Abstract

Parturition is simply described as the process by which the fetus is expelled from the uterus to the extrauterine environment. However complex interactions of the fetal hypothalamic–pituitary–adrenal axis, hormonal (oxytocin, estrogen, progesterone relaxin), mechanical (uterine stretch), electrical (gap junctions) and inflammatory (cytokines) factors have important roles in the initiation and maintenance of labour.1

We aim to further investigate the similarities and differences in the expression of prolabour genes and cytokines in the lower myometrial segment in labour versus no labour.

Women were recruited in four defined groups (n=12): preterm not in labour (24-36 weeks), term not in labour (>37 weeks), term early labour (3-4 contractions in 10 minutes and <3cm dilated) and term established labour (3-4 contractions in 10 minutes and ≥3cm dilated). Myometrial biopsies collected from the upper aspect of the lower segment incision at the time of caesarean section for medical reasons and immediately flash frozen at -80°C. There was no evidence of infection, abruption, slow progess of labour and syntocinon administration.

RNA was extracted using the RNAeasy mini kit from Qiagen Ltd. 1.0 mg was reverse transcribed and quantitative PCR was performed to examine the expression of COX-2 and IL-8 with GAPDH as a housekeeping gene.2 COX-2 expression was found to be significantly increased in labour compared to no labour.

We have therefore shown that labour is a proinflammatory process using myometrial samples from a well defined group where we have eliminated confounding factors.