Maternal serum ischemia-modified albumin as an oxidative stress biomarker in preterm pre-labor rupture of membranes.

Objectives: To evaluate the maternal serum ischemia-modified albumin (IMA) concentration as an oxidative stress biomarker in pregnancies complicated by preterm pre-labor rupture of membranes (PPROM) without maternal clinical infection and compare these results with healthy pregnancies.

Material and methods: The present cohort study included 40 pregnancies complicated by PPROM and 49 similar gestational age healthy pregnancies in the third trimester of gestation. Maternal venous blood specimens were obtained at the day of first diagnosis. Maternal serum IMA level was assayed with an Albumin Cobalt Binding test. The subjects were followed up until delivery and perinatal outcomes were recorded.

Results: The maternal serum IMA concentrations were significantly higher in the study group (0.56 ± 0.05 absorbance units) as compared to controls (0.54 ± 0.03 absorbance units) (p = 0.020). The maternal serum IMA concentrations were not significantly correlated with the initial maternal white blood cell count (r: 0.118, p = 0.269) and C-reactive protein levels (r: 0.066, p = 0.541). The maternal serum IMA concentrations were negatively correlated with gestational age at delivery (r: -0.248, p = 0.019), birthweight (r: -0.247, p = 0.020) and Apgar scores (r: -0.200, p = 0.049; r: -0.245, p = 0.020). The threshold value of maternal serum IMA concentration above 0.55 absorbance units indicated the pregnancy complicated by PPROM by 57.5% sensitivity and 57.1% specificity (Area under curve 0.613, confidence interval 0.50-0.73).

Conclusions: The current study supported for the first time that there is an association between increased maternal serum IMA levels and the development of PPROM in the third trimester of gestation without maternal clinical infection. Elevated maternal serum IMA levels may alert the obstetrician about poor ongoing perinatal outcomes in the early phase of PPROM before increased maternal C-reactive protein and white blood cell count.