The impact of severe oligozoospermia on morphokinetic embryo development in low-prognosis patients according to the Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number criteria: an analysis of 10,366 injected oocytes

Objective

To study whether severe male factor infertility (SMF), reflected by oligozoospermia, impacts embryo morphokinetic behavior in low-prognosis women as stratified by the Patient-Oriented Strategies Encompassing IndividualizeD Oocyte Number (POSEIDON) criteria.

Design

Cohort study.

Setting

Private university–affiliated in vitro fertilization center.

Patient(s)

A total of 10,366 injected oocytes from 2,272 women who underwent intracytoplasmic sperm injection cycles between March 2019 and April 2022.

Intervention(s)

Patients were divided into 8 groups according to the POSEIDON criteria (1, 2, 3, 4) and the presence or absence of SMF. A control group of normoresponder patients was included. Kinetic markers from the point of insemination were recorded in the EmbryoScope incubator.

Main Outcome Measure(s)

Morphokinetic milestones and intracytoplasmic sperm injection clinical outcomes.

Result(s)

Embryos from patients in the POSEIDON 1 group showed significantly slower timing to pronuclear appearance, timing to pronuclear fading (tPNf), timing to 2 (t2), 3 (t3), 4 (t4), 6 (t6), and 7 (t7) cells than those from the control group. Known Implantation Diagnosis Score ranking was significantly different between the SMF and non-SMF (nSMF) subgroups in both POSEIDON 1 as well as control groups. Embryos from patients in the POSEIDON 2 group showed significantly slower timing to pronuclear appearance, t4, t6, t7, timing to 8 cells (t8), and timing to morulae than those from the control group. Embryos in the POSEIDON 2 SMF subgroup took longer than those in the POSEIDON 2 nSMF subgroup and those in both control subgroups to achieve tPNf, t2, t3, timing to 5 cells (t5), timing to start blastulation, and timing to blastulation. Known Implantation Diagnosis Score ranking was significantly different between the SMF and nSMF subgroups in both POSEIDON 2 as well as control groups. Embryos from patients in the POSEIDON 3 group showed significantly slower t8 and duration of the second cell cycle (t3-t2) than those from the control group. Known Implantation Diagnosis Score ranking was significantly different across the subgroups. Embryos derived from patients in the POSEIDON 4 group showed significantly slower tPNf, t2, t3, t4, t5, t6, t7, t8, timing to complete t4-t3 synchronous divisions, and timing to complete t8-t5 synchronous divisions than those from the control group. Known Implantation Diagnosis Score ranking was significantly different between the SMF and nSMF subgroups in both POSEIDON 4 as well as control groups. Irrespective of sperm quality, clinical outcomes significantly improved in the control subgroups compared with those in the POSEIDON 2 and 4 subgroups.

Conclusion(s)

Embryos in the SMF groups presented lower Known Implantation Diagnosis Score ranking than those in the nSMF groups in both POSEIDON 1–4 and control groups, suggesting that cumulative differences result in worse morphokinetic development when the algorithm is used.