Is Twin Pregnancy being a Medical Boon? – Comparative Evaluation on Oxidative Stress in Multiple Pregnancy

Pregnancy, a state of metabolic challenge to be met both by the mother and the developing fetus with a high demand of oxygen. An overproduction of reactive oxygen species (ROS) with greater susceptibility to oxidative stress condition causes impaired blood flow and restricted growth of the fetus. The umbilical cord vessels lack innervations, and therefore the endothelial cells play a determinative role in the control of the blood flow by endothelial nitric oxide (NO) production which gets regulated by the endothelial nitric oxide synthase (NOSIII). In contrast to the beneficial aspect of NO, it also acts as a pro-oxidant molecule, reacts with superoxide anion forming the potent peroxynitrite (ONOO - ) that enhances oxidative macromolecular damages. We aimed to evaluate the redox status of neonatal human red blood cells (RBCs) and endothelial cells derived from umbilical cord vessels, in cases of multiple versus single pregnancy to follow a correlation between the NOSIII activity with maturation of the neonates. In twins, we detected endothelial dysfunction and altered NO production in the cord vessels. As a compensatory mechanism, an increased RBC NOSIII-dependent NO production in the circulating RBCs might improve the blood flow to the fetus. However, the increased NOSIII expression is not necessarily beneficial in the highly oxidative background as a consequence of twin pregnancy.