With a good quality blastocyst, single embryo transfer remains the best choice - Fertility and Sterility

The goal of assisted reproductive technology is to achieve a healthy singleton birth. However, multiple gestation pregnancies due to transfer of two or more embryos remain a well-known complication of in vitro fertilization (IVF) despite the increase in maternal and neonatal risks (1x1Pinborg, A. Morbidity in a Danish National cohort of 472 IVF/ICSI twins, 1132 non-IVF/ICSI twins and 634 IVF/ICSI singletons: health-related and social implications for the children and their families. Hum Reprod. 2003; 18: 1234–1243 Crossref | PubMed | Scopus (139) | Google ScholarSee all References)(1). The best way to reduce multiple gestation pregnancies and the associated risks is by transferring fewer embryos. While improvements in embryo culture techniques and increased utilization of blastocyst transfer have increased single-embryo transfer (SET) rates in the U.S., double embryo transfer (DET) is still common and multiple birth rates remain unacceptably high. In 2014, 23% of women under age 38 who had a successful IVF cycle had a twin gestation (2x2American Society for Reproductive Medicine. Guidance on the limits to the number of embryos to transfer: a committee opinion. Fertil Steril. 2017; 107: 901–903 Abstract | Full Text | Full Text PDF | PubMed | Scopus (26) | Google ScholarSee all References)(2). Real or perceived increases in live birth rates drive providers and patients to choose to transfer more than one embryo, with multiple births being an acceptable side effect for many patients. While there is still an argument to be made in favor of dual embryo transfer in certain situations (advanced maternal age, no good quality embryos to transfer), efforts have been made to determine which factors may predict success with SET. The present prospective cohort study by Dobson et al. (3x3Dobson, S.J.A., Lao, M.T., Michael, E., Varghese, A., and Jayaprakasan, K. Effect of transfer of a poor quality embryo along with a top-quality embryo on the outcome during fresh and frozen IVF cycles. Fertil Steril. 2018; 110: 655–660 Scopus (1) | Google ScholarSee all References)(3) compares live-birth rates and multiple-birth rates in fresh and frozen embryo transfer cycles among patients who underwent SET with a top-quality blastocyst (AA, AB, BA, BB) to the following groups: SET with a poor quality embryo (AC, CA, BC, CB, CC), DET with two top-quality embryos; DET with a top-quality and a poor quality embryo; and DET with two poor quality embryos. They found that the addition of a poor-quality embryo to a top-quality embryo did not increase the live-birth rate but increased the