Asthma in Pregnancy

 Asthma is a heterogeneous disease, usually
characterized by airflow inflammation.
 It is defined by the presence of respiratory
symptoms such as :
• Wheezes.
• Shortness of breath.
• Cough .
• That vary overtime and in intensity, together with variable
airflow limitation.
Definition ( GINA 2014 )
Global strategy for Asthma management and prevention guidelines 2014.

Airway inflammation in Asthma
 The airway inflammation in asthma is persistent even
though symptoms are episodic “intermittent”
 The inflammation affects all airways including in most
patients the upper respiratory tract and nose but its
physiological effects are most pronounced in medium-
sized bronchi.
 The pattern of inflammation in the airways appears to be
similar in all clinical forms of asthma, whether allergic,
non-allergic, or aspirin-induced, and at all ages.
Global strategy for Asthma management and prevention guidelines 2014.

 Airway narrowing “Bronchoconstriction”
Is the final common pathway leading to symptoms and
physiological changes in asthma.
Several factors contribute to the development of airway
narrowing in asthma:
Airway smooth muscle contraction
Airway edema
Airway thickening
Mucus hypersecretion
Asthma Pathophysiology
Global strategy for Asthmamanagement and prevention guidelines 2014.

Asthma Inflammatory Responses
 Asthma has two responses:
Immediate inflammatory responses
Delayed inflammatory responses
Global strategy for Asthmamanagement and prevention guidelines 2014.

Source: Peter J. Barnes, MD
Asthma Inflammation: Cells and Mediators

Risks and Prevalence
Outcomes and complications of asthma in
pregnancy
Pathophysiologic Mechanisms
Asthma Differentials
Examination Findings
Etiologic Factors in Asthma
Blood Work
Chest Radiography
Pulmonary Function Testing
Antiasthma Drugs
Hospital Care
Admission and Discharge
Asthma in pregnancy

Asthma in pregnancy
Asthma is a chronic inflammatory
disease of the airways that is
characterized by increased
responsiveness of the tracheobronchial
tree to multiple stimuli. It is the most
common chronic condition in pregnancy.

Asthma in pregnancy
The disease is episodic, being
characterized by acute exacerbations
intermingled with symptom-free periods.
Most asthma attacks prove to be short-
lived, lasting minutes to hours. Although
patients appear to recover completely
clinically, evidence suggests that
patients with asthma develop chronic
airflow limitations.

Asthma in pregnancy
The prevalence of asthma in the general
population is 4-5%. In pregnancy, the
prevalence ranges from 1-4%.
Asthma-related morbidity and mortality
rates in pregnant women are comparable
to those in the general population. The
mortality rate from asthma in the United
States is 2.1 persons per 100,000.

Asthma in pregnancy
pregnancy
Although women with mild asthma are unlikely to have
problems, patients with severe asthma are at greater risk of
deterioration. The deterioration risk is highest in the last
portion of a pregnancy.
In fact, severe and/or poorly controlled asthma has been
associated with numerous adverse perinatal outcomes,
including the following:
Preeclampsia
Pregnancy related hypertension
Uterine hemorrhage
Preterm Labor

Asthma in pregnancy
pregnancy
Premature birth
Congenital anomalies
Fetal growth restriction
Low birth weight
Neonatal hypoglycemia, seizures, tachypnea, and neonatal
intensive care unit (ICU) admission
This risk of giving birth to a small or preterm infant appears
to be small and may be minimized by good control of asthma.
Studies have indicated that low-birth-weight infants are more
common in women with daily symptoms or low expiratory
flow than in women without asthma.

Asthma in pregnancy
pregnancy
Asthma can also lead to the following
morbidities in pregnant women:
Respiratory failure and the need for mechanical
ventilation
Barotrauma
Complications of (parenteral) steroid use
Death can also occur.

Asthma in pregnancy
Pregnancy has a significant effect on the
respiratory physiology of a woman. While the
respiratory rate and vital capacity does not change
in pregnancy, tidal volume, minute ventilation
(40%), and minute oxygen uptake (20%) increase,
with a resultant decrease in functional residual
capacity and residual volume of air as a
consequence of the elevated diaphragm. In
addition, airway conductance is increased and
total pulmonary resistance is reduced, possibly as
a result of the influence of progesterone.

Asthma in pregnancy
The consequence of these physiologic
changes is a hyperventilatory picture as a
normal state of affairs in the later half of
pregnancy. This results in the picture of a
chronic respiratory alkalosis during
pregnancy, with a decreased partial
pressure of carbon dioxide (pCO2),
decreased bicarbonate, and increased pH.

Asthma in pregnancy
A normal pCO2 in a pregnant patient may
signal impending respiratory failure. The
increased minute ventilation and improved
pulmonary function in pregnancy promote
more efficient gas exchange from the
maternal lungs to the blood. Therefore,
changes in respiratory status occur more
rapidly in pregnant patients than in
nonpregnant patients.

Asthma in pregnancy
Asthma is characterized by inflammation
of the airways, with an abnormal
accumulation of eosinophils,
lymphocytes, mast cells, macrophages,
dendritic cells, and myofibroblasts. This
leads to a reduction in airway diameter
caused by smooth muscle contraction,
vascular congestion, bronchial wall
edema, and thick secretions.

Asthma in pregnancy
Problems to consider that can mimic
asthma in pregnant patients include the
following:
Airway obstruction
Amniotic fluid embolism
Acute congestive heart failure (CHF),
secondary to peripartum
cardiomyopathy
Physiologic dyspnea of pregnancy

Asthma in pregnancy
Cough
Shortness of breath
Chest tightness
Noisy breathing
Nocturnal awakenings
Recurrent episodes of symptom complex
Exacerbations possibly provoked by
nonspecific stimuli
Personal or family history of other atopic
disease (eg, hay fever, eczema)
and infections

Asthma in pregnancy
General physical examination findings may
include the following:
Tachypnea
Retraction (sternomastoid, abdominal,
pectoralis muscles)
Agitation, usually a sign of hypoxia or
respiratory distress
Pulsus paradoxicus (>20 mm Hg)

Asthma in pregnancy
Pulmonary findings are as follows:
Diffuse wheezes - Long, high-pitched
sounds on expiration and, occasionally,
on inspiration)
Diffuse rhonchi
Expiratory phase of respiration equal to
or more prominent than inspiratory phase

Asthma in pregnancy
Signs of fatigue and near-respiratory arrest
are as follows:
Alteration in the level of consciousness,
such as lethargy, which is a sign of
respiratory acidosis and fatigue
Abdominal breathing
Inability to speak in complete sentences

Asthma in pregnancy
Signs of complicated asthma are as
follows:
Equality of breath sounds: Check for equality of breath
sounds (pneumonia, mucous plugs, barotrauma). The
amount of wheezing does not always correlate with the
severity of the attack. A silent chest in someone in
distress is more worrisome.
Jugular venous distension from increased intrathoracic
pressure (from a coexistent pneumothorax)
Hypotension and tachycardia (think tension pneumothorax)
Fever, a sign of upper or lower respiratory infections

pregnancy
Etiologic Factors for Asthma
Blood Work
Chest Radiography
Antiasthma Drugs
Hospital Care
Asthma in pregnancy

Asthma in pregnancy
Etiologic factors for asthma
Implicated stimuli include the following:
Allergens, including pollens, house-dust mites, cockroach antigen,
animal dander, molds, and Hymenoptera stings
Irritants, including cigarette smoke, wood smoke, air pollution,
strong odors, occupational dust, and chemicals
Medical conditions, including viral upper respiratory tract infections,
sinusitis, esophageal reflux, and Ascaris infestations
Drugs and chemicals, including aspirin, nonsteroidal anti-
inflammatory drugs, beta blockers, radiocontrast media, and sulfites
Exercise
Cold air
Menses
Emotional stress

Asthma in pregnancy
Blood Work
Complete blood count with differential
A complete blood count (CBC) is performed to assess the
degree of nonspecific inflammation and the possibility of a
comorbid anemia or thrombocytopenia. Leukocytosis may be
the result of a physiologic response to pregnancy, steroid
therapy, upper respiratory tract infections, or the stress of an
asthma attack.

Asthma in pregnancy
Blood Work
Arterial blood gas level
Arterial blood gas (ABG) analysis indicates the level of
oxygenation and respiratory compensation. Partial pressure of
carbon dioxide in the arterial blood (PaCO2) is generally low in
the early stages of an exacerbation as a result of
hyperventilation. An increase in PaCO2 can be a sign of
impending respiratory failure. ABG results often show a
decrease in PaO2. Physiologic changes that accompany
pregnancy in the pulmonary system slightly alter normal ABG
values: pH = 7.4-7.45, pO2 = 95-105 mm Hg, pCO2 = 28-32
mm Hg, and bicarbonate = 18-31 mEq/L.
.

Asthma in pregnancy
Blood Work
Blood cultures
These must be obtained in patients in whom pneumonia is
found or reasonably suggested.

pregnancy
Blood Work
Chest Radiology
Antiasthma Drugs
Hospital Care
Asthma in pregnancy

Asthma in pregnancy
Chest Radiology
A normal chest radiograph in late pregnancy
typically reveals an enlarged heart and some
prominent lung markings from elevation of the
diaphragm. Chest radiography is indicated when
the other coexistent conditions, such as
pneumonia, barotrauma, CHF, or chronic
obstructive pulmonary disease, are likely. Chest
radiographs (2 views) with a shielded maternal
abdomen expose the fetus to approximately
0.00005 rad.
.

Radiographic Signs of Pneumomediastinum
Subcutaneous emphysema
Thymic sail sign
Pneumoprecardium
Ring around the artery sign
Tubular artery sign
Double bronchial wall sign
Continuous diaphragm sign
Extrapleural sign
Air in the pulmonary ligament

Ginkgo leaf sign
• The ginkgo leaf sign is a chest plain radiography
appearance which is seen at extensive subcutaneous
emphysema of the chest wall. Air outlines the fibers of
the pectoralis major muscle and creates a branching
pattern that resembles the branching pattern in the
veins of a ginkgo leaf.

pregnancy
Blood Work
Chest Radiology
Pulmonary Function Tests
Antiasthma Drugs
Hospital Care
Asthma in pregnancy

Asthma in pregnancy
Pulmonary Function Tests
Hand-held peak flow meters are available in most emergency
departments (EDs). If the patient’s baseline is known, clinicians can
use measurement to assess the severity of an attack and the patient’s
response to medications.
Reversible airflow obstruction is central to the diagnosis and
assessment of asthma.
Changes in pulmonary function during acute asthma include the
following:
Decreased peak expiratory flow rate (PEFR) and forced expiratory
volume in 1 second (FEV 1)
Mild reduction in the forced vital capacity (FVC)
An increased residual volume (RV), functional residual capacity(FRC),
and total lung capacity (TLC)
Normal diffusing capacity
Patients with asthma usuallydemonstrate a greater than 12% increase
in FEV1, FVC, and PEFR when treated with bronchodilators.

Asthma in pregnancy
Antiasthma Drugs
Almost all antiasthma drugs are safe to use in pregnancy
and during breastfeeding. In fact, undertreatment of the
pregnant patient is a frequent occurrence, because such
patients are worried about medication effects on the fetus.

Asthma in pregnancy
Antiasthma Drugs
Outpatient management of asthma is similar for the
pregnant patient as it is for the nonpregnant patient. Beta-
adrenergic agonists remain the mainstay of treating
exacerbations and handling mild forms of asthma. Early
research suggests a management algorithm for asthma in
pregnancy based on fraction of exhaled nitric oxide
(FE NO) and symptoms significantly reduces asthma
exacerbations.

Asthma in pregnancy
Antiasthma Drugs
For moderate-persistent asthma, a beta-adrenergic
agonist combined with an inhaled anti-inflammatory agent
or inhaled corticosteroid is recommended for treatment. In
severe asthma, oral corticosteroids and beta agonists are
recommended.

Asthma in pregnancy
Antiasthma Drugs
Corticosteroids can be used in the acute and outpatient
setting and have been shown to be relatively safe in
pregnancy. The intravenous, intramuscular, and oral
preparations can be used for acute exacerbations,
whereas the inhaled preparations are reserved for
outpatient maintenance therapy. Recent data on inhaled
glucocorticoids support its relative safety although there
is the potential risk for offspring endocrine and metabolic
disturbances.

Asthma in pregnancy
Antiasthma Drugs
A longer-acting beta2-adrenoreceptor agonist
(eg, salmeterol), the bronchodilator effects of which last at
least 12 hours, is an effective treatment for nocturnal
asthma.
Historically, methylxanthines and oral beta agonists have
been used to treat asthma. Both have been shown to be
safe in pregnancy but have fallen out of favor for newer
medicines and the inhaled forms, respectively.
Magnesium sulfate is another medication that is safe to
use in pregnancy. It works as a smooth-muscle relaxant of
the airway.

Asthma in pregnancy
Antiasthma Drugs
Epinephrine use should be avoided in the
pregnant patient. In general, epinephrine is
used only in the most severe asthma
exacerbations. In pregnancy, employment
of the drug can lead to possible congenital
malformations, fetal tachycardia, and
vasoconstriction of the uteroplacental
circulation.

Asthma in pregnancy
Hospital Care
Prehospital asthma treatment
Prior to arriving at the ED, address the
patient’s airway status as needed. Provide
early institution of beta-agonist inhalational
therapy. Provide supplemental oxygen.

Asthma in pregnancy
Hospital Care
Treatment in the emergency department
Pregnant patients who present with typical mild exacerbations
of asthma may be treated in the same way that a regular
asthmatic patient with similar symptoms would be, with
bronchodilator therapy and steroids.
Special attention must be given to pregnant patients who
present with severe asthma exacerbations, because the
resulting maternal hypoxia can have devastating
consequences on the fetus.
The American College of Obstetricians and Gynecologists has
issued practice guidelines for the management of asthma
during pregnancy, Asthma in Pregnancy.[8]
As always in the ED, address the ABCs. The patient should be

Asthma in pregnancy
Hospital Care
Pregnant patients who present with typical mild exacerbations
of asthma may be treated in the same way that a regular
asthmatic patient with similar symptoms would be, with
bronchodilator therapy and steroids.
Special attention must be given to pregnant patients who
present with severe asthma exacerbations, because the
resulting maternal hypoxia can have devastating consequences
on the fetus.
The American College of Obstetricians and Gynecologists has
issued practice guidelines for the management of asthma
during pregnancy, Asthma in Pregnancy.

Asthma in pregnancy
Hospital Care
As always in the ED, address the ABCs. The patient
should be placed on a cardiac monitor and pulse oximetry.
The threshold of intubation should be low to prevent/limit
hypoxic episodes to the fetus. Intubate and mechanically
ventilate patients who are in or near respiratory arrest and
patients who do not respond to treatment as evidenced by
the following:
Hypoxemia despite supplemental oxygen
Increasing carbon dioxide retention
Persistent/worsening level of consciousness
Hemodynamic instability
The key to treating asthma in the pregnant patient is to

Asthma in pregnancy
Hospital Care
frequently assess the patient, the severity of the attack, and
the response to treatment.
Hypoxia, acidosis, unequal breath sounds, pneumothorax, and
atypical features serve as warning signs of severe
exacerbations.
Inhaled beta2-agonists are the mainstay of treatment. The
beta2-agonist, inhaled and/or subcutaneous, is typically given
in 3 doses over 60-90 minutes. Beta-adrenergic blocking
agents should be avoided owing to bronchospastic effect.
The early use of systemic steroids has been shown to reduce
the length of stay in the ED and the admission rate; the effect
of steroids is seen within 4-6 hours of the institution of therapy.
Supply supplemental oxygen to maintain oxygen saturation

Asthma in pregnancy
Hospital Care
frequently assess the patient, the severity of the attack,
and the response to treatment.
Hypoxia, acidosis, unequal breath sounds, pneumothorax,
and atypical features serve as warning signs of severe
exacerbations.
Inhaled beta2-agonists are the mainstay of treatment. The
beta2-agonist, inhaled and/or subcutaneous, is typically
given in 3 doses over 60-90 minutes. Beta-adrenergic
blocking agents should be avoided owing to
bronchospastic effect.

Asthma in pregnancy
Hospital Care
The early use of systemic steroids has been shown to
reduce the length of stay in the ED and the admission rate;
the effect of steroids is seen within 4-6 hours of the
institution of therapy.
Supply supplemental oxygen to maintain oxygen
saturation higher than 95%. Intravenous fluids can help to
loosen and clear secretions.
Fetal monitoring becomes important after 20 weeks of
gestation in severe cases.

Asthma in pregnancy
Hospital Care
Tranquilizers and sedatives should be avoided because of
their respiratory depressant effect. Antihistamines are not
useful in the treatment of asthma. Mucolytic agents
increase bronchospasm.
Less than 1% of all asthmatic patients require mechanical
ventilation. Asthmatic patients have higher complication
rates from mechanical ventilation. Increased airway
resistance may result in extremely high peak airway
pressures, barotraumas, and hemodynamic impairment.
Mucous plugging is common, increasing airway
resistance, atelectasis, and the incidence of secondary
pneumonia. Paradoxical increases in bronchospasm may
occur from aggravation by the endotracheal tube.

Asthma in pregnancy
Hospital Care
Typical ventilator settings may lead to stacked breaths and
increased airway pressures. Decrease the ratio of the
duration of inspiration to the duration of expiration (I:E
ratio), and set a low respiratory rate to allow for adequate
expiration.

Asthma in pregnancy
Criteria for hospital admission are as
follows:
Inadequate response to ED therapy
pO 2 less than 70 mm Hg
Signs of fetal distress (eg, decreased movement,
abnormal cardio tocodynamometry, uterine contractions)
Multiple medication use (ie, requiring 3 or more
medications simultaneously)
A protracted course with poor response to outpatient
therapy thus far instituted or a history of severe asthma
requiring intubation or ICU admission
Inadequate home conditions and transport/access to ED
care

Asthma in pregnancy
Criteria for ICU admission are as follows:
:
Altered level of consciousness
Poor air flow
Signs of fatigue, a downhill course, or a need
for mechanical ventilation
PEFR/FEV 1 less than 25% of predicted or
pCO 2 greater than 35 mm Hg

Asthma in pregnancy
Criteria for home discharge include the
following:
Greatly improved symptoms and physical
examination findings
Ability of the patient to walk out of the ED
without obvious distress
PEFR/FEV 1 greater than 70% baseline
No fetal distress
Good follow-up and access to ED in case of
relapse

Asthma in pregnancy
A follow-up appointment 2-4 days following the
ED visit is recommended. Consider referral to an
asthma specialist; in addition, involvement of a
multidisciplinary team that includes a
pulmonologist, neonatologist and obstetrician,
should be considered in the follow-up of a
pregnant asthma woman. Glucocorticoids at the
time of discharge have proven to be useful and to
reduce the incidence of ED visits.

Asthma in Pregnancy

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