The Quality of Human Embryo Growth is Improved when Embryos Are Cultured in Groups Rather Than Separately

Objective: To determine the effect of culturing human embryos in groups on cleavage rates, morphology grades, and embryo scores when compared with embryos cultured singly.

Design: Prospective.

Setting: The IVF-ET program of the Pennsylvania State University, Department of Obstetrics and Gynecology, Hershey Medical Center, Hershey, Pennsylvania.

Patients: Fifty-five infertile women who each had at least five zygotes underwent IVF-ET.

Interventions: Zygotes from each patient were allocated to be cultured singly and in groups.

Main Outcome Measures: Cleavage rate, morphology grade, and embryo score.

Results: Grouping embryos significantly enhanced cleavage rates and embryo scores but not morphology grade as compared with embryos grown singly. Additionally, the size of the groups correlated positively with cell number and embryo score but not the morphology grade.

Conclusion: Culturing human embryos in groups enhances the quality of their growth by increasing the cleavage rates and embryo scores. Because pregnancy rates are improved by transferring embryos with higher embryo scores, coculturing human embryos may be a way of enhancing pregnancy rates.