Abstract
Study question
Does time between ejaculation and processing, and time between processing and insemination/injection affect fertilization rate (FR) and ongoing pregnancy rate (OPR) in IVF/ICSI treatments?
Summary answer
Increasing time between processing and insemination significantly decreased the OPR after IVF. FRs after IVF/ICSI and OPR after ICSI were not affected by different time-intervals.
What is known already
The choice for IVF or ICSI depends on semen quality, however, this doesn’t affect the outcome of IVF/ICSI treatments (Mariappen et al 2018). After ejaculation, the percentage of motile spermatozoa decreases progressively at a rate of about 10%/hour (Makler 1979). According to the ESHRE-guideline, semen should be processed within 1 hour after ejaculation. In our laboratory, a validation was performed that confirmed a decrease in sperm motility after ejaculation. During incubation at 37 °C after processing, the sample remained stable in incubation medium (unpublished data). Therefore, we analyzed the effect of handling time and incubation time with regard to IVF/ICSI outcomes.
Study design, size, duration
This retrospective data analysis examines the effect of time between ejaculation and processing using density-gradient centrifugation (handling time) and time between processing and insemination (IVF)/injection (ICSI) (incubation time) on the FR and OPR, irrespective of the initial semen quality. A total of 1488 oocyte pickups (844 IVF, 644 ICSI) were included from 1060 patients undergoing fertility treatment between 2017 and 2019. Oocyte pickups without oocytes, with oocyte vitrification, or with donor oocytes were excluded.
Participants/materials, setting, methods
Anonymized data were obtained from the laboratory database ProMISe. Handling time and incubation time of the semen incubated at 37 °C and 5% CO2 were analyzed in relation to the occurrence of TFF (Total Fertilization Failure), FR and OPR. Linear and logistic regression was performed in SPSS version 25. In case of significant association, the data were adjusted for potential confounders, such as woman’s age, semen quality before and after preparation, and number of oocytes.
Main results and the role of chance
This study shows that increasing the incubation time of the semen significantly reduced the OPR per ET in IVF treatments (from 30,8% within 3,5 hours to 24,1% after 6 hours) even after adjusting for the potential confouders. However, the OPR in ICSI treatments was not significantly affected by the incubation time (rather, there was an opposite trend). Also, the handling time of the semen did not significant effect the FR per OPU and the OPR per ET in IVF/ICSI treatments. The overall percentage of TFF was 3,5% and did not differ significantly between the IVF and ICSI treatments. Both handling time and incubation time did not have a significant effect on the occurrence of TFF. An explanation for the decrease in OPR in IVF treatments may be that increasing the incubation time at 37 °C reduces the sperm quality as the capacitation reaction takes place too early, energy levels are reduced, DNA damage increases, or vacuoles arise in the sperm heads (Thijssen et al 2014, Jackson et al 2010, Peer et al 2007). Incubation at room temperature and reduction of the insemination time may improve OPR.
Limitations, reasons for caution
Retrospective study limitations (bias), no data on DNA fragmentation, incubation of semen only at 37 °C after preparation.
Wider implications of the findings: Although it is recommended to produce semen at the IVF-department, our results show that an exception can be made, when production of a semen sample in a clinical setting is stressful, with no negative effect on the outcome. Furthermore, incubation-time at room temperature may have a positive effect on OPR.
Trial registration number
Not applicable
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