Standardizing embryo transfer steps for frozen embryo transfers

Inclusion Criteria:

* The patient and her partner gave written, informed consent to participate in the clinical trial.
* The patient underwent a medically assisted procreation procedure using IVF or ICSI in accordance with the applicable law, did not have a fresh transfer, has all frozen embryos in the blastocyst stage, of which at least 1 is of good quality
* You and your partner are not currently taking part in or have not participated in any other clinical trial in the last 6 months.
* The patient's age on the day of screening ranges from ≥18 to ≤38 years.
* The patient's BMI on the day of screening ranges from ≥18 to \< 30.
* Both partners have normal infectious tests performed 6 months before ET and bacteriological tests performed one month before ET.
* The patient has had IVF or ICSI embryo culture performed in an incubator with a Time Lapse monitoring system and an Artificial Intelligence system (or if not, the embryo will be placed in the EmbryoScope after thawing) and has not had a fresh transfer (all embryos after stimulation and puncture have been frozen), and after thawing she has at least 1 good quality blastocyst evaluated before freezing by an embryologist as a good quality blastocyst or bl class. 3.2.2. The embryos have also been evaluated by AI prior to freezing and will be thawed in the future in order of the highest AI-confirmed rating.
* The patient has a normal uterus and endometrium at least 7 mm on ET.
* The patient must be prepared for cryotransfer in the ovulatory cycle with natural or induced letrozole, and after ovulation in the current cycle, take a progesterone preparation at the doses specified above for luteal phase supplementation.
* On the day of transfer (5th day after ovulation), the patient must have at least one thawed, developed embryo of good quality - pre-frozen blastocyst 3.2.2 thawed according to the highest AI rating.
* The patient must be qualified by the doctor for the procedure embryo transfer on day 5 after ovulation.
* Embryo transfer was performed without general anesthesia or other procedures and/or additional antispasmodic drugs prior to transfer (e.g. oxytocin antagonist) with the exception of routine preparation (drotaverine 1 table and 20 mg p.o. per hour prior to transfer).

Exclusion Criteria:

* Failure to meet the inclusion criteria.
* The patient was found to have abnormalities in the anatomical structure of the uterus and reproductive tract, which, according to the researcher, could reduce the chances of getting pregnant.
* The patient was diagnosed with endometrial polyp(s).
* The patient was diagnosed with submucosal or intramural uterine fibroids.
* The patient was diagnosed with fallopian tube hydromas.
* The patient was diagnosed with ≥3 endometriosis.
* The patient or her partner is a carrier of a genetic defect that may have an impact on lowering fertility.
* The patient or her partner is currently or has been undergoing cancer treatment in the past, which may have had a negative impact on fertility.
* The patient has had 1 unsuccessful embryo transfer in the past, which means no clinical pregnancy.
* During the trial transfer in the preceding cycle, difficulties in entering the uterine cavity (the so-called difficult transfer) were found or if the patient had had an embryo transfer in the past and it was described as difficult, even if she became pregnant as a result.
* Embryos are formed from eggs after PBB (polar body biopsy) of oocytes have been examined or have undergone genetic testing of embryos.
* The embryos were formed from oocytes after cryopreservation.
* Semen was obtained for a procedure other than normal ejaculation (retrograde bladder ejaculation, epididymis biopsy, testicular biopsy, M-TESE).
* The patient did not take progesterone for luteal phase supplementation.
* Inability to perform embryo transfer on day 5 after ovulation due to medical or random reasons.
* The patient has indications for general anesthesia or pre-transfer antispasmodic procedure/medication (oxytocin receptor antagonist other than Drotaverine, or others that may affect implantation (intralipid, neupogen, and other significant in the investigator's judgment).
* The patient is to have an incision made in the AH areola before the ET procedure.
* The patient wants to have Embryoglue used for transfer.
* The patient takes heparin, Clexane, Acesan, Relanium drugs on and after embryo transfer.