DOI: 10.1111/tog.12048 2013;15:241–5
The Obstetrician & Gynaecologist
Review
http://onlinetog.org
Asthma in pregnancy
a,b c,
Michelle H Goldie RM, Chris E Brightling PhD FRCP *
a
Honorary Research Associate, Institute for Lung Health, Department of Infection, Immunity & Inflammation, Clinical Sciences Wing, University
Hospitals of Leicester, Leicester LE3 9QP, UK
b
Former Specialist Midwife, Leicester Royal Infirmary, Leicester LE1 5WW, UK
c
Professor of Respiratory Medicine & Honorary Consultant Physician, Institute for Lung Health, Department of Infection, Immunity &
Inflammation, Clinical Sciences Wing, University Hospitals of Leicester, Leicester LE3 9QP, UK
*Correspondence: Professor Chris E Brightling. Email:
Accepted on 8 September 2012
Key content Learning objectives
Asthma is a common condition that affects ~10% of pregnant Comprehensive overview of asthma in pregnancy.
women. Review asthma management in pregnancy.
Pregnancy worsens asthma control in one-third of women,
Ethical issues
improves it in one-third and has no effect on one-third.
Poor asthma control has adverse effects upon maternal and fetal
Are women appropriately counselled on the pregnancy risks of
asthma?
outcomes. Are doctors aware of the safety of routine asthma treatments in
Good asthma management to maintain control is important in line
pregnancy?
with national guidelines.
Standard therapy with inhaled corticosteroids with or without the Keywords: asthma / b-agonists / corticosteroids / pre-eclampsia /
addition of short and long-acting b-agonists can be used in pregnancy
pregnancy.
Please cite this paper as: Goldie MH, Brightling CE. Asthma in pregnancy. The Obstetrician & Gynaecologist 2013;15:241–5.
conversely asthma can affect pregnancy. Importantly, the
Introduction
British Thoracic Society/Scottish Intercollegiate Guideline
Asthma affects an estimated 235 million people worldwide Network (BTS/SIGN) asthma guideline on the management
and the burden is likely to rise substantially in the of asthma apply in pregnancy and good asthma control
next few decades.1–3 The condition causes about 239 000 during pregnancy is critical.7
deaths per year (0.4% of all deaths due to disease) and
results in a large burden of disability. The total cost of
asthma in Europe is estimated to be €17.7 billion Box 1. Triggers for asthma
per annum.2
Asthma is a chronic inflammatory disease of the airways, Allergens, such as house dust mite, pollen, etc.
which is characterised by intermittent episodes of wheeze, Smoking
Exercise
shortness of breath, chest tightness and cough, which are
Occupational exposure
often worse at night. It is a variable disease where Pollution
inflammation and structural changes can occur in the Drugs, such as aspirin, b-blockers
airway in response to certain stimuli or triggers (Box 1).3,4 Food and drinks such as dairy produce, alcohol, peanuts and orange
juice
This causes airway hyper-responsiveness and variable
Additives such as monosodium glutamate and tartrazine
airflow obstruction leading to the symptoms described. Medical conditions, such as rhinitis and gastric reflux
Patients suffer from flare-ups or exacerbations of their Hormonal, such as premenstrual conditions and pregnancy
disease either in response to an acute infection, which is
usually viral in origin, or due to poor control of their
airway inflammation.
Breathlessness in pregnancy
The prevalence of asthma in pregnant women is 4–12%,
making it the most common chronic condition in Breathlessness is the sensation of feeling out-of-breath or
pregnancy.5,6 Pregnancy can affect asthma control and unable to catch your breath. A healthy respiratory rate is
ª 2013 Royal College of Obstetricians and Gynaecologists 241
, Asthma in pregnancy
12–20 breaths/minute at rest. A persistent respiratory rate
Box 3. Physiological factors affecting asthma in pregnancy
at rest >24 breaths/minute is abnormal. Breathlessness in
pregnancy is extremely common and may reflect either Increase in free cortisol levels may protect against inflammatory
the normal anatomical and physiological changes that triggers.
occur in pregnancy, or anxiety, or may be a consequence Increase in bronchodilating substances (such as progesterone) may
of an underlying pathology. Therefore, in a woman with improve airway responsiveness.
Increase in bronchoconstricting substances (such as prostaglandin
known asthma the cause of increased breathlessness may F2a) may promote airway constriction.
not be due to asthma. Similarly, in a woman not Placental 11b-hydroxysteroid dehydrogenase type 2 decreased
diagnosed as asthmatic new incident asthma can be the activity is associated with an increase in placental cortisol
cause of breathlessness, albeit rarely. The causes of concentration and low birthweight.
Placental gene expression of inflammatory cytokines may promote
breathlessness to be considered in pregnancy are shown low birthweight.
in Box 2. Modification of cell-mediated immunity may influence maternal
response to infection and inflammation.
Box 2. Main differential diagnoses in pregnant women with dyspnoea
The effects of asthma on pregnancy
Anxiety
Hyperventilation Where risks have been reported the data on the effects of
Dysfunctional breathing
asthma on pregnancy outcomes is conflicting.12–14 This is
Respiratory disease:
– asthma probably due to differences in study designs, asthma severity
– chest infection and/or pneumonia and its management in different studies and inadequate
– thromboembolic disease consideration of potential confounders. There are limited
– interstitial lung disease, e.g. sarcoid or secondary to a connective
tissue disorder
data on how asthma control prior to pregnancy influences
– pneumothorax pregnancy outcomes, although in one case–controlled study
– amniotic fluid embolism of two-thousand women, poor asthma control and disease
Cardiac disease: severity prior to pregnancy were associated with an elevated
– arrhythmias
– ischaemic heart disease
risk of hypertension in pregnancy.15 This is consistent with
– cardiomyopathy previous studies that have demonstrated an association
Endocrine disease: between asthma and hypertension during pregnancy,8 and
– diabetes mellitus leading to hyperventilation in the setting of two large, multicentre, prospective studies that found in
acute ketoacidosis
– acute thyrotoxicosis women with daily asthma symptoms16 or impaired lung
Haematological: function17 there was an increase in hypertension. In contrast,
– chronic anaemia a systematic review that included nearly one thousand
– acute haemorrhage
women found that asthma exacerbations were not
Renal disease:
– hyperventilation to compensate for metabolic acidosis secondary associated with an increased risk of pre-eclampsia.8,13
to acute renal failure Recent evidence suggests that airway hyper-responsiveness
– a hallmark of asthma – may be a predictor of pre-eclampsia
and points to a mechanistic common pathway of mast cell–
airway smooth muscle cell interactions.18
The effects of pregnancy on asthma Retrospective and prospective studies have demonstrated
The severity of asthma during pregnancy remains that women with asthma have a higher frequency of caesarean
unchanged, worsens or improves in equal proportions.8 section than women without asthma.8 Intrauterine growth
Box 3 describes physiological factors that affect asthma restriction or low birthweight were observed in retrospective
during pregnancy. In severe disease, asthma control is more studies but this has not been replicated in large prospective
likely to deteriorate (~60%) than in mild disease (~10%).9,10 studies. However, low birthweight is associated with measures
Exacerbations are most common between 24 and 36 weeks of poor asthma control such as persistent daily symptoms or
of pregnancy.9,11 Respiratory viral infections were the most poor lung function.16,17 and in women not using inhaled
frequent triggers of exacerbations (34%), followed by poor corticosteroids.12 Similarly in a systematic review, of nearly
adherence to inhaled corticosteroid therapy (29%).9 one thousand women, asthma exacerbations during
Therefore, during pregnancy women with asthma need to pregnancy increased the risk of low birthweight compared
be closely reviewed throughout pregnancy, irrespective of to women with asthma without exacerbations and women
disease severity. without asthma.13
242 ª 2013 Royal College of Obstetricians and Gynaecologists
The Obstetrician & Gynaecologist
Review
http://onlinetog.org
Asthma in pregnancy
a,b c,
Michelle H Goldie RM, Chris E Brightling PhD FRCP *
a
Honorary Research Associate, Institute for Lung Health, Department of Infection, Immunity & Inflammation, Clinical Sciences Wing, University
Hospitals of Leicester, Leicester LE3 9QP, UK
b
Former Specialist Midwife, Leicester Royal Infirmary, Leicester LE1 5WW, UK
c
Professor of Respiratory Medicine & Honorary Consultant Physician, Institute for Lung Health, Department of Infection, Immunity &
Inflammation, Clinical Sciences Wing, University Hospitals of Leicester, Leicester LE3 9QP, UK
*Correspondence: Professor Chris E Brightling. Email:
Accepted on 8 September 2012
Key content Learning objectives
Asthma is a common condition that affects ~10% of pregnant Comprehensive overview of asthma in pregnancy.
women. Review asthma management in pregnancy.
Pregnancy worsens asthma control in one-third of women,
Ethical issues
improves it in one-third and has no effect on one-third.
Poor asthma control has adverse effects upon maternal and fetal
Are women appropriately counselled on the pregnancy risks of
asthma?
outcomes. Are doctors aware of the safety of routine asthma treatments in
Good asthma management to maintain control is important in line
pregnancy?
with national guidelines.
Standard therapy with inhaled corticosteroids with or without the Keywords: asthma / b-agonists / corticosteroids / pre-eclampsia /
addition of short and long-acting b-agonists can be used in pregnancy
pregnancy.
Please cite this paper as: Goldie MH, Brightling CE. Asthma in pregnancy. The Obstetrician & Gynaecologist 2013;15:241–5.
conversely asthma can affect pregnancy. Importantly, the
Introduction
British Thoracic Society/Scottish Intercollegiate Guideline
Asthma affects an estimated 235 million people worldwide Network (BTS/SIGN) asthma guideline on the management
and the burden is likely to rise substantially in the of asthma apply in pregnancy and good asthma control
next few decades.1–3 The condition causes about 239 000 during pregnancy is critical.7
deaths per year (0.4% of all deaths due to disease) and
results in a large burden of disability. The total cost of
asthma in Europe is estimated to be €17.7 billion Box 1. Triggers for asthma
per annum.2
Asthma is a chronic inflammatory disease of the airways, Allergens, such as house dust mite, pollen, etc.
which is characterised by intermittent episodes of wheeze, Smoking
Exercise
shortness of breath, chest tightness and cough, which are
Occupational exposure
often worse at night. It is a variable disease where Pollution
inflammation and structural changes can occur in the Drugs, such as aspirin, b-blockers
airway in response to certain stimuli or triggers (Box 1).3,4 Food and drinks such as dairy produce, alcohol, peanuts and orange
juice
This causes airway hyper-responsiveness and variable
Additives such as monosodium glutamate and tartrazine
airflow obstruction leading to the symptoms described. Medical conditions, such as rhinitis and gastric reflux
Patients suffer from flare-ups or exacerbations of their Hormonal, such as premenstrual conditions and pregnancy
disease either in response to an acute infection, which is
usually viral in origin, or due to poor control of their
airway inflammation.
Breathlessness in pregnancy
The prevalence of asthma in pregnant women is 4–12%,
making it the most common chronic condition in Breathlessness is the sensation of feeling out-of-breath or
pregnancy.5,6 Pregnancy can affect asthma control and unable to catch your breath. A healthy respiratory rate is
ª 2013 Royal College of Obstetricians and Gynaecologists 241
, Asthma in pregnancy
12–20 breaths/minute at rest. A persistent respiratory rate
Box 3. Physiological factors affecting asthma in pregnancy
at rest >24 breaths/minute is abnormal. Breathlessness in
pregnancy is extremely common and may reflect either Increase in free cortisol levels may protect against inflammatory
the normal anatomical and physiological changes that triggers.
occur in pregnancy, or anxiety, or may be a consequence Increase in bronchodilating substances (such as progesterone) may
of an underlying pathology. Therefore, in a woman with improve airway responsiveness.
Increase in bronchoconstricting substances (such as prostaglandin
known asthma the cause of increased breathlessness may F2a) may promote airway constriction.
not be due to asthma. Similarly, in a woman not Placental 11b-hydroxysteroid dehydrogenase type 2 decreased
diagnosed as asthmatic new incident asthma can be the activity is associated with an increase in placental cortisol
cause of breathlessness, albeit rarely. The causes of concentration and low birthweight.
Placental gene expression of inflammatory cytokines may promote
breathlessness to be considered in pregnancy are shown low birthweight.
in Box 2. Modification of cell-mediated immunity may influence maternal
response to infection and inflammation.
Box 2. Main differential diagnoses in pregnant women with dyspnoea
The effects of asthma on pregnancy
Anxiety
Hyperventilation Where risks have been reported the data on the effects of
Dysfunctional breathing
asthma on pregnancy outcomes is conflicting.12–14 This is
Respiratory disease:
– asthma probably due to differences in study designs, asthma severity
– chest infection and/or pneumonia and its management in different studies and inadequate
– thromboembolic disease consideration of potential confounders. There are limited
– interstitial lung disease, e.g. sarcoid or secondary to a connective
tissue disorder
data on how asthma control prior to pregnancy influences
– pneumothorax pregnancy outcomes, although in one case–controlled study
– amniotic fluid embolism of two-thousand women, poor asthma control and disease
Cardiac disease: severity prior to pregnancy were associated with an elevated
– arrhythmias
– ischaemic heart disease
risk of hypertension in pregnancy.15 This is consistent with
– cardiomyopathy previous studies that have demonstrated an association
Endocrine disease: between asthma and hypertension during pregnancy,8 and
– diabetes mellitus leading to hyperventilation in the setting of two large, multicentre, prospective studies that found in
acute ketoacidosis
– acute thyrotoxicosis women with daily asthma symptoms16 or impaired lung
Haematological: function17 there was an increase in hypertension. In contrast,
– chronic anaemia a systematic review that included nearly one thousand
– acute haemorrhage
women found that asthma exacerbations were not
Renal disease:
– hyperventilation to compensate for metabolic acidosis secondary associated with an increased risk of pre-eclampsia.8,13
to acute renal failure Recent evidence suggests that airway hyper-responsiveness
– a hallmark of asthma – may be a predictor of pre-eclampsia
and points to a mechanistic common pathway of mast cell–
airway smooth muscle cell interactions.18
The effects of pregnancy on asthma Retrospective and prospective studies have demonstrated
The severity of asthma during pregnancy remains that women with asthma have a higher frequency of caesarean
unchanged, worsens or improves in equal proportions.8 section than women without asthma.8 Intrauterine growth
Box 3 describes physiological factors that affect asthma restriction or low birthweight were observed in retrospective
during pregnancy. In severe disease, asthma control is more studies but this has not been replicated in large prospective
likely to deteriorate (~60%) than in mild disease (~10%).9,10 studies. However, low birthweight is associated with measures
Exacerbations are most common between 24 and 36 weeks of poor asthma control such as persistent daily symptoms or
of pregnancy.9,11 Respiratory viral infections were the most poor lung function.16,17 and in women not using inhaled
frequent triggers of exacerbations (34%), followed by poor corticosteroids.12 Similarly in a systematic review, of nearly
adherence to inhaled corticosteroid therapy (29%).9 one thousand women, asthma exacerbations during
Therefore, during pregnancy women with asthma need to pregnancy increased the risk of low birthweight compared
be closely reviewed throughout pregnancy, irrespective of to women with asthma without exacerbations and women
disease severity. without asthma.13
242 ª 2013 Royal College of Obstetricians and Gynaecologists
