Asthma is one of the most common potentially life-threatening condition complicating pregnancy. The incidence of asthma is increasing steadily and it is estimated that asthma currently affects 4% to 8% of pregnant women. In rare cases asthma may occur for the first time during pregnancy. In general well controlled asthma is not associated with a higher risk of adverse pregnancy outcomes.

In fact the most common cause of worsening  asthma in pregnancy is due to noncompliance with medicines.

It is seen that about one third of the pregnant women with asthma experience worsening of their asthma symptoms during pregnancy.
One third of the asthmatic women feel better during pregnancy.

Asthma exacerbations are more frequent at the beginning of the third trimester of pregnancy and improves a few weeks before labor.

10 % of the pregnant women suffering from asthma seek emergency care during the pregnancy.

Oxygen is vital for the well being of the mother and the fetus. Every pregnant woman needs a proper treatment to maintain normal lung functions and oxygen level to maintain proper oxygen supply to the fetus.

Asthma patient should receive education about maintenance and rescue medication, how to measure PEFR by peak flow meter, proper use of inhalers, asthma prevention, and adherence of asthma action plan. Patient should also learn when the asthma is worsening and when to contact the doctor.

Spirometry is the preferred method for pulmonary function testing during outpatient visits. However, peak expiratory flow measurement with a peak flow meter is also adequate.

•  Pre eclampsia.

•  Placenta previa.

•  Gestational hypertension.

•  Prolonged hospital stay.

Fetal complications include:

• Increased risk of perinatal mortality

• Intra uterine growth retardation.

• Low birth weight.

• Neo natal hypoxia.

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• Mechanical obstruction

• Laryngeal obstruction

• COPD

• Pulmonary edema

• Pulmonary embolism

• Amniotic fluid embolism

• Upper airway cough (Rhinitis, sinusitis, reflux)

• Carcinoid syndrome.

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The American College of Obstetricians and Gynecologists (ACOG) has issued a practice bulletin for management of asthma during pregnancy. The new recommendations appear in the February issue of Obstetrics & Gynecology 2008. They are:

• Prevent hypoxic episodes in mother there by maintaining adequate fetal oxygenation.

• Monitor lung functions by Spirometry preferred.

• Avoid and controlling asthma triggers.

• Patient education

• Individualized pharmacotherapy to maintain normal pulmonary functions.

• Control day time and nocturnal symptoms.

• Maintain normal activity levels including exercise.

• Prevent acute exacerbations of asthma.

• No emergency department visit or hospitalization.

• Avoid adverse effects of medications to mother and child.

• Give birth to a healthy child.

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• Identify and control asthma triggers.

• Eliminate all exposure to tobacco smoke (active or passive).

• Take proper treatment of asthma.

• Ask for a written Asthma action plan from your doctor.

• Identify worsening of asthma and go for prompt treatment.

• Continue your regularly scheduled asthma medication during labor and delivery.

• PEFR of the patient should be measured regularly.

Patient should seek medical help in emergency department or hospital if any of the following occur:

1. If therapy does not provide rapid improvement.

2. Improvement is not sustained.

3. If there is worsening of asthma symptoms.

4. If asthma exacerbation is severe.

5. If fetal kick count decreases.

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Although asthma medication enter breast milk but their concentration is too small to produce any adverse effect to the baby. So it is safe to breast feed the baby during inhaled asthma medication.

Theophylline: 
Some studies have shown that theophylline can cause increased incidence of premature birth. When two medications are taken specially theophylline and oral steroid the risk of premature birth increases three fold.

But recent studies have given clean chit to theophylline but it is necessary to measure serum theophylline levels during pregnancy. Since protein binding decreases during pregnancy, this may result in increased free drug levels with normal doses. It is recommended to take theophylline in lower doses.

Beta2- adrenergic agonists: 
No adverse effect has been noted on fetus or infant on mother’s milk. For pregnant women with asthma, recommended rescue therapy is inhaled albuterol (Salbutamol).

Corticosteroids: 
Oral corticosteroid has shown to increase the risk of premature birth in some studies. This risk increases three fold when they are given with theophylline. Oral corticosteroids used by mother are not a contraindication to breast feeding.

Inhaled steroids are safe during pregnancy and lactation. For persistent asthma during pregnancy, first-line controller therapy consists of inhaled corticosteroids. During pregnancy, budesonide is the preferred inhaled corticosteroid. Though systemic absorption can occur, low plasma levels achieved by inhalation make it unlikely that fetal effects will be seen.

Anti cholinergic agents:
Ipratropium is used less frequently for asthma, but is devoid of any adverse effect.

Cromolyn sodium:
Animal and human studies suggest little potential for fetal harm.

Nedocromil sodium: 
There is not sufficient data for this new drug, which is similar to Cromolyn sodium.

Leukotriene receptor antagonist:
Leukotriene receptor antagonist like zafirlukast and montelukast are probably safe in pregnancy but use should be limited to special circumstances, where they are viewed essential for asthma control. Zileuton should not be used in pregnancy.

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A number of reports have appeared describing immunotherapy without apparent adverse effects on human pregnancy. Anaphylaxis during pregnancy is a potential risk for mother and fetus.
Patients already receiving immunotherapy and are near maintenance dose or are benefited by it are advised to continue immunotherapy. However it is generally advised not to begin immunotherapy during pregnancy.

Influenza vaccine is a killed virus vaccine. No adverse outcome to the fetus has been noted in two studies including 245 women.

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Tannic acid:
Tannic acid is some times used to denature environmental cat or dust mite antigen. There is no published data on exposure to this agent during pregnancy, so its better to avoid.

Benzyl benzoate:
Benzyl benzoate is an ascaricide used to clear dust mites from an environment. Teratogenicity tests have been negative in rats and mice. No human studies reported, it’s better to avoid.

Boric acid:
Boric acid is used as insecticide in eliminating cockroaches. Feeding boric acid to pregnant rats has not shown any adverse effect in the course of pregnancy or on fetus. An evaluation of 253 pregnancies with early exposure to boric acid was unable to identify a significant increase in the incidence of birth defects in the offspring.

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Though asthma is in most cases a heredity disease but not all the offspring of a asthmatic mother develop asthma. Smoking during pregnancy increases the likelihood of fetus developing asthma later on.

Asthma should in no way considered a contraindication to pregnancy, and when asthma is properly controlled, pregnant women with asthma can maintain a normal pregnancy with little or no increased risk to themselves or their fetus.

Acute asthma attack is very rare in labour due to endogenous steroid production. Asthma medication should be continued as usual during labour. Caesarean section should be reserved for acute severe asthma patients or patients with usual obstetric indications.

Studies and data suggest there is increased risk of postpartum exacerbation of asthma in women having Caesarean section. Many factors such as postoperative pain with diaphragmatic splinting, hypoventilation and atelectasis may be responsible for deteoration of asthma.

Also Caesarean section is planned in patients with severe asthma so chances of acute attack is higher after words.

Women with asthma are encouraged to breast feed. The safety of older asthma medications including steroid and  theophylline tablets has been documented in many studies.

Inhalers including steroids inhalers are also found to be safe during lactation.

Newer asthma medications should be used in line with manufacturer's recommendations.

Note: Please consult your doctor if you are having asthma and want to conceive or already pregnant. This article is intended to help you understand asthma and pregnancy  better but cannot replace doctors consultation.

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Last edited 30-7-2008