Towards a point of care approach for intra-amniotic infection or early delivery using minimally invasive prediction models in women with preterm labor.

Abstract

Among women with preterm labor and intact membranes, those with intra-amniotic infection or inflammation represent the highest risk group of spontaneous delivery and worse adverse outcome. Identification of this group requires amniocentesis, which is perceived as too invasive by both patients and physicians. This study aimed to develop a minimally invasive prediction model for intra-amniotic infection or early delivery, thereby better stratifying patients (low or high-risk) and rationalizing the use of amniocentesis limiting the indications to the highest-risk group of spontaneous preterm delivery. We performed external validation of 4 prediction models using data from 2022-2024 of women diagnosed with preterm labor below 34 weeks admitted to the Hospital Clinic, Hospital Sant Joan de Déu, and the Hospital Vall Hebron in Barcelona (Spain), and the Hradec Kralove University Hospital, in Kradec Kralove (Czech Republic), who underwent amniocentesis to rule in/out intra-amniotic infection or inflammation. Different prediction models, including ultrasound (US) transvaginal cervical length, serum C-reactive protein (CRP), vaginal IL-6, vaginal pH, vaginal lactic acid, and vaginal Lactobacillus genus, were validated in these patients. Diagnostic performance was done in 114 women with PTL below 34 weeks, 42 (36.8%) of whom had intra-amniotic infection or spontaneous delivery within 7 days. The areas under the curve (AUC) of the different models ranged from ranging from 84 (95% confidence interval (CI) 78.8-89.2%) to 89.9% (88.4-91.4%), sensitivities ranging from 78.6 (33/42) to 90.5% (38/42). and specificities from 70.8% (51/72) to 84.7% (61/72). The most feasible and efficient model was formed by combining US cervical length, serum CRP and vaginal IL-6, showing an AUC of 84% with a sensitivity of 78.6% (33/42), specificity of 84.7% (61/72), positive predictive value of 75% (33/44), and negative predictive value of 87.1% (61/70). We developed minimally invasive models to screen women at high risk of intra-amniotic infection or early delivery and guide the selective use of amniocentesis, thereby improving both antenatal counseling and the clinical management of high-risk patients.