The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co-culture of embryos with human fibroblasts was evaluated with respect topregnancy rate and embryo development. Patients were included in the studyafter giving informed written consent. The IVF treatments were randomlyassigned by stratification of both age (<36 versus > or =36 years)and previous IVF attempts (yes versus no). After fertilization wasestablished, the zygotes were transferred to a 4-well dish with or withoutfibroblasts and cultured for 2 days. On the third day after ovum pick-up(OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos werescored and a maximum of three embryos was transferred. Supernumeraryembryos of good quality were cryopreserved. The design of this study was agroup sequential trial with the objective of detecting differences betweenpregnancy rates following IVF with conventional incubation or incubation inco-culture with fibroblasts. This design included one evaluation athalf-way data collection. In the study, 148 patients had an OPU, of whom 77were allocated to the co-culture group. There was no statisticallysignificant difference in pregnancy rate, cell number and embryo qualitybetween the two groups. The ongoing pregnancy rate per embryo transfer was27% in co-culture and 30% in the conventional culture group. Theimplantation rates per transferred embryo were 17 and 18% respectively.Using a multivariate logistic regression model for the probability ofongoing pregnancies, the odds ratio of co-culture, adjusted for age andprevious IVF attempts, was not statistically significant. In conclusion,co-culture with human fibroblasts does not contribute to an improvement ofembryo quality nor to a higher pregnancy rate after IVF in an unselectedgroup of patients.