Couples frequently use frozen embryos to increase their chances of becoming pregnant after a single IVF or ICSI round. When using frozen embryos, the embryos must first be thawed before being transferred to the uterus. A uterus can be prepared in three ways for the transfer of a thawed frozen embryo.
- Menstrual cycle in its natural state
The embryo can be transferred naturally if you ovulate frequently. We must monitor the growth of your eggs, the thickness of your endometrial lining (uterine lining), and your hormone levels to determine when the embryo should be transferred.
We can track the growth of your eggs and assess the thickness of your endometrial lining with a vaginal ultrasound. A blood test is required to determine hormone levels. Your embryo can be transferred if the follicle size, endometrial thickness, and hormone levels are all normal.
After the right amount of days, your embryo is placed in the uterus (six days later if a blastocyst is to be transferred or four days later if a day 3 embryo is to be transferred). There is a chance of natural pregnancy if you have intercourse during the cycle, in addition to the likelihood of embryo transfer success.
- Ovulation induction with FSH
FSH ovulation induction is a good option if you’re not ovulating regularly and have enough eggs in your ovary to ovulate.
FSH is a hormone injection that promotes the development of many eggs. Because of the danger of multiple pregnancies, you may be asked to refrain from sexual activity if two or more eggs mature in the ovary. If natural conception is possible, there is a possibility of twinning, just as there is with natural cycle FET. Injections of human chorionic gonadotropin (HCG) can trigger ovulation.
- The replacement of the hormones cycle.
If you’re not ovulating regularly, have a low quantity of good eggs, or are experiencing endometrial thickening, a hormone replacement cycle may be the best option for you.
To prevent egg formation from the ovary interfering with hormone levels, which impact the endometrial lining, a GnRH agonist (General) is often administered. Every three days, a table or patch is put to the skin to help thicken the endometrial lining. A second hormone, progesterone, is given vaginally once the endometrial lining has reached the desired thickness (Utrogestan, Endometrin or Crinone).
After the progesterone is started, the embryo is transferred to the uterus at the right moment. Pregnancy screenings are required via blood tests, and if the test is positive, hormones must be continued until the foetus is about eight or nine weeks old, at which point the placenta generates enough hormones to keep the pregnancy in place. After 10 weeks of pregnancy, the hormone dosages are gradually discontinued.