There is always a chance of twins with any pregnancy, but most of our IVF pregnancies are a single baby. The risk of twins is affected by how many embryos are transferred into your uterus, your age, the stage of the embryos (day 5 or 6 blastocyst-stage embryos are more likely to implant than day 2 or 3 cleavage-stage embryos), and the quality of the embryos. If you are under 35 with high quality embryos, there is about a 40% chance of twins if two embryos are transferred, and less than a 5% chance of twins with one embryo transferred – a single embryo can split into identical twins. Blastocysts are more likely to split.
Identical twins from IVF is a rare event. Most twins from IVF are non-identical, from two different embryos. Here at Overlake Reproductive Health, we only implant one healthy embryo at a time limiting the risk of multiples. Not all pregnancies that start as twins end as twins – some twin pregnancies result in miscarriage of one twin and survival of the other one so that you end up with a single baby.
Single Embryo Transfer (SET) is preferable because one baby at a time is safer for all involved. Other IVF clinics implant multiple embryos at a time to increase their IVF success rates. We use PGT to genetically test each embryo before we insert it which limits the chance of early miscarriage. So even though we insert one embryo per cycle, our success rates are among the highest in the country. Plus, because our embryos are frozen, if one cycle does not result in a pregnancy, you can insert a second embryo in a following month.
Talk to your MD about your concerns regarding twins and together you can decide the right number of embryos to transfer. They can give you specific guidance as they know your individual situation. We put our patient’s health first so the risk of twins with our IVF process is extremely low.