When it comes to scheduling an embryo transfer, deciding how many embryos to transfer, at which stage of embryo development, and what type of ovulation induction will the women undergo for endometrial preparation is crucial.
In Croatia, embryos can be cultured till day 6 of embryo development. Thus, the embryo can be transferred at a very early stage or conversely be cultured to the blastocyst stage.
Single vs two embryo transfer
In Croatia, a maximum of 2 embryos per transfer is allowed. Three-embryo transfers can be done only in the following exceptional cases:
- Women over 38 years old
- Poor ovarian reserve
- Repeated IVF implantation failure
- Patients suffering from cancer
- Severe male factor infertility
It is true that chances of success are higher with two-embryo transfers than with single embryo transfers, being this the reason why many couples go for the former option. However, patients should always follow medical advice to reduce the risks that may arise during pregnancy.
Deciding how many embryos to transfer should be based on a medical risk-benefit assessment. Multiple embryo transfers bear the risk of multiple births, which at the same time increases the number of potential complications during pregnancy, affecting both the mother and the babies.
Each case should be assessed individually, because some women may have a greater predisposition for suffering from other complications such as preeclampsia. For this reason, taking into account the maternal age, embryo quality, endometrial receptivity, and the cause of infertility, among other factors, is essential for making informed choices.
Preparing the uterus for embryo transfer
For the endometrial structure to reach the ideal measurements to favor embryo implantation, women should take medications based on estrogens for ovulation induction. Estrogens can be administered either through patch or mouth route.
Endometrial growth is monitored through ultrasound scan. The IVF embryo transfer day will be scheduled once a trilaminar endometrial pattern of 7-10 mm is reached. That is when the embryo(s) are able to attach and implant, thereby confirming that pregnancy has occurred.
A bit earlier and after the transfer, women should take progesterone, either orally or via vaginal suppositories. It is the doctor who will determine when to stop the treatment, which is usually a few weeks after a pregnancy is confirmed.
Anesthesia is not required for the embryo transfer, given that it is a simple, painless procedure, similar to intrauterine insemination. A catheter is inserted into the uterus for the purpose of placing the embryos in the uterine cavity. It is done through ultrasound-guided embryo transfer.
After the transfer, women should lie down for 20 to 30 minutes before leaving the clinic, and then she can continue with her normal lifestyle. The pregnancy test can be taken 2 weeks later approximately.