Complete embryo developmental arrest and its prognostic significance in in vitro fertilization

To identify the rate of repeated embryo arrest in the subsequent in vitro fertilization (IVF) cycle for those with prior complete embryo developmental arrest (EDA) in their index cycle.

Retrospective cohort study with exposure groups matched via propensity scoring (1:2 ratio).

All patients who underwent two consecutive ovarian stimulation cycles for IVF within a year, resulting in at least two or more 2-pronuclei embryos between January 2017 and April 2025.

Patients were categorized by the embryology outcomes of the index cycle: complete EDA group (0% blastocyst formation rate) and comparison group (one or more blastocysts cryopreserved).

Primary outcome measure was blastulation rate in the subsequent IVF cycle. Secondary outcomes included the total number of oocytes retrieved, total mature oocytes, total fertilized oocytes, total blastocysts, and the euploidy rate. Doubly robust estimation was employed with multivariable log-binomial regression models to test the association of complete EDA with blastulation outcomes in the matched sample.

Before matching, 501 and 3,412 patients were identified in the EDA and comparison groups, respectively. The EDA group was significantly older with fewer mature oocytes. Matching balanced these factors. After matching, multivariable analysis (444 with EDA and 815 without) found that a history of complete EDA remained significantly and independently associated with lower fertilization rates (76.6% ± 24.6% vs. 81.5% ± 21.1%, adjusted risk ratio [aRR]: 0.94, 95% confidence interval [CI]: 0.92-0.97), lower blastulation rates (33.1% ± 30.1% vs. 47.0% ± 31.3%, aRR 0.75, 95% CI 0.70-0.80), and a higher risk of no blastulation (33.6% vs. 17.9%, aRR 1.82, 95% CI 1.44-2.3). Euploidy rates per blastocyst cryopreserved were not affected by EDA history (45.5% ± 40.8% vs. 46.7% ± 39.1%, aRR: 0.97, 95% CI: 0.81-1.15). In those with prior complete EDA, altering the stimulation protocol or trigger type from the arrest cycle to the subsequent cycle did not significantly improve blastulation rates or reduce the risk of no blastulation compared with keeping the same protocol or trigger for both cycles.

A history of complete EDA was a significant predictor of poorer results in the subsequent cycle and alterations to the treatment protocol were not associated with improved outcomes.