Why single embryo transfer may be right for you

A lot of our patients at InVia Fertility Specialists want twins! However, multiple pregnancy is associated with increased risks to both mother and babies. From a medical view point, it is much safer to have your twins one at a time! So, a relevant question is, “Why do we ever transfer more than one embryo?”

The answer lies in the fact that in humans a significant number of embryos are chromosomally abnormal and will not implant. This number varies based on patient age (30 – 50 % in younger patients and 70 – 100% in older patients). So, when we transfer two embryos in a 35 year old, we hope that at least one of them is chromosomally normal and will implant. However, in approximately 30% of patients, BOTH are chromosomally normal with a resultant twin pregnancy! As discussed in a related blog, the recommended number of embryos to be transferred varies based on patient age, embryo quality and other factors.

Is single embryo transfer right for me?

Single embryo transfer (SET) will not be suitable for every patient undergoing in vitro fertilization (IVF), however, your physician can tell you if you are the right candidate. Typically the right patient is one or more of the following:

• under 35 years of age
• undergoing your first IVF treatment
• undergoing an IVF treatment after a previously successful IVF outcome
• have a history of cervical incompetence
• have good quality blastocyst development
• an egg donor recipient

Why consider single embryo transfer?

For the right patient, SET largely removes the risks of multiple pregnancy without significantly reducing the chance of a successful outcome. With advances in vitrification (freezing) of embryos, and increased survival rates at thaw, frozen embryo transfers have success rates comparable to that of fresh transfer rates. Advances in extended culture in the lab have also increased the blastocyst formation rate, increasing the number of available blastocysts for freezing.

Can elective single embryo transferred be offered to almost ALL patients without compromising pregnancy rates?

The answer is possibly YES!

It is now possible to screen embryos for chromosomal abnormalities using a technique called preimplantation genetic diagnosis (PGD). I posted in a recent blog details of a study out of Reproductive Medical Associates of New Jersey showing that transferring just one chromosomally normal embryo during IVF is associated with the same delivery rates – but better obstetrical and pediatric outcomes – than the more standard procedure of transferring two unscreened embryos (DET).

The researchers also found that SET significantly lowered the likelihood of twins, preterm delivery, and low birth rate babies; as well as admission to the neonatal intensive care unit.

While this study did compared SET of blastocysts screened by PGD, which is an additional cost to the patient, versus DET of non-PGD embryos, the short term increase in cost should not be a deterrent. In terms of long term costs, the cost of PGD and having a singleton birth is significantly less than a twin birth needing neonatal care, as well as the other expenses associated with twin births.

If you are interested in SET or PGD or have questions if it is an option for you, please schedule an appointment with one of the Board Certified physicians at InVia Fertility Specialists.