Frozen Embryo Transfer Protocol

Transfer of cryopreserved/thawed embryos consists of:

1. Preparation of endometrial lining.
2. Thawing and culture of cryopreserved embryos.
3. Assisted Hatching and transfer of the surviving embryos into the uterus.
4. Establishment of pregnancy.

This is an example of an Cryopreserved Embryo Transfer treatment sequence. Actual treatment is individualized:

 

 

1. Preparation of Endometrial Lining

    

   When you decide to have your embryos thawed and transferred, please call us with the onset of your menstrual period. Oral contraceptives are started within the first seven days of the menstrual cycle. They are used to suppress the ovarian function and to begin the process of synchronization between the development of the endometrial lining and the development of your frozen/thawed embryos. Some cryopreserved embryo recipients do not need to take the oral contraceptives.

    

   One week before the estimated onset of the following menstrual period, Lupron injections begin and are continued for three to four weeks. Lupron "puts ovaries to sleep" and temporarily stops their production of estrogen and progesterone. This estrogen and progesterone secretion would interfere with the development of the endometrial lining.

    

   After approximately ten days of taking Lupron, a menstrual period will start. Within one to two weeks of the onset of the period, the recipient will begin taking estrogen (Vivelle) in the form of skin patches. The development of the uterine lining will be monitored by ultrasound and estrogen blood levels.

    

   When the endometrial lining is sufficiently developed, progesterone is added to the estrogen. The addition of progesterone opens the "window of receptivity" of the uterine lining and synchronizes its development with the development of your thawed embryos. Progesterone is given as a daily intramuscular injection for the first four days of its administration, after which it is administered as vaginal capsules.

    

2. Thawing and Culture of Cryopreserved Embryos

    

   You will need to decide and communicate to us how many frozen-thawed embryos you would like to transfer no later than the progesterone start day. To maximize the probability of a successful pregnancy, many couples have all their frozen embryos thawed, and transfer all the surviving embryos.

    

   As an alternative, you may decide on a number of embryos to be transferred. It is possible to thaw one straw at a time and keep thawing additional straws depending on the survival of the embryos until the desired number is reached. Since, typically, there are two embryos per straw, you could end up with one more surviving embryo than the number you wanted to transfer. You must decide and communicate to us which of the two thaw approaches we should use.

    

   It is quite uncommon to conceive with a triplet or higher order pregnancy even if several frozen-thawed embryos are transferred. Most pregnancies from cryopreserved embryos are single baby pregnancies.

    

3. Assisted Hatching and Transfer of the Surviving Embryos

    

   Assisted Hatching of embryos creates a "weak spot" in the eggshell of an embryo. This increases the likelihood of the embryo hatching out of the eggshell, implanting and resulting in a successful pregnancy.

    

   Cryopreserved/thawed embryo transfer (FET) is identical to a ”fresh” embryo transfer. There is no increased risk of birth defects in pregnancies from cryopreserved embryos compared with conceptions conceived through intercourse.

    

4. Establishment of Pregnancy

    

   A pregnancy test (PT) is scheduled approximately ten days after FET. As with “fresh” embryo transfer, the probability of a successful pregnancy with cryopreserved-thawed embryos depends on the number and quality of the transferred embryos. Typically over half of the cryopreserved embryos survive the cryopreservation-thawing process. The implantation rate of the surviving embryos is similar to "fresh" embryos.

    

   If the pregnancy test is positive, an ultrasound examination is scheduled two weeks later to visualize the implantation site and to look for a heartbeat. Once a heartbeat is seen, there is a 90% to 95% probability that the pregnancy will continue to a baby.

    

   There is no increased risk of birth defects with the Cryopreserved Embryo Transfer compared with conceptions conceived through intercourse or "fresh" IVF.

    

   You will continue to have your estrogen and progesterone blood levels monitored every one to two weeks. Six to eight weeks into the pregnancy, the placenta produces enough of its own estrogen and progesterone that the supplementation can be discontinued. Once you stop all your medications, the pregnancy becomes indistinguishable from a pregnancy conceived through intercourse.

If you have any questions regarding Cryopreserved Embryo Transfer please contact us by phone at 650-322-0500 or via email at care@BayIVF.com.