How Maternal BMI Modifies the Impact of Personalized Asthma Management in Pregnancy

J Allergy Clin Immunol Pract. 2020 Jan;8(1):219-228.e3. doi: 10.1016/j.jaip.2019.06.033. Epub 2019 Jul 10.


Background: Maternal asthma is associated with perinatal complications and respiratory illness in offspring. Obesity increases asthma exacerbation risk in pregnancy and risk of wheeze in offspring.

Objectives: In this secondary analysis of a randomized controlled trial, we investigated the influence of maternal body mass index, gestational weight gain (GWG), and fractional exhaled nitric oxide (FENO)-based management on asthma exacerbations in pregnancy and offspring wheeze.

Methods: A total of 220 women were randomized to asthma treatment adjustment according to symptoms (control group), or FENO and symptoms (FENO group). Exacerbations were recorded prospectively. Height and weight were measured at baseline, and in late pregnancy. GWG was categorized according to Institute of Medicine guidelines. A validated parent-completed questionnaire assessed infant wheeze-related outcomes.

Results: FENO-based management was associated with a significantly lower incidence rate ratio for maternal exacerbations in nonobese mothers (0.52, 95% confidence interval [CI], 0.31-0.88, P = .015, n = 129), and women with GWG within recommendations (0.35, 95% CI, 0.12-0.96, P = .042, n = 43), but not for obese mothers (0.59, 95% CI, 0.32-1.08, P = .089, n = 88), or women with excess GWG (0.58, 95% CI, 0.32-1.04, P = .07, n = 104). Recurrent bronchiolitis occurred in 5.3% (n = 1) of infants born to non-overweight mothers, 16.7% (n = 3) of infants of overweight mothers, and 21.7% (n = 5) of infants of obese mothers in the control group. In the FENO group, 2 infants of obese mothers had recurrent bronchiolitis (7.1%, P = .031).

Conclusions: The benefits of FENO-based management are attenuated among obese mothers and those with excess GWG, indicating the importance of weight management in contributing to improved asthma management in pregnancy.

Keywords: Asthma; Bronchiolitis; Exhaled nitric oxide; F(E)NO; Fractional exhaled nitric oxide; Maternal BMI; Obesity; Pregnancy; Wheeze.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma* / epidemiology
  • Body Mass Index
  • Exhalation
  • Female
  • Humans
  • Infant
  • Obesity / epidemiology
  • Overweight
  • Pregnancy
  • Pregnancy Complications* / epidemiology