Undiagnosed asthma common among women referred for fertility treatment, Danish study finds

Combining a symptom questionnaire with fractional exhaled nitric oxide (FeNO) testing could offer a simple, non-invasive way to identify women who need further respiratory assessment.

Asthma is common among women of reproductive age and has been linked to infertility and adverse pregnancy outcomes. Well-controlled asthma is thought to improve both fertility and pregnancy outcomes, yet the condition is frequently underdiagnosed. Researchers in Denmark have now assessed whether a short symptom questionnaire, combined with a breath test, could help identify current asthma in women referred for fertility treatment.

How the study worked

The cross-sectional observational study was carried out within the PRO-ART study at four Danish hospitals. Women referred for fertility treatment completed the Life Quality Test (LQT), a symptom questionnaire developed by the American College of Allergy, Asthma and Immunology.

Women who answered yes to questions on the LQT were invited to a screening visit. This included spirometry, bronchial provocation testing and FeNO measurement, with asthma diagnosis based on the bronchial provocation result.

Results

Of the 188 women who were screened, 119 (63.3%) had asthma. Of these, 47 (39.4%) had no previous asthma diagnosis.

FeNO alone was only weakly predictive of asthma (odds ratio [OR] 1.04, p=0.036). LQT scores were stronger predictors (OR 1.40, p<0.001). When the two measures were combined, predictive value was good, with an area under the curve (AUC) of 0.82.

Using a grid-search algorithm, the researchers identified thresholds for a screening tool. Women were classed as having probable asthma if they met any of these criteria:

• an LQT score of 7 or above
• a FeNO level of 25 ppb or above
• an LQT score of at least 5 but below 7, combined with a FeNO level of 12–25 ppb.

This algorithm achieved 87.9% sensitivity and 55.4% specificity.

What this means

The authors conclude that undiagnosed asthma is common among women referred for fertility treatment. They say combining FeNO with LQT scores is a feasible, non-invasive way to screen for probable asthma.

Only women who reported symptoms on the questionnaire were invited for testing, so the 63.3% figure applies to this symptom-positive group rather than to all women referred for fertility treatment. The algorithm also prioritises sensitivity over specificity, which means almost half of women without asthma would still be flagged for further testing. The researchers note that the approach needs to be validated in larger cohorts.

Source: PubMed, PMID 42899102