Gene expression profile in labouring and non-labouring human placenta near term

The duration of pregnancy and initiation of labour are thought to be controlled by fetal, maternal and placental factors. The aim of this study was to investigate whether labour influences gene expression in placenta near term. Placental samples were obtained from 27 women after vaginal delivery (labouring) and 17 women after elective Caesarean section (non-labouring). All women were Caucasian and had uncomplicated pregnancies. For global gene expression analysis, 17 human oligo-arrays were used, representing 24 650 genes each. An empirical Bayes analysis was applied in order to find differentially expressed genes. About 8000 genes that were represented on the arrays met our quality criteria. Ninety two genes were down-regulated and 94 genes were up-regulated in labouring placentas compared to non-labouring placentas. However, none of these was differentially expressed at a significant level (>2.5-fold change and a P-value of <0.01). We conclude that gene expression in near term human placenta is not significantly altered by labour.