The number of embryos that should be transferred during any single IVF cycle is subject to debate. Some specialists advocate for elective single embryo transfer (or eSET), which signifies – as the name suggests – that women only receive one embryo implantation per IVF cycle.
Others argue that urging women with infertility to use eSET is unethical, as it reduces their pregnancy chances dramatically. Multiple embryo transfer gives women with infertility a higher chance of conception.
Which is the correct choice?
- Elective single embryo transfer
The argument for single embryo transfer is that it’s considered lower risk. Multiple embryo transfer is associated with – you guessed it – multiple births. Although the “idea” of twins may seem ideal to couples struggling with infertility, the reality is that multiple births are risky for both mother and baby. There is a higher chance risk of prematurity, handicap and mortality. The mother has increased risk of premature birth, low birth weight, cesarean section, gestational diabetes and pre-eclampsia. As only one embryo is implanted, the couple is not at risk of multiple births.
- Multiple embryo transfer
The argument against single embryo transfer: it’s considered unethical.
Although transplanting 4 to 5 healthy, good-quality embryos may increase the risk of multiple births in young women not challenged by infertility, the fact is that many women going through IVF do not have good-quality embryos. As older women have lower-quality embryos, their chances of pregnancy are significantly decreased. Even if some of the embryos do implant after IVF treatment, their chances of making it through the first trimester are low (miscarriage rates are high in older women). Is it fair for fertility specialists to reduce pregnancy chances in these women, some of whom may just have one chance at IVF treatment?
The correct choice depends on the individual patient.
In this video, Dr. Vitaly A. Kushnir M.D. from Center for Human Reproduction NYC highlights the different factors that drive the decision of embryo numbers – such as the amount of embryos available, quality of the embryos, the woman’s past medical history and her age.
The current guidelines for embryo transfer are laid out by the American Society for Reproductive Medicine. Keeping in line with Dr. Kushnir’s comments, the ASRM criteria outlines that an important factor in deciding the amount of embryos to transfer is the woman’s age.
For the moment, fertility centers follow the criteria marked out by the American Society for Reproductive Medicine. Don’t be afraid to ask your fertility specialist about the different options available for embryo transfer numbers. Hint: a fertility center giving individualized care will take into consideration your specific case and medical history before deciding which embryo transfer number would be most suited to your treatment.