Follicles (FOs) of 16–22 mm produce more mature oocytes compared with small FOs as reported. In patients with poor ovarian response, late trigger results in premature luteinization, and an early trigger increases the number of immature oocytes. The purpose of this study was to demonstrate that metaphase II oocytes collected from FO of 11–15 mm results in similar pregnancy outcomes as metaphase II of oocytes collected from FO >16 mm when a dual trigger is used in patients with poor ovarian response.
Materials and method:
This was a prospective cohort study. A total of 122 patients were included according to the Bologna criteria for “poor ovarian responders”. From 2018 to 2020, controlled ovarian stimulation using antagonist protocols was used for ovarian stimulation. Two-dimensional ultrasound combined with hormonal assessment were used to monitor ovarian stimulation. Ovulation was induced with 0.2 mg gonadotropin-releasing hormone agonist and 5000 IU human chorionic gonadotropin when at least 1 FO ≥16 mm; 36 hours later, oocyte retrieval was performed. FO were collected separately. For all laboratory steps, oocytes were treated according to size FO. A single cleavage stage embryo was transferred. The luteal phase was supported with micronized progesterone. Excess embryos were cryopreserved according to FO size. If pregnancy did not occur, a single frozen embryo was replaced. Two groups of punctate FOs were analyzed: group 1 (G1) =246 FO size 11–15 mm, group 2 (G2) =238 FO size ≥16 mm.
Results:
In all, 122 cycles were started, 27 were cancelled. Forty-six fresh embryo transfers in G1 and 49 in G2 were performed, 31 frozen embryo transfers for G1 and 10 for G2. There were no significant differences in fertilization rate, clinical pregnancy rate (CPR), and live birth rate. Logistic regression adjusting the CPR to FO size and other influencing factors revealed no predictors for CPR and live birth rate.
Conclusion:
Study showed similar pregnancy outcomes regardless of FO size.