Extending the culture of cleavage-stage embryos to the blastocyst stage after warming increases the chance of live birth: does it have a regenerative effect?

PURPOSE: We aimed to evaluate the effect of extending the culture of cleavage-stage embryos to the blastocyst stage in vitrified-warmed cycles on pregnancy outcomes. METHODS: This is a retrospectively designed pilot study of a single center. All patients who applied for freeze-all cycle procedures during in vitro fertilization treatment were included in the study. Patients were classified into three subgroups. The embryos obtained were frozen at the cleavage or blastocyst stage. After a warming process, the cleavage-stage embryos were divided into two subgroups: the first group of embryos was transferred (vitrification day 3-embryo transfer (ET) day 3 (D3T3)) on the warming day; for the second group, the embryo culture was extended to the blastocyst stage (vitrification day 3-ET day 5 (after the extension of the embryo culture to the blastocyst stage), (D3T5)). Frozen blastocyst-stage embryos were transferred after warming (vitrification day 5-ET day 5 (D5T5)). Hormone replacement treatment was the only endometrial preparation regimen given during the embryo transfer cycle. The main outcome of the study was live birth rates. The clinical pregnancy rate and positive pregnancy test rate were determined as the secondary outcomes of the study. RESULTS: The study included a total of 194 patients. The positive pregnancy test rates (PPR) and clinical pregnancy rates (CPR) of the D3T3, D3T5, and D5T5 groups were 14.0% and 59.2%; 43.8% and 9.3%; and 56.3% and 39.6%, respectively (p < 0.001 and p < 0.001). The live birth rates (LBR) of patients in the D3T3, D3T5, and D5T5 groups were 7.0%, 44.7%, and 27.1%, respectively (p < 0.001). In subgroup analysis of patients with a poor number of 2PN embryos (defined as having < = 4 2PN embryos), the D3T5 group had significantly higher PPR (10.7%, 60.6%, 42.4%; p < 0.001), CPR (7.1%, 57.6%, 39.4%; p < 0.001), and LBR (3.6%, 39.4%, 21.2%; p: 0.001). CONCLUSION: Extending the culture after warming to the blastocyst stage may be a better alternative than a cleavage-stage embryo transfer.

Dydrogesterone primed luteal phase stimulation may be better than follicular phase stimulation in patients with diminished ovarian reserve.

OBJECTIVE: In this study, we aimed to compare the efficacy of luteal phase stimulation (LPS) and follicular phase stimulation (FPS) in two separate menstrual cycles (2-5 months intervals) of the same patient, utilizing LPS with dydrogesteron only. METHODS: This retrospective case control study was conducted with patients with diminished ovarian reserve (DOR) (Group 1) and infertile patients with Anti-Müllerian hormone >1.2 ng/mL (Group 2) undergoing two ovarian stimulations (FPS and LPS with dydrogesteron only) and two oocyte retrievals in two separate menstrual cycles (2-5 months intervals) in the Division of Reproductive Endocrinology and Infertility of Baskent University, Ankara, between April 2019 and December 2019. RESULTS: In group 1, the number of frozen embryos was significantly higher in LPS when compared to FPS; 1.71 vs. 0.54, (p < .001), respectively. In group 2, the number of frozen embryos was higher in LPS when compared to FPS (0.8 vs. 0.4) however the difference did not reach a statistical significance (p: 0.157). CONCLUSION: LPS may be beneficial especially in the patients with diminished ovarian reserve with follicular asynchronization in the menstrual onset. In addition, it should be kept in mind that dydrogesterone only may be used instead of gonadotropin-releasing hormone antagonist to prevent possible luteinizing hormone rise in LPS.