Humid versus dry incubator: a prospective, randomized, controlled trial

Abstract

Objective: To evaluate the efficacy of a dry versus humidified incubator on human embryo development ex vivo.

Design: Prospective, double-blind, randomized, controlled trial.

Setting: Private fertility centers.

Patient(s): A total of 297 women undergoing in vitro fertilization randomized into two groups.

Intervention(s): From days 0 to day 5 or 6 of culture, intervention group embryos exposed to dry culture and control group embryos exposed to humidified culture.

Main outcome measure(s): Subsequent ongoing pregnancy rate.

Result(s): After transfer of embryos, there were statistically significantly lower rates of clinical and ongoing pregnancy in the dry culture arm than in the humidified culture arm (odds ratio [OR] 0.57; 95% confidence interval [CI], 0.36-0.91; versus OR 0.54; 95% CI, 0.34-0.85). On day 3 of culture, embryo quality and compaction were lower in the dry culture group (OR 0.38; 95% CI, 0.32-0.45) than in the group exposed to humidified culture (OR 0.23; 95% CI, 0.19-0.27). On day 5 of culture, embryos in dry culture had a lower rate of blastocyst formation (OR 0.39; 95% CI, 0.33-0.46), quality (OR 0.34; 95% CI, 0.29-0.40), and cryopreservation (OR 0.41; 95% CI, 0.35-0.48).

Conclusion(s): In this study, human embryos cultivated ex vivo in a dry incubator had statistically significantly decreased implantation and clinical and ongoing pregnancy rates. Our findings indicate the need for larger multicenter, randomized, controlled trials.

Clinical trial registration number: NCT01695096.

Keywords: Embryo culture; incubator humidity; in vitro fertilization laboratory.

Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.