If after an IVF procedure cryopreserved embryos remain and a couple plans another pregnancy in the future (or if the pregnancy did not occur after the first IVF attempt), these embryos can be later on transferred to the patient’s uterus.
There are several options for preparing for the cryo-embryo transfer (frozen embryo transfer). A transfer in the natural cycle involves monitoring the growth of the dominant follicle and endometrium and determining the day of ovulation. Then, after waiting for the time corresponding to the “age” of the embryos, they are thawed and transferred to the uterine cavity. The advantage of this method is that an embryo transfer occurs in the natural cycle without prescribing medications.
A transfer in the natural cycle is not applicable for all patients (for example, it cannot be carried out in patients with chronic anovulation). In such cases, the embryo transfer takes place in a modified cycle with hormone replacement therapy. In terms of effectiveness, this method is equal to the transfer of cryopreserved embryos in the natural cycle, but requires administration of hormonal drugs.
All embryos after warming undergo an assisted hatching procedure aimed at facilitating the release of an embryo from a pellucid zone. The point of this micromanipulation is the incision of the embryo pellucid zone, which can be done in various ways. In our clinic, assisted hatching is performed with a laser.
Cryopreserved embryos are the property of the couple and their transfer into the uterus is possible only with the consent of both spouses.