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The following is a summary of “A multisite study to develop and validate first trimester, circulating microparticle biomarkers for tiered risk stratification of spontaneous preterm birth in nulliparas,” published in the March 2025 issue of American Journal of Obstetrics & Gynecology by Rosenblatt et al. 

The background emphasized that progress in the early prediction of spontaneous preterm birth (sPTB) has been limited, prompting the exploration of circulating microparticles (CMP) as potential novel biomarkers.  

Researchers conducted a retrospective study to evaluate a first-trimester 7-marker CMP-derived protein assay as an in vitro diagnostic multivariate index assay (IVDMIA) for stratifying sPTB risk.  

They analyzed a validated set of CMP protein biomarkers using mass spectrometry assays within a nested case-control design in a subset from the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b). Plasma samples collected between 9 and 13 weeks of gestation were assessed through an IVDMIA to predict  sPTB risk. The IVDMIA stratified individuals into 3 risk categories: low risk (LR), moderate risk (MR), and high risk (HR). Performance validation on an independent set confirmed its accuracy in risk classification.  

The results showed that samples from 400 individuals in the nuMoM2b cohort were analyzed, including 160 who delivered before 37 weeks and 240 who delivered at term. Monte Carlo simulation, adjusted for actual weekly sPTB incidence rates, revealed significant differences in time-to-birth among risk groups (P <.0001). The adjusted cumulative sPTB risks at ≤32 weeks were 0.4% for the LR group, 1.6% for the MR group, and 7.5% for the HR group. Compared to the LR group, the risk ratios for MR and HR groups were 4.25 (95% CI 2.2–7.9) and 19.92 (95% CI 10.4–37.4), respectively.  

Investigators concluded a first-trimester CMP protein biomarker panel effectively stratified risk for sPTB across various gestational ages, enabling early risk assessment and leading to tailored preventative care. 

Source: ajog.org/article/S0002-9378(24)00614-8/fulltext