Human embryos secrete microRNAs into culture media--a potential biomarker for implantation.

Objective: To determine whether human blastocysts secrete microRNA (miRNAs) into culture media and whether these reflect embryonic ploidy status and can predict in vitro fertilization (IVF) outcomes.

Design: Experimental study of human embryos and IVF culture media.

Setting: Academic IVF program.