O-208 Use of epididymal spermatozoa in in vitro fertilization cycles impacts the morphokinetics of embryos cultured in a time-lapse imaging incubator system
Authors: Borges Junior E , Setti A , Braga D , Provenza R , Guilherme P , Iaconelli A. 
Published: June 2022

Abstract

Study question
Does sperm origin impact embryo morphokinetics (the moments at which an embryo reaches a developmental milestone) and clinical outcomes of intracytoplasmic sperm injection (ICSI) cycles?

Summary answer
The use of epididymal sperm correlates with late cell cleavages, and higher multinucleation and abnormal cleavage rates compared to those from men without infertility factor.

What is known already
ICSI with sperm surgically retrieved from the epididymis (PESA) dramatically altered the pregnancy prognosis in couples with severe male factor infertility, including obstructive azoospermia. The integration of time-lapse imaging (TLI) into the in vitro fertilization (IVF) laboratory allowed for an in-depth analysis of embryonic development. However, the impact of the use of epididymal sperm on embryonic morphokinetics has been poorly studied. We hypothesized that factors related to sperm origin may interfere with the speed and pattern of cell divisions.

Study design, size, duration
Women undergoing ICSI with epididymal sperm between Jan/2019 and Dec/2020 in a private university-affiliated IVF center were included (PESA group, n = 32 cycles/276 embryos). A matching was performed to form two groups of women undergoing ICSI using ejaculated sperm from partners with idiopathic male factor infertility (IMF group, n = 32 cycles/284 embryos) or without male factor infertility (Control group, n = 32 cycles/246 embryos). Generalized linear models followed by Bonferroni post hoc were used to compare morphokinetics between groups.

Participants/materials, setting, methods
Embryos were cultured in the EmbryoScope incubator, which recorded the following kinetic markers: timing to pronuclei appearance and fading (tPNa and tPNf), two (t2), three (t3), four (t4), five (t5), six (t6), seven (t7), and eight cells (t8), morulae (tM), start of blastulation (tSB) and blastulation (tB). Durations of second and third cell cycles (cc2 and cc3) and timing to complete synchronous divisions s1, s2, and s3 were calculated. The KIDScore ranking was recorded.

Main results and the role of chance
Embryos derived from epididymal sperm showed significantly slower divisions compared to those from ejaculated sperm (Table 1). The KIDScore rank was significantly lower for embryos deriving from epididymal sperm (3,1 ± 0.2) compared to those deriving from ejaculated sperm from IMF and control groups (5.4 ± 0.1 and 5.6 ± 0.2, p &lt; 0.001, respectively). The incidence of multinucleation was significantly higher in embryos deriving from epididymal sperm (23.2%) compared to those deriving from ejaculated sperm from IMF and control groups (2.8% and 3.7%, p &lt; 0.001, respectively). The incidence of abnormal cleavage patterns (direct or reverse) was significantly higher in embryos deriving from epididymal sperm (11.1%) compared to those deriving from ejaculated sperm from control group (4.3%, p = 0.001). Similar clinical outcomes were observed between the groups.

Limitations, reasons for caution
Retrospective nature of this study and the small sample size may be a reason for caution.

Wider implications of the findings
The use of epididymal sperm for ICSI correlates with delayed cell cleavage, and increased incidences of multinucleation and abnormal cleavage patterns. This finding highlights the importance of TLI for the identification and de-selection of slow-growing embryos for transfer, in ICSI cycles with surgical sperm retrieval.

Trial registration number
not applicable