[Significance of fractional exhaled nitric oxide in the diagnosis of asthma in pregnant women].

OBJECTIVE

To assess the variability of fractional exhaled nitric oxide (FeNO) and to explore the significances of FeNO in the diagnosis and treatment of asthma in pregnant women.

METHODS

In a prospective study, 65 healthy pregnant women, 55 asthmatic non-pregnant women, 40 asthmatic pregnant women and 60 healthy non-pregnant women were enrolled in the study from Oct 2012 to Apr 2014.FeNO levels of the 4 groups were compared, and the variability of FeNO in different pregnancy periods of 15 healthy pregnant women were examined.We also analyzed the correlation between the level of FeNO, FEV1% pred, asthma control test (ACT) scores andblood eosinophils in patients of asthmatic pregnant women.

RESULTS

The difference in the levels of FeNO between healthy pregnant women (12 ± 6) ppb and healthy non-pregnant women (14 ± 5) ppb were no significant (t = 0.508, P > 0.05) . The levels of FeNO in different pregnancy periods of healthy pregnant women were not significantly different (F = 0.656, P > 0.05). Compared with healthy pregnant women (12 ± 6) ppb, the level of FeNO was significantly higher in asthmatic pregnant patients (43 ± 21) ppb (t = 2.981, P < 0.05) , but the difference of the levels of FeNO between asthmatic non-pregnant (51 ± 32) ppb and pregnant patients (43 ± 21) ppb were no significant (t = 0.366, P > 0.05) . There was no significant correlation between FeNO level and FEV1% pred (r = 0.164, P > 0.05), nor between FeNO level and ACT scores (r = 0.272, P > 0.05) , but there was significant correlation between FeNO level and eosinophils (r = 0.723, P < 0.05).

CONCLUSIONS

FeNO level is not influenced by pregnancy and different gestation periods.FeNO level in asthmatic pregnant women is increased, and FeNO is an important examination in the diagnosis of asthma during pregnancy.