Correlation of Levels of Serum Nitric Oxide with Dual Markers-a Pilot Study

Nitric oxide (NO) is a free radical. It is a major paracrine mediator and important regulatory agent in various female reproductive processes, such as ovulation, implantation, pregnancy maintenance, labor and delivery. This study was done to assess the correlation of nitric oxide with free [beta]-hCG, PAPP-A and age. The objective of the study was to estimate serum nitric oxide levels in first trimester pregnancy and to correlate these values with serum free [beta]-hCG, PAPP-A and age. After obtaining approval from Institutional Ethical committee, serum samples (n = 92) collected for first trimester screening were used for the study. Serum NO was measured using Griess method. Free [beta]-hCG, PAPP-A were measured by immunoassay method (cobase601analyser). The study subjects were divided into 2 groups based on age:-group 1 age 30 years. The study showed that Median values of NO, free [beta]-hCG, PAPP-A were found to be elevated in group 2 compared to group 1. NO with dual marker showed positive correlation. Free [beta]-hCG plays a role in NO release by inducing phosphorylation of NO synthase, thus elevated serum NO levels. PAPP-A inactivates IGF-1 binding proteins that raise serum IGF-1 levels which leads to elevation of serum NO levels. Further studies are required to correlate the elevated serum NO levels with increasing age.