Maternal serum cytokine levels in pregnancies complicated with threatened preterm labour.

Objective: To investigate serum inflammatory markers in singleton gestations complicated with threatened preterm labour (TPL).

Methods: Pregnant women complicated with TPL (n = 61) were recruited to measure maternal serum levels of a panel of cytokines and C-reactive protein and then compared to controls without TPL, matched for gestational age (n = 64) and term pregnancies in the prodromal phase of labour (PPL) (n = 31). In addition, baseline cytokine levels were compared among cases and controls according to the outcome.

Results: Women with TPL displayed higher CRP and white blood counts levels together with lower granulocyte macrophage colony-stimulating factor (GMC-SF) compared to both controls without TPL and to term gestations in the PPL. Also, interleukin 10 (IL-10), IL-6, IL-7, IL-8 and tumour necrosis alpha (TNF-α) levels were found significantly higher in TPL cases as compared to controls without TPL and term women in the PLL. Baseline cytokine levels (except IL-10) were higher among TPL cases who later delivered preterm. TPL cases delivering preterm displayed lower GMC-SF levels as compared to those delivering at term. Multivariate analysis found that gestational age at birth positively correlated with cervical length and inversely with CRP, IL-6 and TNF-α levels (p < 0.0001).

Conclusions: TPL and preterm birth were related to inflammatory changes in the maternal side that correlate with cervical shortening and the initiation of uterine contractions.