P-283 Is it time to abandon the practice of double embryo transfer?
Authors: Balachandren N , Mavrelos D , Seshadri V , Saab W , Kastora S , Yasmin E 
Published: June 2023

Abstract

Study question
Can single embryo transfer (SET) with euploid embryos be an effective strategy for improving livebirth rate (LBR) and reducing multiple pregnancy rate (MPR)?

Summary answer
SET of euploid embryos leads to higher LBR and lower MPR per embryo transfer cycle compared to DET of untested embryos in all age groups.

What is known already
Multiple pregnancy, IVF, and advanced maternal age are independently associated with adverse obstetric outcomes and their coexistence is likely to lead to aggravation of obstetric risks. DET is often recommended in women aged over 37 with the aim of improving LBR but at the cost of significantly higher MPR.
Preimplantation genetic testing for aneuploidy (PGT-A) was pioneered to select euploid embryos for transfer. We evaluate whether utilization of PGTa with a subsequent transfer of a single euploid embryo can be an effective strategy for reducing MPR and achieving higher LBR compared to DET of untested embryos.

Study design, size, duration
This is retrospective national cohort study using data from the UK Human Fertilisation and Embryology Authority (HFEA). We analysed 137, 186 IVF treatment cycles performed between 2017-2018 in the UK. Other than grouping by maternal age, no further confounders were controlled for. Both fresh and frozen transfers were included.

Participants/materials, setting, methods
We included all IVF treatment cycles. Cycles undertaken for donation or embryo storage were excluded. Cycle parameters including age, ethnicity, the number of previous cycles, previous infertility history, previous pregnancy outcomes, gestational age at delivery, birthweight and early pregnancy outcomes were evaluated.
We compared the LBR and MPR per embryo transfer cycle following a SET of a euploid embryo (PGTa SET) vs. a DET of untested embryos.

Main results and the role of chance
PGTa was utilised in 1990 IVF treatment cycles, of which 1521 had a SET of a euploid embryo (76%, 95% CI 75-78%). Of 135, 195 IVF cycles in which PGTa was not utilised, there 37, 281 had DET of untested embryos (28%, 95% CI 27-28%). There were 319 IVF treatment cycles in which there were no euploid embryos to transfer following PGTa (16%, 95% CI 14-18%). In the untested group, there were 16, 680 IVF treatment cycles in which there were no embryos to transfer (12%, 95% CI 12-13%).
Per embryo transfer cycle, the LBR was significantly higher and the MPR was significantly lower in all age groups in PGTa SET group vs. DET of untested embryos group (including those aged under 35) (43.7% vs. 31.4%, p &lt; 0.001 and 0.3% vs. 8.4%, p &lt; 0.0001, respectively).

Limitations, reasons for caution
It is unclear whether the HFEA dataset includes all intended collections when assessing outcomes, thus we were unable to report on outcomes per cycle started.

Wider implications of the findings
Advanced maternal age is associated with increased perinatal risk and maternal morbidity. This population are particularly vulnerable to multiple pregnancy. PGTa followed by SET of a euploid embryo is an effective strategy for reducing MPR and improving LBR in all age groups.

Trial registration number
not applicable