Can inflammatory markers predict the risk of preterm and early preterm birth in women with threatened preterm labor?

OBJECTIVE

To evaluate neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), systemic inflammation response index (SIRI), and other related indices measured at the time of admission for threatened preterm labor and their association with the risk of preterm birth.

METHODS

A prospective observational cohort study was conducted between January 2021 and December 2023 at two regional maternity hospitals. Blood samples were collected from all patients upon hospitalization, prior to the administration of any medical treatment. Patients were categorized into two groups based on delivery time: preterm birth and term delivery. The preterm birth group was further subdivided into early preterm birth (<34 weeks) and late preterm birth (34-36.6 weeks). Demographic characteristics, complete blood count parameters, and systemic inflammatory indices were compared across these groups. To identify independent predictors of preterm birth and early preterm birth, multivariate logistic regression analysis was performed.

RESULTS

The final analysis included 311 pregnant women admitted for threatened preterm labor. The preterm birth group had a higher maternal age and a lower gestational age at admission compared to the term delivery group (p = 0.04, p = 0.02, respectively). The preterm group was statistically associated with higher WBC, neutrophil count, monocyte count, and platelet count. Furthermore, the median NLR, SII, and SIRI values were significantly higher in the preterm group. After adjusting for confounders multivariate regression analysis showed that higher levels of NLR and SII were independently associated with an increased risk of preterm birth.

CONCLUSION

We found that NLR and SII are independent prognostic markers for preterm birth in patients with TPTL, and they demonstrate superior prognostic ability compared to single hemogram parameters.