IVF is one of the most widely applied Artificial Reproductive Techniques used the world over for combating complex infertility issues. The procedure is aimed at helping infertile couples to have a single, healthy baby by implanting a lab-prepared embryo(s) in the uterus of the woman. It follows a stringent protocol, with every step being adhered to in a strict manner.

One of the key questions related to IVF pertains to the number of embryos transferred during the procedure. The answer to this one is a little tricky because a choice has to be made between the chances of success of IVF treatment and the risk of multiple pregnancies. While the specialist can guide a couple in decision-making, the choice belongs to the latter as they are the ones bearing the financial and emotional cost of the procedure.

Deciding the number of embryos transferred- The Double Edged Sword

Medical technology has made phenomenal progress in the present time, with experts being able to synthesize embryos by combining eggs and sperms in a lab dish. Though something so miraculous has become possible, technically nothing can be done to make an embryo implant itself in the uterus. Consequently, the success rate of IVF is restricted to only 40% per cycle, as the majority of embryos are not able to become babies.

The number of embryos transferred for implantation has a direct influence on the success rate of IVF. Consequently, couples may be tempted to ask for multiple embryo transfer to maximize their chances of conception. But this one carries the risk of multiple pregnancies, which is dangerous for both, the mother as well as the babies. Premature labor and birth defects may be some of the complications that may surface in such cases. At the same time, couples may not want to opt for single embryo transfer because it brings down the chances of conception dramatically and the cost and effort involved in the IVF cycle may end up wasted.

Normally, the number is restricted to two per cycle as it is considered as an optimal one, because most couples would rather have twins than not be pregnant at all. The option has another benefit that the couple gets the chance to complete their family in a single IVF attempt, if it turns out to be successful. In some countries, it is mandatory by law to transfer only two embryos in IVF and this makes the decision less complicated for the couples as well as the specialist.

Parameters considered for making the big decision

Embryo implantation is the basis of success of IVF and several biological parameters have an impact on the same. These parameters need to be kept in mind while deciding the number of embryos to be transferred in the uterus for being implanted. These include the maternal age, embryo quality/grade and the day of embryo transfer (whether it is being transferred on day 3 or day 5, the blastocyst stage). Certain secondary factors which influence the decision making are the fertility history of the couple, the number of failed IVF cycles, endometrial receptivity, use of donor eggs/embryos and the preference of the patient.

Clinics normally devise a tailor-made approach for each couple when it comes to deciding the number of embryos transferred in each case. For instance, women who are below 30 and are going through their first IVF attempt are recommended two embryos transferred (for day 3 Grade A embryo). The number would increase to three for women aged between 30 and 38 and beyond that age, they would be asked to try with four embryos (as the risk of multiple pregnancies goes down with maternal age).

The calculation may be affected by factors such as embryo quality, previous failed IVF attempts, endometrial receptivity, transfer stage and use of donor eggs. Poor grade embryos, multiple failed IVFs and poor endometrial receptivity may have the specialist go for a larger number of embryos, while the number may be reduced if the older couple is using donor embryos from a younger woman. Similarly, blastocyst stage transfer has better chances, so patients can opt for lower number of embryos.

Though the algorithm is helpful for the specialist in assisting the patients to decide the number of embryos they would like to be transferred, the final decision is that of the patient alone. In addition to the above mentioned medical factors, the patient may need to consider certain personal issues while making the decision. Their willingness to take the risk of multiple pregnancies (and whether they would be ready to opt for selective fetal reduction if “higher order multiple” does occur) and also bear the financial implications of the same is one of them. Also, some couple may be more than eager to go for it because this one may be their last IVF attempt.

Gaudium IVF is a acclaimed IVF Centre, where patients are not only given the best treatment for diverse infertility problems but also helped for making informed decisions for complicated issues such as number of embryos to be transferred during IVF. Visit Gaudium IVF Centre for a free second opinion from the award-wining specialist, Dr Manika Khanna.