OBJECTIVE: Oocyte degeneration often occurs after intracytoplasmic sperm injection (ICSI), and the risk factor is low-quality oocytes. The follicular fluid (FF) provides a crucial microenvironment for oocyte development. We investigated the relationships between the FF volume aspirated from individual follicles and oocyte retrieval, oocyte maturity, oolemma stretchability, fertilization, and development. METHODS: This retrospective study included data obtained from 229 ICSI cycles. Ovarian stimulation was performed according to a gonadotropin-releasing hormone antagonist protocol. Each follicle was individually aspirated and divided into six groups according to FF volume (<1.0, 1.0 to <2.0, 2.0 to <3.0, 3.0 to <4.0, 4.0 to <5.0, and ≥5.0 mL). Oolemma stretchability during ICSI was evaluated using a mechanical stimulus for oolemma penetration, that is, the stretchability was assessed by oolemma penetration with aspiration (high stretchability) or without aspiration (low stretchability). RESULTS: Oocyte retrieval rates were significantly lower in the <1.0 mL group than in the ≥1.0 mL groups (46.0% [86/187] vs. 67.5%–74.3% [172/255 to 124/167], respectively; p<0.01). Low oolemma stretchability was significantly more common in the <1.0 mL group than in the ≥1.0 mL groups during ICSI (22.0% [13/59] vs. 5.8%–9.4% [6/104 to 13/139], respectively; p=0.018). There was a relationship between FF volume and oolemma stretchability. However, there were no significant differences in the rates of fertilization, cleavage, ≥7 cells at day 3, and blastocyst development among all groups. CONCLUSION: FF volume is potentially associated with the stretchability of metaphase II oolemma during ICSI. Regarding oolemma stretchability, ensuring a uniform follicular size during ovarian stimulation is crucial to obtain good-quality oocytes.
Blastocyst ; Clothing ; Female ; Fertilization ; Follicular Fluid* ; Gonadotropin-Releasing Hormone ; Humans* ; Infertility ; Membranes ; Metaphase ; Oocyte Retrieval ; Oocytes ; Ovarian Follicle ; Ovulation Induction ; Retrospective Studies ; Risk Factors ; Sperm Injections, Intracytoplasmic*

OBJECTIVE: The decision to use in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), or split insemination (IVF-ICSI) in the first cycle is based on the number of motile sperm. Hence, total fertilization failure (TFF) often occurs during IVF cycles, despite normozoospermia. To investigate whether the cumulative motile swim-up spermatozoa percentage at 22 hours post-insemination (MSPPI) is an indicator for ICSI, we analyzed TFF, fertilization, blastocyst development, chemical pregnancy, clinical pregnancy, and live birth rates. METHODS: This prospective study was performed using data obtained from 260 IVF cycles. At 22 hours after insemination, the remaining swim-up spermatozoa were observed and divided into six groups according to MSPPI (<10%, 10% to <30%, 30% to <50%, 50% to <70%, 70% to <90%, and 90% to 100%). RESULTS: Regardless of the ejaculated motile sperm concentration (0.6–280×106/mL motile spermatozoa), the incidence of TFF significantly increased when MSPPI was <10%, and the fertilization rate significantly decreased when MSPPI was <30%. We found that cumulative MSPPI correlated with the cumulative fertilization rate (Spearman correlation, 0.508, p<0.001). Regarding embryo development, we observed no significant differences in the rates of blastocyst development, chemical pregnancy, clinical pregnancy, or live birth among all groups. CONCLUSION: Our findings suggest that MSPPI is a viable indicator for split IVF-ICSI and ICSI. Taken together, by employing the MSPPI test in advance before IVF, ICSI, or split IVF-ICSI cycles, unnecessary split IVF-ICSI and ICSI may be avoided.
Blastocyst ; Embryonic Development ; Female ; Fertilization ; Fertilization in Vitro ; Incidence ; Insemination ; Live Birth ; Pregnancy ; Prospective Studies ; Sperm Injections, Intracytoplasmic* ; Spermatozoa*