Incidence of abnormal cleavage patterns in conventional IVF versus ICSI: a retrospective analysis of 125,570 normally fertilised embryos.

RESEARCH QUESTION: Do the different fertilisation methods of conventional in vitro fertilisation (cIVF) or intracytoplasmic sperm injection (ICSI) affect abnormal cleavage (ABNCL) of early embryos?

DESIGN

A retrospective cohort study on 125,570 normally fertilised embryos from a large reproductive medicine centre. Normal cleavage (NC) and ABNCL embryos in the entire cohort were identified. Multivariable logistic regression with generalised estimating equations (GEE), stratified analysis and inverse probability weighting (IPW) were used to assess the incidence of ABNCL events in cIVF- and ICSI-derived embryos.

RESULTS

GEE analysis adjusted for multiple variables showed that the incidence of ABNCL was significantly higher in ICSI than cIVF (52.14 % vs 40.82 %, adjusted odds ratio [aOR] = 1.674, 95% confidence interval [CI]: 1.590-1.762, P < 0.001). Among the different female ages and ovarian stimulation regimens, higher incidences of ABNCL embryos were observed in ICSI compared with cIVF, and stratified analysis of sperm parameters showed that the incidence of ABNCL was significantly higher in ICSI than cIVF for the normozoospermia, mildly abnormal semen, and multiple abnormal semen groups (all P < 0.05).

CONCLUSIONS

Embryos derived from ICSI were more prone to ABNCL than those derived from cIVF, and this association persists across female ages, different stimulation regimens and sperm parameter subgroups. Although semen parameters may modulate this risk, the consistent trend suggests that the ICSI procedure may be associated with an increased incidence of ABNCL.