Objective: To determine the levels of 8-isoprostane (8-IP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine and in amniotic fluid (AF) of pregnant women and to assess the correlation between oxidative status in the maternal and fetal compartment in the second trimester of pregnancy.
Methods: One hundred and forty-six women with singleton pregnancies, undergoing amniocentesis at the Department of Obstetrics and Gynaecology at the University Medical Centre Ljubljana, were prospectively enrolled. AF and maternal urine were collected in the second trimester of pregnancy. Paired urinary and AF 8-IP and 8-OHdG were measured and evaluated cross-sectionally.
Results: 8-IP and 8-OHdG concentrations were higher in maternal urine compared to AF and the ratios were 47:1 and 50:1, respectively. AF 8-OHdG was very low and in 74% was below the limit of detection (LOD). We found a positive correlation between 8-IP in maternal and fetal compartment (ρ=0.217, P=0.008), which stayed unchanged also after adjustment for possible confounding factors.
Conclusions: Oxidative damage to lipids and DNA is also a part of physiologic processes during healthy pregnancy. 8-IP and 8-OHdG are constantly present in urine and AF. A weak positive correlation between maternal and fetal unit suggests a weak reflection of fetal oxidative status in maternal urine in the mid-trimester.
Keywords: Amniotic fluid; mid-trimester; oxidative stress; pregnancy; urine.