Insemination by In Vitro Fertilization (IVF): validation of a short-incubation protocol

• Published in: Reproductive biomedicine online 2024-05, Vol.48, p.104039, Article 104039
• Main Authors: Schoemans, C., Krunic, M., Sterckx, J., Bosman, T., Jankovic, D., Van Landuyt, L., De Vos, A., Mateizel, I., Segers, I., Wouters, K., De Munck, N.
• Format: Article
• Language: English
• ISSN: 1472-6483
• DOI: 10.1016/j.rbmo.2024.104039

In conventional IVF (cIVF), extended exposure (16-20 hours) of oocytes to spermatozoa metabolic waste may negatively impact embryo development, emphasizing the importance of incubation time in the IVF procedure. We aimed to compare fertilization rates, embryo quality and utilization rates between short IVF (sIVF) incubation and cIVF as part of a validation study. The study was performed between October 2022-2023. sIVF incubation was performed and oocytes were denuded 6 hours later. Control patients underwent cIVF within the same study period, with denudation performed 16-20h post insemination. Fertilization rates, embryo quality and utilization rates were assessed and compared between the two groups. Regression analysis was performed considering age, age of partner, total COCs retrieved and number of previous cycles as potential confounders. Based on the time of oocyte retrieval, 24 cycles were included in sIVF (n=244 COCs) and 187 cycles in cIVF (n=1922 COCs). Patients were on average 34.1±4.2 and 32.3±4.8 years old, respectively. Fertilization rates per COC (52% and 53% respectively, p=0.742) and per mature oocyte (MII, 60% and 63% respectively, p=0.848) showed no significant differences. The incidence of abnormally fertilized oocytes (≥3 pronuclei) was significantly lower in sIVF (10% vs 13% respectively, p=0.040) when only mature oocytes were taken into account. Day 3 and day 5 rates of good quality embryos per fertilized oocyte (2PN) were comparable between sIVF and cIVF (day 3: 75% vs 77%, p=0.970; day 5: 28% vs 42%, p=0.174). No significant difference was found for utilization rates per COC, per MII, or per 2PN [19% vs 28% (p=0.450), 22% vs 33% (p=0.381), 37% vs 52% (p=0.173), respectively]. Linear regression analysis revealed no significant confounding effects on the tested variables. Heterogeneity and limited sample size are the main drawbacks of this study with a need for a prospective sibling oocyte study to further elucidate potential differences between sIVF and cIVF. To conclude, sIVF is comparable to cIVF in terms of fertilization rates, embryo quality and utilization rates. The lower rate of abnormally fertilized oocytes shows a potential advantage of a sIVF protocol.