[Effects of artificial shrinkage prior to vitrification in a closed system: a randomized controlled trial]

Abstract

Objective: To evaluate the effect of induced blastocoele shrinkage before vitrification in a closed carrier device.

Patients and methods: Prior to vitrification, blastocyst cavity was artificially shrinked by laser pulse or not treated according to a 2:1 randomized procedure. A total of 185 warming cycles from April 2011 to March 2013 have been analyzed. Clinical pregnancy rate and survival rate were compared between the two groups. The mean (±SD) women age was 33.5±5.7 years for both groups.

Results: The pregnancy rate in the group with artificial reduction of the cavity was higher ([32/67] 47.7%) than in the control group but not significantly ([43/113] 38%). The survival rate in the artificial shrinkage group was significantly higher compared with the control group : 99% (102/103) and 91.8% (168/183) respectively (P=0.01).

Discussion and conclusion: This study reveals that artificial shrinkage of blastocoelic cavity by laser pulse before vitrification in a closed carrier device improves survival rate after warming.

Keywords: Artificial shrinkage; Blastocoele; Blastocyst; Blastocystes; Blastocèle; Closed system; Collapsing; Réduction artificielle cavité; Système fermé; Vitrification.