Journal Article

Comparisons of benefits and risks of single embryo transfer versus double embryo transfer: a systematic review and meta-analysis

Peng, Yangqin, Tan, Jing, Xiong, Yiquan, Ma, Shujuan, Hu, Liang, Wang, Xiaojuan, Gong, Fei, Tang, Yi

2022

Overview

Background Evidence referring to the trade-offs between the benefits and risks of single embryo transfer (SET) versus double embryo transfer (DET) following assisted reproduction technology are insufficient, especially for those women with a defined embryo quality or advanced age. Methods A systematic review and meta-analysis was conducted according to PRISMA guidelines. PubMed, EMBASE, Cochrane Library and ClinicalTrials.gov were searched based on established search strategy from inception through February 2021. Pre-specified primary outcomes were live birth rate (LBR) and multiple pregnancy rate (MPR). Odds ratio (OR) with 95% confidence interval (CI) were pooled by a random-effects model using R version 4.1.0. Results Eighty-five studies (14 randomized controlled trials and 71 observational studies) were eligible. Compared with DET, SET decreased the probability of a live birth (OR = 0.78, 95% CI: 0.71–0.85, P <  0.001, n  = 62), and lowered the rate of multiple pregnancy (0.05, 0.04–0.06, P <  0.001, n  = 45). In the sub-analyses of age stratification, both the differences of LBR (0.87, 0.54–1.40, P  = 0.565, n  = 4) and MPR (0.34, 0.06–2.03, P  = 0.236, n  = 3) between SET and DET groups became insignificant in patients aged ≥40 years. No significant difference in LBR for single GQE versus two embryos of mixed quality [GQE + PQE (non-good quality embryo)] (0.99, 0.77–1.27, P =  0.915, n  = 8), nor any difference of MPR in single PQE versus two PQEs (0.23, 0.04–1.49, P =  0.123, n  = 6). Moreover, women who conceived through SET were associated with lower risks of poor outcomes, including cesarean section (0.64, 0.43-0.94), antepartum haemorrhage (0.35, 0.15-0.82), preterm birth (0.25, 0.21-0.30), low birth weight (0.20, 0.16-0.25), Apgar1 < 7 rate (0.12, 0.02-0.93) or neonatal intensive care unit admission (0.30, 0.14-0.66) than those following DET. Conclusions In women aged < 40 years or if any GQE is available, SET should be incorporated into clinical practice. While in the absence of GQEs, DET may be preferable. However, for elderly women aged ≥40 years, current evidence is not enough to recommend an appropriate number of embryo transfer. The findings need to be further confirmed.

• Publisher: BioMed Central,BioMed Central Ltd,BMC
• Subject: Age groups / Birth weight / Cesarean section / Citations / Clinical medicine / Clinical trials / Double embryo transfer / Embryo / Embryo transfer / Embryo Transfer - adverse effects / Embryo Transfer - methods / Embryonic development / Embryos / Endocrinology / Female / Hemorrhage / Humans / Infant, Newborn / Infants (Newborn) / Live birth rate / Low birth weight / Male / Medicine / Medicine & Public Health / Meta-analysis / Miscarriage / Mortality / Multiple births / Multiple pregnancy rate / Neonatal intensive care / Neonates / Obstetrics / Patients / Perinatal complication / Population / Pregnancy / Pregnancy Outcome - epidemiology / Pregnancy, Twin - physiology / Pregnancy, Twin - statistics & numerical data / Premature birth / Reproductive Medicine / Review / Risk Assessment / Single embryo transfer / Single Embryo Transfer - adverse effects / Single Embryo Transfer - methods / Single Embryo Transfer - statistics & numerical data / Systematic review / Transplants & implants / Twins