Vaginal Infection in Pregnancy Is Associated with Amniotic Oxidative Stress: Insights from AOPP and MDA on Neonatal Outcomes

Amniotic oxidative stress in women with vaginal infection but no documented intra-amniotic infection has received little attention. In this prospective cohort study of 90 women undergoing elective cesarean delivery, 45 had symptomatic, culture- or Nugent-confirmed vaginal infection and 45 were asymptomatic controls. Amniotic fluid advanced oxidation protein products (AOPP) and malondialdehyde (MDA) were measured by commercial ELISA. Both were higher in the infection group (median 7.96 versus 5.77 ng/mL and 12.49 versus 7.73 nmol/mL, both p < 0.001), with lower cord blood pH (p = 0.003) and more frequent neonatal intensive care unit (NICU) admission (26.7% versus 4.4%, p = 0.007). AOPP was associated with NICU admission (area under the curve 0.917, 95% CI 0.777 to 0.999), although this rests on 14 events with thresholds derived and evaluated in the same sample. Elevations were largest in the bacterial vaginosis and aerobic bacterial subgroups, but the etiologies did not differ. Both kits were designed for serum and are not validated for amniotic fluid, and 16.7% of MDA measurements fell outside the calibration range, so the MDA results are semi-quantitative. Vaginal infection at cesarean delivery is associated with higher amniotic oxidative stress markers; these findings are exploratory and require external validation.