Today, In Vitro Fertilization (IVF) has never been more successful, in regards to implantation rate and live birth rate, since its introduction in 1978. A part of this is due to improvements in culture systems and culture media, but also due to improved training and proficiency of embryologists. During the pioneering years of IVF in humans, overall pregnancy rates per treatment cycle were low.
Therefore, to increase the success rate of an IVF cycle, it has become an accepted practice to transfer two or even more embryos per patient, regardless of age or embryo quality, to the uterus. As a result, high-order multiples including twin pregnancies were on the rise.
Multiple pregnancies are associated with the increased risk of certain congenital abnormalities and other potential complications, which are attributed to an increase in maternal and perinatal mortality and morbidity, family stress, and increased costs for all parties involved.
The prime aim of any IVF procedure is to produce a live healthy infant. In this way, we can maintain a balance between the end result and the efforts, costs, and complications of the IVF cycle.
A patient’s autonomy represents a particular challenge, especially with an overwhelming desire for twin pregnancies after IVF. However, clinical experience also shows that many patients are confronted with dilemmas when deciding whether to choose one or two embryos for embryo transfer. The nature of some of these dilemmas may lie in:
- The emotional stress that a patient may be undergoing (urgency to get pregnant)
- The financial aspects of the treatment (cost to the infertile couple, which increases with no IVF insurance coverage)
- Statistical concerns (being aware of the low ongoing pregnancy rate per treatment cycle from national data)
Patient education is vital for encouraging patients to take an eSET as the only truly effective means to avoid multiple gestations. Support in their decision-making can include being made aware of a successful cryopreservation program of supernumerary embryos, which will help to maintain high pregnancy rates while improving the health of the resulting live births when performing eSET in good prognosis patients.
What patient population would be suitable in offering eSET? The fact is that women with the best chance of getting pregnant after infertility treatment are also at the highest risk of conceiving multiple gestations, usually patient cohort <35 years of age. The Center of Disease Control (CDC) published in their 2014 report that in good prognosis patients taking two Day 5 embryos for transfer, the incidence of twin pregnancies is about 44%, which is confirmed by our data. The criteria used for Fertility Centers of Illinois patients is that we recommend eSET if:
- Age <37 years
- Having their first cycle or having conceived in a previous IVF cycle
- Availability of one or more high-quality blastocysts.
Convincing patients to reduce the number of embryos transferred from two to one works only when a patient is convinced of the success of eSET. Looking at our nation, the CDC 2014 ART Success report observed a national average for performing eSET in patients less than 35 young of 28.5%. In 2016, FCI performed eSET in 65% of our patients younger than 35 years.
At Fertility Centers of Illinois, extended culture generates high pregnancy and implantation rates even when we are transferring single embryos instead of two embryos. Since 2007, we performed close to 1,900 eSET in a patient population with a mean age of 32.0 3.2 years.
Over the course of 10 years, we did not observe a decrease in the overall ongoing pregnancy rate in our program, but we did find a dramatic reduction of twins and a complete disappearance of high-order multiple pregnancies.
So far, we experience an implantation rate of 63.0% with a Baby-Take-Home rate of 56.0%, and a high-order multiple rate of less than 2%. For potential eSET patients, it is important to know that after completion of an IVF cycle, more than 90% of eSET patients’ supernumerary embryos were cryopreserved for future use. Those cryopreserved embryos achieve an outcome data similar to that of fresh transfers.
Medical contribution by Dr. Juergen Liebermann