39 years:3 embryos were transferred (TET).The outcome was ongoing pregnancy rate and twin pregnancy rate.A multivariable logistic regression analysis was performed to determine differences between singleton and twin pregnancies. 2640 fresh embryo transfers were performed.In the eSET group 610 embryo transfers were performed, resulting in 169 pregnancies (28%) of which 8 twin pregnancies (5%).After a failed first cycle 370 transfers with DET performed in women with age < 35 years, resulting in 105 pregnancies (28%) and 35 twin pregnancies (33%).In the DET ≥35 -38 years group 770 cycles were performed, resulting in 157 pregnancies (20%)and 30 twin pregnancies (19%).In the TET group 631 transfers were performed, resulting in 88 (14%) and 15 twin pregnancies (17%).In 259 cases the embryo transfer protocol was violated.A multivariable analysis for women aged 35-38 years showed that age and top quality embryo had no significant influence on twin pregnancies compared to singletons. In women with poor prognosis TET is safe.In order to reduce twin pregnancy rates while maintaining optimal pregnancy rates,further research is necessary to identify women with different prognostic profiles.We should not just considering age but also take different prognostic factors into account,to develop an evidence-based and ‘patient tailored’ transfer policy.