Exploratory observational study of the association between bacterial L-form detection and intrauterine infection in pregnant women with placenta previa and bleeding

Objective This study aimed to conduct an exploratory observational analysis to assess the association between bacterial L-form detection and intrauterine infection in pregnant women with placenta previa and bleeding, and to describe its potential relationship with maternal and fetal outcomes. Methods A total of 120 patients with placenta previa and bleeding were enrolled and divided into an L-form positive group ( n = 80) and an L-form negative group ( n = 40). The L-form positive group was further subdivided into patients with positive detection at admission ( n = 40) and before surgery ( n = 40). Maternal peripheral blood, vaginal secretions, placental tissue, umbilical cord tissue, neonatal umbilical cord blood, and neonatal peripheral blood were collected for bacterial L-form culture using hypertonic osmoprotective media. Contamination control procedures, parallel negative controls, duplicate inoculation, and predefined quality control procedures were applied throughout culture and identification. Clinical data and placental pathology were analyzed, and unadjusted odds ratios with 95% confidence intervals were calculated as descriptive measures of association. Results The L-form positive group had higher rates of multiple miscarriages (unadjusted OR = 2.67, 95% CI: 1.10–6.47), uterine cavity procedures (unadjusted OR=2.39, 95% CI: 1.10–5.18), and previous cesarean sections (unadjusted OR = 2.68, 95% CI: 1.07–6.73) than the L-form negative group. This group also showed lower gestational age and birth weight, together with higher rates of neonatal pneumonia (32.5% vs. 7.5%, unadjusted OR = 5.93, 95% CI: 1.67–21.04), chorioamnionitis (35.0% vs. 10.0%, unadjusted OR = 4.85, 95% CI: 1.57–14.95), and neonatal antibiotic use (40.0% vs. 12.5%, unadjusted OR = 4.67, 95% CI: 1.67–13.04). Exploratory susceptibility testing suggested low sensitivity to cell wall-active antibiotics and relatively higher sensitivity to polymyxin, rifampin, protein synthesis inhibitors, and cephalosporins. L-form detection in umbilical cord blood and neonatal peripheral blood was more frequent in the L-form positive group, and bacterial L-form detection showed descriptive correlations with lower gestational age, lower birth weight, pneumonia, neonatal mortality, and more severe chorioamnionitis. Conclusion In this exploratory observational study, bacterial L-form detection was associated with markers of intrauterine infection in pregnant women with placenta previa and bleeding. These findings should be interpreted cautiously because the analyses were unadjusted and the microbiological workflow remains exploratory.