GM-CSF does not rescue poor-quality embryos: secondary analysis of a randomized controlled trial

To evaluate implantation potential of cleavage-stage embryos cultured in medium containing 2 ng/ml granulocyte-macrophage colony-stimulating factor (GM-CSF) versus control medium, according to embryo morphological quality and then transferred on day 3.

Explorative secondary data analysis of a multicenter, randomized, placebo-controlled, double-blinded prospective study of 1149 couples with embryo transfer after IVF/ICSI. This analysis includes a subgroup of 422 subjects with either single-embryo transfer (SET, N = 286) or double-embryo transfer of two embryos with equivalent morphological quality (DET, N = 136). Implantation rate and live birth rate were assessed according to category of morphological embryo quality on day 3.

Culture with GM-CSF did not increase the implantation rate for embryos classified as poor quality. A trend towards greater benefit of GM-CSF on implantation and survival until live birth for top-quality embryos (TQEs) compared with poor-quality embryos was observed, although not statistically significant. For TQEs, the percentage of transferred embryos resulting in a live born baby was: 40.9 ± 5.3% (GM-CSF) versus 30.5 ± 4.6% (control) (P = 0.24; odds ratio [OR] 1.43, 95% confidence interval [CI] 0.79-2.59), and for embryos with less than 6 cells at day 3 this same rate was: 7.4 ± 3.3% (GM-CSF) versus 12.0 ± 4.0% (control) (P = 0.26; OR 0.53, 95% CI 0.17-1.61).

This exploratory analysis is consistent with GM-CSF protecting morphologically normal embryos from culture-induced stress and does not support an effect of GM-CSF in rescuing poor-quality embryos. ClinicalTrials.gov identifier: NCT00565747.