Study of Nitric Oxide and Lipid Peroxidation in Preterm Labour: A Case-control Study

Abstract

Introduction: Preterm Labour (PTL) is a major obstetric health problem. It contributes to 75% of neonatal mortality worldwide. According to a World Health Organisation (WHO) report, 15 million preterm birth occur every year. Nitric Oxide (NO), synthesised by three isoforms of NO Synthase (NOS) play physiological role in uterine muscle relaxation and prevention of preterm labour contractions. NO is also demonstrated to react with Reactive Oxygen Species (ROS). Aim: To assess the level of serum NO, Malondialdehyde (MDA) (end product of lipid peroxidation), total protein, albumin, calcium, and inorganic phosphorus in PTL) and also to compare these parameters with full-term labour. Materials and Methods: A case-control study was conducted in the Department of Biochemistry and Obstetrics and Gynaecology, Government Medical College, Miraj, Maharashtra, India, during the period of November 2014 to May 2015. Study included 60 women with age ranged between 21-31 years and gestational age between 28 to 37 weeks. Out of total 60 women, 30 were full-term labour, served as control and 30 women who had regular uterine contraction before 37 weeks were selected as cases. Estimation of NO (as nitrite) and MDA, Total Protein (TP), Albumin, Calcium and Inorganic Phosphorus was done. Data were analysed by applying a Student’s t-test and Pearson correlation test. Results: The mean maternal age was 26.53±3.42 years for cases and for control 27.63±2.51 years. The mean gestational age in cases was 31.1±2.795 weeks, whereas in controls was 37.26±0.520 weeks. A highly significant decrease in NO (7.1967±1.236 μmol/L and 15.900±3.897 µmol/L in PTL and control group), TP (4.996±0.509 g/dL and 6.906±0.480 g/ dL in PTL and control group), Albumin (3.460±0.440 g/dL and 4.406±0.390 g/dL in PTL and control group), calcium (8.240±0.431 mg/dL and 8.950±0.486 mg/dL in PTL and control group) and inorganic phosphorus (2.006±0.532 mg/dL and 3.786±0.537 mg/dL in PTL and control group) concentration was observed in PTL as compared to the controls. Lipid peroxidation (MDA) (10.590±0.8715 mg/dL and 5.6500±0.4725 mg/dL in PTL and control group) was found to be significantly increased in PTL as compared to controls. Conclusion: There was significant drop in the NO and increase in ROS reflected by increase in serum MDA levels in PTL group as compared to normal full-term labour. These parameters may have role in the diagnosis and prevention of PTL after appropriate larger cohort studies.