70% of the frozen embryo transfers in the assisted reproduction department at KCRC are done during ovulatory cycles, where the corpus luteum produced after ovulation secretes the estrogen and progesterone necessary to maintain pregnancy. Frozen embryo transfer in the ovulatory cycle completely follows the natural human fertility law, and the fetus is conceived and grown in a physiological hormonal environment, avoiding the adverse effects of a supraphysiological hormonal environment. In many hospitals, even if a woman has normal ovulation, hormone replacement is used to prepare the endometrium. Because hormone replacement is expensive, uncomfortable, inconvenient, physiologically incompatible, and complicated, hormone replacement is only used for patients who are unable to do frozen transfer in ovulatory cycles, such as those with endometrial damage, ovarian failure, induced ovulation failure in anovulatory patients, early ovulation, menstrual dribbling, severe myometriosis after down regulation, unexplained infertility with failed natural cycle transfer, and so on. We do frozen transplants in ovulatory cycles whenever possible. Even in women with abnormal ovulation we induce ovulation by ovulation promotion and do not easily give up the opportunity to transplant in ovulatory cycles. Jiu Hospital was the first medical institution in China to abandon the slow freezing technique and fully adopt the vitrification freezing technique. Over the years, we have devoted ourselves to the research of freezing technique and endometrial preparation for frozen embryo transfer, and have passed on our valuable experience to our colleagues. KCFH was the first in the industry to discover that using precise embryo-endometrial synchronization can dramatically increase the success rate of frozen embryo transfer, and is simpler and less frequently monitored. Here is our method of embryo-endometrial synchronization: For women with ovulation on 24-32 days of menstrual cycle, ovulation monitoring usually starts on day 10-12 of menstruation. When the LH peak appears, if the endometrium is over 8mm, we will inject HCG and take oral Darvon to synchronize the development of endometrium and embryo. The timing of embryo thawing is decided according to blood hormone values. Generally, if LH level is below 20miu/ml and progesterone is below 1.0pg/ml and estrogen is not decreasing, HCG 10,000 units will be injected at 9pm on the same day, oral Duffetone will be started on the injection day plus 3 days, 2 capsules in the morning and 2 capsules in the evening, and embryos on the third day will be thawed in the morning of the injection day plus 5 days, and blastocysts will be thawed in the morning of the 7th day. If LH level is equal to or more than 20miu/ml, or progesterone is more than 1.0pg/ml, or estrogen is decreasing, HCG 10,000 units will be injected in the afternoon of the same day, and both oral Duffetone and thawing will be done one day earlier. Sometimes thawing is done half a day earlier depending on the embryo to accurately synchronize the embryo-endometrial development. Women with menstrual cycles longer than 32 days should be seen on day 3 of their menstrual cycle for oral letrozole, with different doses of letrozole used to induce ovulation depending on the length of the menstrual cycle and previous ovulation monitoring, with a follow-up visit on day 10 of the menstrual cycle to monitor follicular development. The method of embryo-endometrial synchronization is the same as the natural cycle. If you want to learn more please go to SuperStar Academic Videos and search my name to watch my lectures. In some women with normal menstrual cycle and no primary follicle development on day 12 of menstruation, suggesting abnormal ovulation, we will inject a low dose of HMG to promote ovulation and synchronize the same method as the natural cycle. In order to reduce your visits to the hospital, patients who plan to do cryo-transplantation should note that if your menstrual cycle is 28-32 days, ovulation monitoring should be started on day 12 of menstruation. Out-of-town patients can first monitor their follicles and endometrium with local ultrasound, while measuring the LH peak with urine ovulation test paper, and if the LH peak starts to appear, they should come to Jiu Hospital for blood ultrasound. If your period is shorter than 28 days, monitoring ovulation should be done earlier. If your menstrual cycle is shorter than 23 days, longer than 32 days, thin lining, ovulation before the tenth day of your period or preparing for hormone replacement, you should come to Jiu Hospital on the third day of your period in all these cases. If the doctor has already made arrangements, follow the plan, such as those who have already scheduled hormone replacement 14 days for follow-up after hysteroscopy, or those who have already scheduled to take Letrozole before coming for follow-up after menstrual disorders, etc., follow the plan to reduce unnecessary visits. Urine LH measurement should pay special attention to the fact that only the C line, the T line does not show at all is negative. If the T line shows, even if it is very light, it means that the LH peak begins to appear, you should go to the hospital to draw blood and ultrasound, do not wait until the T line is as deep as the C line, because some people’s LH summit is always lower and the T line is always shallower. LH cannot be measured past the peak and special attention should be paid to it. It is recommended that you use the morning urine to measure it.