Comparison of pregnancy outcomes in 3- and 5-day frozen embryo transfer cycles with blastocysts in normoresponder women

Comparison of pregnancy outcomes in 3- and 5-day frozen embryo transfer cycles with blastocysts in normoresponder women

A controlled, double-blind, randomized, parallel-group, on 148 patients. Randomization using a computerized random allocation sequence (https://www.sealedenvelope.com/).

Double-blind, randomized clinical trial. Infertile women referred to the Milad Infertility Center between 1402-1404 who met the inclusion criteria. Sample size is calculated as 74 in each group. On thetransfer day, in the intervention group, a 5-day embryo and in the control group, 3- and 5-day embryos are transferred.

Infertile women (18-41 years), normal uterine cavity, normal ovarian response to stimulation, women undergoing infertility treatment with IVF or microinjection and having at least 3 frozen embryos, no history of endometriosis or endocrine disorders and hysteroscopic surgery, no severe male factor infertility, no poor ovarian response or excessive ovarian response. Exclusion criteria: Cervical insufficiency, endometrial thickness<7 mm on the day of embryo transfer, and unwillingness to continue the study.

Ovarian stimulation is performed using 2 protocols (Agonist or Antagonist). When at least three follicles reach 17 mm, 10000 units of HCG are administered and 36 h later, oocyte retrieval is performed. Embryos are frozen in the cleavage phase for three days. Endometrial preparation is performed with three regimens (letrozole, hormone therapy with estradiol valerate, or a planned regimen). On transfer day, in the intervention group, a 5-day embryo and in the control group, a 3-day embryo and a 5-day embryo are transferred by catheter (Cook, Australia).

Chemical pregnancy rate, Implantation rate and clinical pregnancy rate

Random assignment of eligible subjects to the study will be performed by an individual who is independent of the research team and has no involvement in the treatment process, participant follow-up, data collection, or recording. After the subjects have been identified as eligible for the study and their informed consent has been confirmed, they will be assigned to the study groups using a block randomization method (blocks of 4, 37 blocks). Randomization will be performed using a computerized random assignment sequence (https://www.sealedenvelope.com/).

To conceal, cards are prepared that identify the intervention and control groups (for example, A on the card indicates the intervention group and B indicates the control group). Then these cards are placed in opaque envelopes, which are sorted and numbered according to the sequence generated by the software, and patients are assigned to the intervention or control group based on the card inside the envelope. With this concealment method, neither the patient nor the statistical consultant knows the type of treatment being received, and the statistical consultant, when analyzing the data, sees the type of treatment in coded form (A and B).