MANAGEMENT OF ASTHMA DURING
PREGNANCY
Diagnosis and Monitoring
The diagnosis of asthma is usually known before
pregnancy; however, there are a further proportion
of pregnant women who possibly have asthma.
2
In the latter case, reduced forced expiratory
volume in one second (FEV1), or ratio of FEV1 to
forced vital capacity (FVC), and a 12% or greater
improvement in FEV1 after inhalation of rapid acting
beta-agonist confirm the diagnosis. Lacking safety
data, the bronchial hyperresponiveness test is
contraindicated during pregnancy, thus women
with a clinical picture of new-onset asthma
without spirometric confirmation of the diagnosis
should be treated for asthma during pregnancy.
Skin prick tests are not recommended due to
risk of systemic reactions, but blood tests for
specific IgE antibodies to suspected allergens may
be evaluated.
52
Monthly assessments are required in all asthmatic
pregnant women. Beyond asthma control evaluation,
physical examination and spirometry, evaluation
of arterial oxygen saturation is important: at least
95% measured by pulse oximetry is recommended
52
because, due to pregnancy, induced physiological
hyperpnoea
53,54
and even mild maternal hypoxaemia
may represent respiratory compromise during
pregnancy. Fractioned concentration of nitric
oxide present in exhaled breath (FENO) reflects
airway inflammation in asthma.
55
This method has
been shown to be applicable also in asthmatic
pregnant patients;
60
contrarily, a recent longitudinal
study found large intrasubject variability in
pregnant asthmatics, regardless of the degree of
asthma control.
57
However, asthma exacerbation
rate, such as neonatal hospitalisations, could be
reduced by treating pregnant patients according to
a FENO-based treatment algorithm.
58
Regarding obstetrical care, ultrasonographic
examinations are recommended in the first trimester
to confirm the accuracy of the estimated due date,
anytime after recovery from a severe exacerbation
and serially from the 32
nd
gestational week (together
with nonstress testing), in case of suboptimally
controlled or moderate to severe asthma, to
monitor foetal growth and wellbeing.5