Objective As a first step towards evaluating the role of oxidative stress in the process of labour, we tested whether term labour is associated with increased oxidisibility of maternal serum lipids.
Design A controlled prospective study.
Setting Tertiary care centre.
Population Twenty healthy women in active labour and 20 healthy pregnant women not in labour (controls) matched for maternal and gestational age.
Methods Venous blood was drawn from women in both groups. Serum levels of lipid peroxidation products and the kinetics of copper-induced oxidation ex vivo were monitored spectroscopically at 37°C by continuous recording of absorbance at 245 nm.
Main outcome measures Oxidative stress parameters.
Results The initial optical density (OD) at 245 nm, attributed to preformed dienic hydroperoxides and 7-keto-cholesterol (main products of lipid peroxidation), was higher in the labouring group than in the controls (1.30 ± 0.11 vs 1.18 ± 0.09, OD 245 nm, respectively, P < 0.001). The lag phase, reflecting resistance of serum lipids to oxidation, was significantly shorter in the labouring group than in the controls (43.2 ± 1.4 vs 56.2 ± 4.7 min, respectively, P= 0.01).
Conclusion High levels of serum hydroperoxides and decreased resistance of serum lipids to copper-induced peroxidation ex vivo suggest labour to be associated with high oxidative stress. Whether oxidative stress is involved in initiating the labour process or is consequent awaits further studies.