Elevated Amniotic Fluid 8-Iso-Prostaglandin F2α Reveals Intrauterine Oxidative Stress in Fetuses with Congenital Heart Disease: A Prospective Case-Control Study.

Advances in prenatal diagnosis have improved the perinatal management of congenital heart disease (CHD). However postnatal comorbidities still persist due to multifactorial causes, which limits prenatal prediction of individual outcomes. Oxidative stress (OS), particularly lipid peroxidation, has been suggested to play a role in the development and progression of CHD, with 8-iso-prostaglandin F2α (8-iso-PGF2α) serving as a biomarker of oxidative injury. This prospective case-control study aimed to evaluate OS in fetuses with isolated major CHD by comparing amniotic fluid (AF) 8-iso-PGF2α concentrations with controls. A total of 123 fetuses (83 CHD, 40 controls) were included at a tertiary CHD referral center. CHD cases were subclassified according to anatomical type and expected fetal brain perfusion under placental circulation. Controls were gestational age-matched pregnancies undergoing amniocentesis for indications unlikely to affect OS. All pregnant women underwent standardized fetal biometry, Doppler assessment, and detailed echocardiography. AF samples were obtained by amniocentesis and analyzed for free 8-iso-PGF2α using a competitive ELISA, with values normalized to creatinine. Clinical, obstetric, and Doppler characteristics were comparable between groups. CHD fetuses showed significantly higher AF 8-iso-PGF2α concentrations than controls (2849 ± 1377 vs. 2088 ± 1087 ng/mg Cr, p = < 0.001), and remained significant after adjustment for GA, smoking status, diabetes and maternal age and body mass index (BMI). No consistent differences were observed across anatomical or hemodynamic CHD subgroups. These findings provide the first intrauterine evidence of increased lipid peroxidation in fetuses with CHD as reflected by elevated amniotic fluid 8-iso-PGF2α concentrations.