Circulating Cell-Free Mitochondrial DNA as a Novel Biomarker for Intra-Amniotic Infection in Obstetrics: A Pilot Trial

Abstract

Background/Objectives: Intra-amniotic infection (IAI) is a rare but serious condition with potential complications such as preterm labor and intrauterine fetal death. Diagnosing IAI is challenging due to varied clinical signs. Oxidative stress and mitochondrial dysfunction have been hypothesized to evolve around IAI. This study focused on measuring circulating mtDNA levels, a proposed biomarker for mitochondrial dysfunction, in maternal serum and placenta of women with confirmed IAI and healthy controls. Methods: 12 women with confirmed IAI (IAI group) were enrolled following premature preterm rupture of the membranes (PPROM) and compared to 21 healthy women (control group). Maternal blood was obtained two weeks pre-partum and peripartum; furthermore, postpartum placental blood was taken. In the IAI group, maternal blood was taken once weekly until delivery as well as peripartum, as was placental blood. Circulating cell-free mtDNA was quantified by real-time quantitative PCR. Results: Upon admission, in the IAI group, mean plasma mtDNA levels were 735.8 fg/μL compared to 134.0 fg/μL in the control group (p < 0.05). After delivery, in the IAI group, mean mtDNA levels in the placenta were 3010 fg/μL versus 652.4 fg/μL (p < 0.05). Conclusions: Circulating cell-free mtDNA could serve as a valuable biomarker for IAI prediction and diagnosis. Future research should establish reference values for sensitivity in predicting IAI.