IVF treatment and twins – role of multiple embryo transfer
One of my patients whom I was counselling for IVF treatment for her primary infertility recently asked me a very basic question about the procedure and its outcome. She asked me – “Doctor, can I conceive only twins with IVF?”. This again prompted me to think about this very important aspect of fertility treatment – the risk of multiple pregnancy resulting from multiple embryo transfers. Some big celebrities like Celine Dion, Julia Bradbury and Jennifer Aniston and our own Farah Khan have been in news for conceiving multiple babies with IVF and that somehow makes many women undergoing IVF treatment to think that IVF produces multiple pregnancy only. In this post, I will try to explain the reasons for multiple pregnancies resulting from IVF treatment and how can this be avoided.
According to global evidence, approximately 25% of total births resulting from ART treatment are twins, a rate much greater than in the general population (approximately one in 80 births). The incidence of triplets and quadruplets is also high among pregnancies resulting from IVF treatment. However, the majority (approx. 70%) of pregnancies resulting from IVF treatment are singletons. With an ever increasing focus on optimizing treatment outcome and reducing complications associated with IVF treatment, the risk of multiple pregnancies with IVF has become one of the most important considerations while planning the IVF cycle.
The process of implantation of an embryo in the womb is a complicated one and we still do not know what transpires between the embryo and the uterus when they come in contact with each other, and therefore, we do not completely understand the reasons for a positive or negative pregnancy outcome also. Since there is no test or procedure that can assure pregnancy with IVF – an expensive treatment not generally covered by insurance policies – the physicians naturally want to enhance the probability of pregnancy and consider putting in more than one embryos. The risk of multiple pregnancy in IVF cycle derives from this tendency among treating physicians to transfer more than one embryos inside the uterus in order to increase the odds of pregnancy.
Pregnancy rates with IVF treatment appear to peak with transfer of three or four embryos. However, the risk of multiple pregnancy also increases at the same time. Multiple pregnancy is associated with a higher rate of maternal, fetal and neonatal complications and is considered as the single biggest risk or complication of fertility treatment.
Good practice in IVF treatment aims to reduce the risk of multiple pregnancy whilst maximizing the overall chances of conception. This is achieved by proper patient selection and counselling.
Young women who have the best chance of conception, also have the highest chance of conceiving multiples. Therefore, I always offer them a single embryo transfer at a time and freeze the rest of the good quality embryos for later use.
An extended culture of embryos up to the day 5, called as blastocyst culture, helps in better embryo selection for transfer into the uterus. I advise blastocyst culture for patients with more than 3 good quality embryos and transfer a single blastocyst in such patients.
I also believe that treating physicians should counsel the patients that only success parameter in any IVF cycle is a healthy baby born to a healthy mother and reducing the number of embryos transferred in a cycle is a significant step to achieve that goal. Patients should be counselled about the risk associated with transferring many embryos and also explained that freezing the spare embryos and transferring them in subsequent cycles if needed would give them even better cumulative pregnancy outcome than putting back many embryos in one embryos transfer.
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