Association of systemic chronic inflammation during pregnancy in different periods and its trajectories with preterm birth.

Abstract

Systemic chronic inflammation (SCI) is a prevalent characteristic observed in various diseases originating from different tissues, while the association of SCI with preterm birth (PTB) remains uncertain. This study aimed to analyze the association between a nonspecific biomarker of SCI and PTB, while also exploring the trajectories of SCI in pregnant women at risk of PTB. The study used data from the Electronic Medical Record System (EMRS) of a hospital in Zhejiang, China and 9226 pregnant women were included. The duration of pregnancy was categorized into four distinct periods: the first, early-second, late-second, and third trimester. Latent class trajectory modeling (LCTM) was used to identify the trajectories of SCI during pregnancy. The elevated WBC counts in the late-second (OR=1.14, 95% CI: 1.06-1.23) and third (OR=1.16, 95% CI: 1.09-1.24) trimester were both positively associated with an evaluated risk of PTB. Moreover, significant dose-response relationships were observed. There were three distinct SCI trajectories found: progressing SCI (2.89%), high SCI (7.13%), and low SCI (89.98%). Pregnant women with progressive SCI had the highest risk of PTB (OR=3.03, 95% CI: 1.47-6.25). In conclusion, elevated SCI after 23weeks was a risk factor for PTB in healthy women, even if the SCI indicator was within normal range. Pregnant women with progressive SCI during pregnancy had the highest risk of PTB.