Blastocyst collapse is not an independent predictor of reduced live birth: a time-lapse study.

OBJECTIVE: To ascertain the rate of blastocyst collapse observed by time-lapse monitoring in a retrospective cohort of unselected infertile patients undergoing single blastocyst transfer and to determine its association with live birth.
DESIGN: Blastocyst collapse and morphokinetic variables were scored according to previously published criteria. The association between blastocyst collapse and live birth was evaluated by a multivariate logistic regression analysis including morphokinetic variables and other confounders.
SETTING: Private infertility clinic. PATIENT(S): Patients who underwent 277 consecutive single blastocyst transfers (mean age, 38.4 ± 3.9 years; range, 28-47 years) after minimal ovarian stimulation. INTERVENTION(S): Minimal ovarian stimulation, prolonged embryo culture in time-lapse monitoring incubator, elective vitrification with subsequent vitrified-warmed single blastocyst transfer. MAIN OUTCOME MEASURE(S): Live birth rate per single blastocyst transfer in different blastocyst collapse groups (no, single, multiple collapses). RESULT(S): No, single, or multiple blastocyst collapses occurred in 54% (150/277), 22% (61/277), and 24% (66/277) of the cohort, respectively. In the multiple collapse group on average 2.9 contractions were seen (range, 2-9 contractions). Live birth rate decreased progressively between blastocyst collapse groups (36%, 31%, 14%); significantly lower if multiple collapses occurred. In a multivariate analysis, however, blastocyst collapse was not found to be a significant predictor and was confounded by stronger predictors such as morphokinetic variables t2, texpB2, and female age. CONCLUSION(S): Blastocyst collapse pattern should not be evaluated alone without taking into account morphokinetic variables that are stronger predictors of reproductive outcome.