To help reduce asthma exacerbations during pregnancy, a new treatment algorithm has been designed by investigators in Australia. The article is written by Professor Peter Gibson and Heather Powell, Centre for Asthma and Respiratory Diseases, University of Newcastle and Hunter Medical Research Institute, Newcastle, NSW, Australia, and colleagues, and appears in a report in this week’s European Respiratory issue of The Lancet.

The most common medical disorder to complicate pregnancy is asthma, and both mothers and health professionals expect it to be managed with as little drug exposure as possible to the developing fetus. Earlier investigations have revealed that corticosteroid treatment for asthma might be more successful when based on actual measures of airway inflammation, and one potential measure is the fraction of exhaled nitric oxide (FENO- a direct marker of inflammation). In this new research, the Managing Asthma in Pregnancy (MAP) investigation, the scientists developed an enhanced FENO-based treatment algorithm and tested its applicability for the adjustment of therapy for asthma during pregnancy.

The study evaluated 220 pregnant women who were non-smokers with asthma, and before 22 weeks gestation they were randomly assigned to treatment adjustment at monthly visits either by an algorithm using clinical symptoms (control group) or FENO concentrations (active intervention group). The FENO group started off with 111 women, of whom 100 completed the trial, and the control group began with 109 women (103 completed). The exacerbation rate was found to be half lower in the active intervention group compared to the control group (0-29 vs 0-62 exacerbations per pregnancy).

Reduction in the frequency of exacerbations was accompanied by significant changes in maintenance asthma pharmacotherapy, which included at a reduced daily dose, more frequent use of inhaled corticosteroid as well as earlier introduction of second line medications, such as long-acting β2 agonists. Maintenance asthma pharmacotherapy based only on symptoms can lead to overtreatment (too high a dose of inhaled corticosteroids) for some individuals, while others may receive under-treatment (not enough individuals using inhaled corticosteroids). The use of FENO detects women with asymptomatic airway inflammation at risk of asthma exacerbation and allows for improved tailoring of asthma therapy. The researchers conclude:

“Asthma management during pregnancy can be improved by the use of measuring FENO concentration, and symptoms to adjust treatment. This algorithmic approach might also be beneficial for non-pregnant women with asthma.”

In a related comment, Dr Stanley J Szefler, Department of Pediatrics, National Jewish Health, Denver, CO, and University of Colorado School of Medicine, Denver, CO, USA, concludes:

“These results lend support to the hypothesis that FENO-guided therapy for asthma in pregnancy could lead to beneficial fetal outcomes; however, this notion needs to be confirmed by further study. Future work should investigate the application of this algorithm in routine antenatal care and other settings.”

Written by Grace Rattue