Exhaled Nitric Oxide in Pregnant Healthy and Asthmatic Women

Abstract

Measurement of fractioned exhaled nitric oxide (FE(NO)) is useful for monitoring airway inflammation in asthma. Asthma is one of the most common diseases complicating pregnancy, and FE(NO) may be helpful for monitoring asthma in pregnancy. However, some physiological alterations of FE(NO) may be expected during healthy pregnancy due to vascular nitric oxide production. Until now no study assessed the level of FE(NO) in asthmatic pregnant patients.We aimed to assess the possible use and reproducibility of FE(NO) measurements in pregnant asthmatic women. We compared FE(NO) concentrations between four groups of subjects: healthy nonpregnant and pregnant females and asthmatic nonpregnant and pregnant patients. We also investigated the relationship between FE(NO) values and the level of asthma control in pregnant asthmatic patients.A total of 102 female subjects (35 healthy nonpregnant and 27 healthy pregnant females; 20 nonpregnant and 20 pregnant asthmatic women) were included in this cross-sectional study. Two FE(NO) measurements were performed in each subject using an electrochemical sensor based device (NIOX MINO, Aerocrine, Solna, Sweden). Data are given as median with range.The repeatability of FE(NO) measurement was similar in pregnant and nonpregnant subjects. FE(NO) levels did not differ significantly between healthy pregnant versus nonpregnant subjects (16.0 [8, 31] vs. 16.0 [9, 35] ppb). FE(NO) levels were significantly increased in asthmatic women compared to healthy females (nonpregnant asthmatics: 38 [9, 54] ppb, p < 0.001 vs. healthy nonpregnant; pregnant asthmatic patients: 28 [10, 56] ppb; p < 0.05 vs. healthy pregnant).FE(NO) level is not influenced by healthy pregnancy. In pregnant asthmatic patients FE(NO) level is elevated compared to healthy pregnant subjects and correlates with the level of asthma control. Further studies are required to assess the use of FE(NO) measurement to monitor asthma in this patient group.