Do improvements in clinical practice guidelines alter pregnancy outcomes in asthmatic women? A single-center retrospective cohort study

Abstract

Objective

Asthma occurs in ∼17% of Australian pregnancies and is associated with adverse perinatal outcomes, which worsen with poor asthma control. Consequently, the South Australian ‘Asthma in Pregnancy’ perinatal guidelines were revised in 2012 to address management according to severity. This study investigated if these revised guidelines reduced the impact of maternal asthma on risks of adverse perinatal outcomes before (Epoch 1, 2006–2011) and after the revision (Epoch 2, 2013–2018).

Methods

Routinely collected perinatal and neonatal datasets from the Women’s and Children’s Hospital (Adelaide, Australia) were linked. Maternal asthma (prevalence:7.5%) was defined as asthma medication use or symptoms described to midwives. In imputation (n = 59131) and complete case datasets (n = 49594), analyses were conducted by inverse proportional weighting and multivariate logistic regression, accounting for confounders.

Results

Overall, maternal asthma was associated with increased risks of any antenatal corticosteroid treatment for threatened preterm birth (aOR 1.319, 95% CI 1.078–1.614), any Cesarean section (aOR 1.196, 95% CI 1.059–1.351), Cesarean section without labor (aOR 1.241, 95% CI 1.067–1.444), intrauterine growth restriction (IUGR, aOR 1.285, 95% CI 1.026–1.61), and small for gestational age (aOR 1.324, 95% CI 1.136–1.542). After guideline revision, asthma-associated risks of any Cesarean section (p < 0.001), any antenatal corticosteroids (p = 0.041), and small for gestational age (p = 0.050), but not IUGR and Cesarean section without labor, were reduced.

Conclusions

Clinical practice guidelines based on the latest evidence do not guarantee clinical efficacy. Since adverse perinatal outcomes did not all improve, this work highlights the need to evaluate the ongoing impact of guidelines on clinical outcomes.

Keywords:

• Maternal asthma
• pregnancy
• clinical guidelines
• perinatal medicine
• obstetrics

Disclosure statement

The authors report there are no competing interests to declare.

This work was supported by Australian Government; Australian Research Council; Channel 7 Children’s Research Foundation; National Health and Medical Research Council; Healthy Development Adelaide.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.