Background: Pregnancy is associated with significant changes in maternal cardiovascular system which regulates oxygen and nutrient supply to the growing foetus. Nitric oxide, a physiologic vascular smooth muscle relaxant regulates blood flow and therefore may play a role in the cardiovascular changes in pregnancy. The study aimed to determine the levels and changes in maternal serum nitric oxide levels during healthy pregnancy.
Methods: A case-control study was conducted among 32 healthy non-pregnant women as controls and 100 healthy pregnant women (consisting of 33 first trimester, 37 s trimester, and 30 third trimester) as cases. Subjects were consecutively recruited into the study after obtaining an informed consent and meeting the inclusion criteria. Griess Reagent method was used to determine serum nitric oxide levels.
Results: There were no statistically significant difference in the ages and parity of recruited cases and controls. Mean arterial blood pressures were significantly lower (p = 0.009) and serum nitric oxide levels were significantly higher (p < 0.001) in healthy pregnant women compared to healthy non-pregnant women. There was a non-significant progressive increase in serum nitric oxide levels during healthy normal pregnancy.
Conclusions: The finding of a significantly reduced blood pressures and a significant increase in serum nitric oxide levels in healthy pregnancy may suggest a role of nitric oxide in vascular adaptation in pregnancy.
Keywords: Blood pressure; Healthy pregnancy; Non-pregnant; Serum nitric oxide.