asthma in pregnancy

1. Faculty of medicine
Ain shams university
Pr.Fawzia Abo Ali

2. “The care of the woman with asthma
when she is pregnant differs from
that when she is not.”
Greenburger & Patterson, NEJM 312:897, 1985
Titles:
 Immunological ,resp. &hormonal changes
 impact on mother &fetus
 Exacerbation
 Diagnosis
 Treatment: drug safety

3. Asthma During Pregnancy
Prevalence: %4,7-8,4
Ann Epidemiol 2003;13:317
“Rule of Thirds”
•1/3 better %36
•1/3 same %23
•1/3 worse %41

4. Factors affecting asthma in pregnancy

5. Immunological changes
Cellular immunity
Anti-viral immunity
allograft rejection
autoimmunity
Humoral immunity
Parasitic immunity
allergic responses
T reg
Asthma is as allergic T helper
cell 2 (Th2) type inflammation
that leads to bronchial
hyperresponsiveness, airway
obstruction and

6. Immune tolerance in pregnancy
Pregnancy is characterized by a physiological immunosuppression,
tolerance that protects the fetus from maternal immune response
against paternal antigens expressed by the fetus.

7. immune tolerance during pregnancy
 Tregs exert inhibitory effects on natural killer
lymphocytes responsible for protection against viruses
 that may contribute to increased susceptibility to viral
infections (e.g. influenza) during pregnancy, as observed
by H1N1 influenza in 2009.
 Upregulation of TH2 increases allergic response
Su, L.L., etal . Lancet. 2009; 374: 1417
Viral
infection
allergy

8. Respiratory changes in pregnancy
1. Airway resistance is reduced due to the progesterone-mediated
bronchial and tracheal smooth muscle relaxation.
2. hypersensitivity to CO2 increases the respiratory rate by 15%
3. alveolar ventilation is about 70% higher at the end of gestation.
4. fall in arterial and alveolar carbon dioxide tensions .
5. The development of alkalosis is forestalled by compensatory
decreases in serum bicarbonate.
Oxygen consumption and carbon dioxide production are
increased by 60 %.

9. pulmonary function:
Unchanged: respiratory rate, vital capacity, inspiratory reserve volume
Decreased: functional residual capacity by 20, % expiratory reserve volume
(by 20, % residual volume (by 20, % total lung capacity (by 5%
Increased: inspiratory capacity (by 5 , % tidal volume (by 30-40%
FEV1 & PEFR remain unchanged.
.

10. Pregnancy hormones &asthma
 progesterone is a smooth muscle relaxant, which may
explain improved asthma in some patients.
 both progesterone and estrogen potentiate b-
adrenergic bronchodilation.
 Increased relaxin levels promote relaxation of bronchial
smooth muscle.
 pregnancy-related increases in circulating cortisol may
produce anti-inflammatory effects.

11. Potential Risks from Maternal Asthma
Maternal Complications Fetal Complications
•Preeclampsia
•Hypertension
•Toxemia
•C-section placenta previa
•Hyperemesis gravidarum
•Perinatal mortality
•Intrauterine growth
retardation
•Premature birth
•Low birth weight
•Neonatal hypoxia
Ann Allergy Asthma Immunol 2005;95;234-8

12.  Nonadherence with controller therapy,
 Viral infections, Obesity.
 Diaphragmatic elevation of up to 4cm.
 Increased prostaglandin F2 may promoteα
bronchoconstriction,
 Asthma triggers .
 Gastroesophageal reflux.
 Increased emotional stress
 Increased progesterone levels result in centrally
mediated hyperventilation, manifested as ‘dyspnea of
pregnancy
Risk factors for exacerbations of asthma during
pregnancy

13. FETAL SEX
 Women pregnant with female fetuses
experience more severe asthma symptoms
than women pregnant with male fetuses
 the female fetus alters maternal asthma by
upregulating maternal inflammatory pathways.
 It has been postulated that the surge in androgens
at 12–16 weeks’ gestation produced by male
fetuses has a protective effect on maternal asthma.

14. Diagnosis and monitoring OF asthma:
1. If first symptoms occur during
gestation: spirometry
2. Testing bronchial hyperresponiveness is
contraindicated during pregnancy .
3. Skin prick tests are not recommended .
4. blood tests for specific IgE antibodies to
suspected allergens may be evaluated

15. Treatment
Educational topics forasthmatic pregnant
Stop smoking :
Use of inhaler devices
Adherence to treatment
Environmental control
Self-treatment action plan

16. Infections
 Respiratory infections are accounting for
about 60% of all asthma-related hospital
admissions.
 Viral infections are commonly associated
with asthma exacerbations and should be considered in
all patients experiencing exacerbations.
 influenza vaccination should be offered during the
influenza season

17. Management of Acute
Asthma in Pregnant Women
 Oxygen supplementation
 ntravenous fluid hydrationİ (if necessary)
 Inhale salbutamol (every 20 mins up to three doses in
the first hour)
 Ipratropium bromide (500μg)
 Systemic corticostreoids either intravenously or
orally (in moderate/severe cases)
 IV aminophylline NOT generally recommended
 IV Mg sulfate may be beneficial
 Concomitant hypertension
 Premature uterine contractions

18. Steps of asthma maintenance therapy during
pregnancy
LABAM. Schatz, M.P. DombrowskiAsthma in pregnancyNEJM, 360 (18) (2009), pp. 1862–1869
step Preferred controller medication Alternative controller medication
1 None–
2 Low-dose inhaled corticosteroid LTRA, cromolyn, theophylline
3 Medium-dose inhaled corticosteroid Low-dose inhaled
corticosteroid + LABA or LTRA
or theophylline
4 Medium-dose inhaled
corticosteroid + LABA
Medium-dose inhaled
corticosteroid + LTRA or
theophylline
5 High-dose inhaled
corticosteroid + LABA–
6 High-dose inhaled
corticosteroid + LABA + oral
corticosteroid–

19. Medication safety in pregnancy
 FDA Pregnancy Risk Classification for Drugs:
 Category A No risk demonstrated in 1st trimester
in controlled studies in women, no risk in later
trimesters
 Category B No risk in animal studies, but controlled
studies in women not done
 Category C Fetal harm in animals, no studies in
women (or studies in animals & women not available)
 Category D Evidence of human fetal risk, but
benefits > risk in life-threatening situations
 Category X Contraindicated in pregnant women

20. drug FDA category
BUDESONIDE B
CROMOLYN B
NEDOCROMIL B
MONTELEUKAST B
ZAFIRLEUKAST B
TERBUTALINE B
IPRATROPIUM B
BECLOMETHASONE C
FLUTICASONE C
ALBUTEROL C
THEOPHYLLINE C
SALMETEROL C
FORMOTEROL C

21. Potential Adverse Effects of Common
Asthma Drugs on the Fetus
Drug class Effect on fetus
Theophylline incresed HR, vomiting agitation,
when maternal levels > 12 mcg/mL
Systemic b2 Agonists incresed fetal HR & neonatal HR,
tremor,
LT modifiers not known, animal data
Decongestants Uterine vasoconstriction, fetal
gastroschisis
Corticosteroids preeclampsia, preterm and low birth
weight, cleft palate 1st trimester
(incidence 0.3%)

22. Medications to be Discouraged in
Pregnancy
 Frequent injections epinephrine (category C)
 Oral decongestants in the first trimester
 Iodine-containing cough medications
 Tetracycline (category D)
 Beta-blockers
 Prostaglandins

23. Immunotherapy During Pregnancy
 No advers effects on pregnancy outcomes
 Anapylaxix may a risk for mother and baby
Recommendations
 Do not begin immunotherapy during
pregnancy
 Carefully continue ongoing effective
immunotherapy (avoid systemic reactions)

24. Asthma attacks during labour :
 very rare because of high levels of cortisone &
adrenaline. Reliever inhalers can be used effectively
 Precautions against Latex allergy are necessary if
present
 Local anaesthetic is preferred.

25. Asthma and Lactation
 There is no effect of
lactation on maternal
asthma
 Prednisone, theophylline,
antihistamines, ICS,
SABAs, LABAs and
cromolyn are not
contrendicated.
 Theophylline may cause
neonatal irritability,
feeding difficulties.

26. Baby Asthma development
 Smoking
 Both parents are asthmatics
 If only one,it is the mother rather
than the father
 Leuckotriene antagonists pre –
pregnancy can control asthma during
pregnancy

27. Take home message
1. Rule of thirds.
2. Interplay between hormonal, immunological
& respiratory factors
3. Immune tolerance to protect the fetus
decreases immunity to viral infection&
increases allergic response
4. Respiratory infections account for 60% of
all asthma-related hospital admissions.
5. Uncontroled asthma may negatively affect
both mother and fetus
6. Medication safety should be considered .