P-282 Blastocyst transfer in advanced maternal age: Single versus double embryo transfer
Authors: Balfoussia D , Yeung A , Yamanouchi L , Rattos A , Salim R 
Published: June 2022

Abstract

Study question
Is there a role for elective single blastocyst transfer (eSBT) in advanced maternal age?

Summary answer
Double blastocyst transfer (DBT) versus eSBT resulted in higher live birth rates except for those undergoing their first cycle.

What is known already
Women with advanced maternal age are generally considered poorer prognosis patients with lower live birth rates compared to their younger counterparts. This often results in a higher likelihood of double embryo transfer in this group. This is not without risk as multiple pregnancy is associated with significant maternal and neonatal morbidity especially with advancing maternal age. In older women with blastocysts available for transfer, it is unclear who should be recommended double versus elective single transfer. The concept of the “good-prognosis” older woman remains elusive.

Study design, size, duration
This was a retrospective observational study looking at 511 IVF/ICSI cycles between January 2010 and January 2020. Treatment cycle details and clinical outcomes were entered prospectively into a dedicated clinic database. Data was retrieved and analysed using SPSS V25.

Participants/materials, setting, methods
The study was conducted in a large London IVF centre. Data was collected on women aged 40 or above undergoing an IVF/ICSI cycle with eSBT (Group 1, n = 79) or DBT (Group 2, n = 430). Women with more than three previous IVF attempts were excluded. eSBT was defined as a single blastocyst transfer with at least one further blastocyst available for cryopreservation. Subgroup analysis was performed for those undergoing their first cycle.

Main results and the role of chance
Data from 511 cycles was analysed. The mean age was 40.6±1.2years. The live birth rate was 27%. Group 1 was marginally younger (40.2±0.6 v 40.8±1.2, p &lt; 0.005) and was more likely to be undergoing their first IVF cycle (84% v 68%, p = 0.003). Those in Group 1 had more eggs collected (13.6±7.3 v 11.3±5.5, p = 0.009), more zygotes (8.9±4.7 v 7.3±3.6) formed and more blastocysts frozen (3.4±2.6 v 1.1±1.7, p &lt; 0005). More women in Group 1 had a top quality blastocyst (expansion of &gt; 2 and inner cell mass and trophectoderm of AA, AB, BA or BB) transfer (91% v 71%, p &lt; 0.005).
After logistic regression controlling for maternal age, number of previous IVF cycles and blastocyst quality, Group 1 had a lower likelihood of livebirth (aOR 0.550, 95%CI 0.306-0.988) but with a significantly lower multiple pregnancy rate (0% v 24%, p = 0.024).
Importantly, for those undergoing their first IVF cycle (n = 359), there was no difference in live birth rate in the two groups (aOR 0.617, 95%CI 0.329-1.156) after controlling for age and blastocyst quality but Group 2 had a higher multiple pregnancy rate (24% v 0%, p = 0.020).

Limitations, reasons for caution
This study is limited by its retrospective nature putting it at risk of information bias as it relied on accurate documentation of studied variables into the patient database. The study did not examine cumulative birth rates of fresh and subsequent frozen cycles in Group 1.

Wider implications of the findings
Women should have individualised counseling about number of blastocysts to transfer taking into account their circumstances. Those undergoing their first IVF attempt and with a blastocyst available for transfer, should be counselled that DBT is associated with a higher multiple pregnancy rate with no increase in overall live birth rate.

Trial registration number
Not Applicable