On the other hand, the rejection of O in favor of other factors in the final model did not exclude potential effect of the use of two doses of oxytocin on stillbirth since this effect was significant in all models even with the presence of both BO and O. This effect can be explained by the fact that piglets born late in the farrowing process were subjected to a longer period of distress and hypoxia, and at very late parturition even mild distress and hypoxia caused by the second oxytocin injection could lead to an increased risk of fetal death. This evidence concerns the gene OXT and Stillbirth.