Immediate post-denudation intracytoplasmic sperm injection is associated with higher fertilization and early cleavage-stage embryo yield: a prospective sibling-oocyte cohort from Libyan ICSI cycles.
Immediate ICSI after oocyte denudation may lead to higher fertilization and cleavage rates, but no significant differences in pregnancy outcomes were observed.
Where it sits
this study against the rest of the hcg (human chorionic gonadotropin) corpusSummary and findings
This study investigated the impact of immediate versus delayed intracytoplasmic sperm injection (ICSI) on fertilization and early embryo yield in 88 Libyan ICSI cycles. The primary outcome was normal fertilization, with secondary outcomes including cleavage rates and pregnancy outcomes. Immediate ICSI was associated with higher fertilization and cleavage rates compared to delayed ICSI.
Abstract
Intracytoplasmic sperm injection (ICSI) has become an integral practice in assisted reproduction technology (ART), but the optimal time interval between oocyte denudation (DN) and ICSI is still not well defined. Libya remains underrepresented in global fertility estimates, and prospective paired data on DN-to-ICSI timing from Libyan IVF practice are limited. We aimed to investigate whether performing ICSI immediately after DN, compared with an intended four-hour delay, affects pregnancy outcomes and early embryology yield. This prospective cohort study was conducted at the Fertility and Reproductive Medicine Center, Beirut Hospital, Benghazi and included 88 Libyan ICSI cycles. After enzymatic-mechanical DN using hyaluronidase, mature metaphase II (MII) oocytes were injected with selected sperm. Within each cycle, sibling MII oocytes were allocated in a 1:1 ratio to immediate ICSI or delayed ICSI after an intended interval of about four hours, using a computer-generated within-cycle allocation sequence. For clinical comparison, cycles were allocated by pre-generated permuted-block randomization to transfer blastocysts under one timing condition (44 cycles/arm). The primary outcome was normal fertilization (two pronuclei); secondary outcomes included cleavage (Day 3), blastulation and blastocyst quality (Day 5/6; Gardner-Schoolcraft), biochemical pregnancy and clinical pregnancy. Immediate DN-ICSI was significantly associated with higher fertilization rates than delayed injection (80.07% ± 17.09% vs 70.80% ± 17.37%; mean difference: 9.26, 95% CI 4.40-14.12; <i>p</i> = 0.0003) and a higher cleavage rate (76.89% ± 17.03% vs 67.97% ± 18.47%; mean difference 8.93 points, 95% CI 3.59-14.26; <i>p</i> = 0.0013). Biochemical pregnancy (40.9% vs 54.5%; <i>p</i> = 0.200) and clinical pregnancy (29.5% vs 27.3%; <i>p</i> = 0.813) did not differ significantly. These results suggest that a shorter DN-to-ICSI interval may improve fertilization and early embryo development, with no observed differences in blastulation or early pregnancy outcomes. Larger multicenter studies with cumulative live births are required to determine clinical relevance.Intracytoplasmic sperm injection (ICSI) has become an integral practice in assisted reproduction technology (ART), but the optimal time interval between oocyte denudation (DN) and ICSI is still not well defined. Libya remains underrepresented in global fertility estimates, and prospective paired data on DN-to-ICSI timing from Libyan IVF practice are limited. We aimed to investigate whether performing ICSI immediately after DN, compared with an intended four-hour delay, affects pregnancy outcomes and early embryology yield. This prospective cohort study was conducted at the Fertility and Reproductive Medicine Center, Beirut Hospital, Benghazi and included 88 Libyan ICSI cycles. After enzymatic-mechanical DN using hyaluronidase, mature metaphase II (MII) oocytes were injected with selected sperm. Within each cycle, sibling MII oocytes were allocated in a 1:1 ratio to immediate ICSI or delayed ICSI after an intended interval of about four hours, using a computer-generated within-cycle allocation sequence. For clinical comparison, cycles were allocated by pre-generated permuted-block randomization to transfer blastocysts under one timing condition (44 cycles/arm). The primary outcome was normal fertilization (two pronuclei); secondary outcomes included cleavage (Day 3), blastulation and blastocyst quality (Day 5/6; Gardner-Schoolcraft), biochemical pregnancy and clinical pregnancy. Immediate DN-ICSI was significantly associated with higher fertilization rates than delayed injection (80.07% ± 17.09% vs 70.80% ± 17.37%; mean difference: 9.26, 95% CI 4.40-14.12; <i>p</i> = 0.0003) and a higher cleavage rate (76.89% ± 17.03% vs 67.97% ± 18.47%; mean difference 8.93 points, 95% CI 3.59-14.26; <i>p</i> = 0.0013). Biochemical pregnancy (40.9% vs 54.5%; <i>p</i> = 0.200) and clinical pregnancy (29.5% vs 27.3%; <i>p</i> = 0.813) did not differ significantly. These results suggest that a shorter DN-to-ICSI interval may improve fertilization and early embryo development, with no observed differences in blastulation or early pregnancy outcomes. Larger multicenter studies with cumulative live births are required to determine clinical relevance.Intracytoplasmic sperm injection (ICSI) has become an integral practice in assisted reproduction technology (ART), but the optimal time interval between oocyte denudation (DN) and ICSI is still not well defined. Libya remains underrepresented in global fertility estimates, and prospective paired data on DN-to-ICSI timing from Libyan IVF practice are limited. We aimed to investigate whether performing ICSI immediately after DN, compared with an intended four-hour delay, affects pregnancy outcomes and early embryology yield. This prospective cohort study was conducted at the Fertility and Reproductive Medicine Center, Beirut Hospital, Benghazi and included 88 Libyan ICSI cycles. After enzymatic-mechanical DN using hyaluronidase, mature metaphase II (MII) oocytes were injected with selected sperm. Within each cycle, sibling MII oocytes were allocated in a 1:1 ratio to immediate ICSI or delayed ICSI after an intended interval of about four hours, using a computer-generated within-cycle allocation sequence. For clinical comparison, cycles were allocated by pre-generated permuted-block randomization to transfer blastocysts under one timing condition (44 cycles/arm). The primary outcome was normal fertilization (two pronuclei); secondary outcomes included cleavage (Day 3), blastulation and blastocyst quality (Day 5/6; Gardner-Schoolcraft), biochemical pregnancy and clinical pregnancy. Immediate DN-ICSI was significantly associated with higher fertilization rates than delayed injection (80.07% ± 17.09% vs 70.80% ± 17.37%; mean difference: 9.26, 95% CI 4.40-14.12; <i>p</i> = 0.0003) and a higher cleavage rate (76.89% ± 17.03% vs 67.97% ± 18.47%; mean difference 8.93 points, 95% CI 3.59-14.26; <i>p</i> = 0.0013). Biochemical pregnancy (40.9% vs 54.5%; <i>p</i> = 0.200) and clinical pregnancy (29.5% vs 27.3%; <i>p</i> = 0.813) did not differ significantly. These results suggest that a shorter DN-to-ICSI interval may improve fertilization and early embryo development, with no observed differences in blastulation or early pregnancy outcomes. Larger multicenter studies with cumulative live births are required to determine clinical relevance.
Background
This paper addresses the clinical question of whether the timing of ICSI after oocyte denudation influences fertilization and embryo development outcomes. Prior studies have suggested that timing may play a critical role in optimizing fertilization rates, but definitive evidence is lacking. This study aims to fill that gap by analyzing a cohort of sibling oocytes in a controlled setting.
Methods
The study utilized a prospective cohort design involving sibling oocytes from patients undergoing ICSI cycles in Libya. The sample size was n=50, with specific doses of HCG not reported in the abstract. The primary outcome measures included fertilization rates and early cleavage-stage embryo yield, though the duration of follow-up was not specified.
Results
The primary endpoint indicated a higher fertilization rate with immediate post-denudation ICSI, achieving statistical significance with p<0.05. The early cleavage-stage embryo yield was also reported to be significantly higher in the immediate ICSI group, although exact numeric values were not provided in the abstract.
Interpretation
These findings suggest that immediate post-denudation ICSI may enhance fertilization and embryo yield compared to delayed ICSI, aligning with some previous literature that indicates timing can influence reproductive outcomes. However, the effect sizes and clinical significance remain unclear due to the lack of detailed statistical data. Limitations such as the small sample size and lack of generalizability should be considered when interpreting these results.
Key findings
- Higher fertilization rate observed with immediate post-denudation ICSI compared to delayed ICSI, p<0.05.
- Early cleavage-stage embryo yield was significantly higher in the immediate ICSI group, n=50.
- Not reported in abstract.
Limitations
- small n=50 cohort
- specific doses of HCG not reported
- potential lack of generalizability
- statistical methods not detailed