Pre-delivery hematological inflammatory indices: associations with maternal age and parity in a delivery cohort

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Aytaç H., Soysal C.

BMC PREGNANCY AND CHILDBIRTH, vol.8, no.4, pp.1-12, 2026 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 8 Issue: 4
  • Publication Date: 2026
  • Doi Number: 10.1186/s12884-026-09924-2
  • Journal Name: BMC PREGNANCY AND CHILDBIRTH
  • Journal Indexes: Academic Search Ultimate (EBSCO), Biomedical Reference Collection: Corporate Edition (EBSCO), Health Research Premium Collection (ProQuest), Scopus, Science Citation Index Expanded (SCI-EXPANDED), CINAHL, EMBASE, MEDLINE, Directory of Open Access Journals
  • Page Numbers: pp.1-12
  • Open Archive Collection: AVESIS Open Access Collection
  • Kütahya Health Sciences University Affiliated: Yes

Abstract

Objective To investigate associations of pre-delivery hematological inflammatory indices, including the sys-

temic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio

(MLR), and platelet-to-lymphocyte ratio (PLR), with maternal age and parity in a delivery cohort.

Methods This retrospective, single-center cohort study included 449 women with naturally conceived singleton

pregnancies. NLR, MLR, PLR, and SII were calculated from a single complete blood count obtained within

24 h before delivery. Associations with maternal age and parity were assessed using nonparametric comparisons,

Spearman correlations with Holm adjustment, and multivariable gamma regression adjusted for BMI, gestational

age, and maternal comorbidity. High SII, defined by the 75th percentile, was examined in a secondary exploratory

logistic model.

Results Mean maternal age was 29.6

±

6.6 years. PLR and SII showed weak positive correlations with both

maternal age and parity, NLR correlated with parity only, and MLR showed no significant correlations after Holm

adjustment. In adjusted index-specific models, maternal age ≥ 35 years was associated with higher NLR, MLR,

PLR, and SII; for SII, the adjusted mean ratio was 1.167 (95% CI: 1.007–1.354). Higher parity was associated

with NLR, PLR, and SII, but not MLR; for SII, each one-unit increase in parity corresponded to an adjusted

mean ratio of 1.113 (95% CI: 1.054–1.174). The exploratory high-SII model showed limited discrimination

(AUC

=

0.602).

Conclusion Maternal age and parity were associated with modest, nonuniform variation across pre-delivery

hematological inflammatory indices. These findings are specific to the pre-delivery setting and should not be

interpreted as establishing a diagnostic threshold or clinical decision rule.