Relative Morphokinetics Assessed by Time-Lapse Imaging Are Altered in Embryos From Patients With Endometriosis

Time-lapse technology allows almost continuous noninvasive assessment of embryonic development. It was shown previously that relative kinetics defining cleavage synchronicity are better predictors of blastocyst quality than absolute time points. This study aims to compare relative kinetics in embryos from patients with and without endometriosis.

Time-lapse data were collected retrospectively from 596 patients undergoing infertility treatment for in vitro fertilization from January 2011 to July 2016. Four hundred twenty-eight patients with confounding comorbidities (ie, polycystic ovary syndrome, pathological spermiogram in the included cycle, numerical/structural genetic abnormalities, preimplantation genetic screening performed) or incomplete data sets were excluded. Of the 168 included patients, 72 (42.9%) had endometriosis. Indications for in vitro fertilization of controls were tubal factor, unexplained infertility, or prolonged infertility. Relative kinetics were calculated as defined previously: cleavage synchronicity (CS)2-8=((t3-t2) + (t5-t4))/(t8-t2), CS4-8=(t8-t5)/(t8-t4), CS2-4=(t4-t3)/(t4-t2), DNA replication time ratio (DR)=(t3-t2)/(t5-t3). In women with more than one embryo, the median time was analyzed.

Median age, body mass index, smoking status, and AMH levels were similar in both groups. Embryos from patients with endometriosis showed poorer relative kinetics. The relative time CS2-8 was decreased in embryos from patients with endometriosis (0.7 [0.0-0.93] vs 0.8 [0.0-0.94], P < .05) and CS4-8 was increased (0.4 [0.0-1.0] vs 0.3 [0.0-1.0], P < .05). The less powerful diagnostic relative kinetic parameters (CS2-4 and DR) were not significantly different.

Embryos from patients with endometriosis presented with altered relative kinetics suggesting poorer embryo quality. These findings support recently published data demonstrating reduced oocyte quality in patients with endometriosis which is one possible explanation for their poor response to fertility treatment.