Management Of Asthma In Pregnancy

Introduction
Asthma is the most common respiratory disorder affecting 3% of women of childbearing age. Pregnancy has a variable effect on asthma but for the vast majority of women there is no impact whatsoever.

The most common reason due to which asthma symptoms appear is that patients reduce their treatment because of a belief that the medication may be harmful. All commonly used medications
to control asthma are safe in pregnancy. All patients must be reassured that any flairs of their asthma must not be ignored and that treatment with medication such as steroids is safe both for themselves and for their fetus.

With regard to the effect of asthma on fetal outcome, there is no evidence that there is any significant impact on fetal growth or outcome.

Any patient whose asthma seems to be deteriorating, particularly in the third trimester, should be seen by an obstetric physician for review. It is obviously desirable that control of their asthma should be at its optimum prior to the onset of labor.

Management Of Asthma In Pregnancy
The best way to manage asthma is to avoid having an attack in the first place. 

Patient should be counselled to avoid exposure to her asthma triggers. This would help in improving the symptoms and decreasing the need of medications. 

The treatment and medicines are almost the same for pregnant woman as well as non pregnant asthma patients.

Management of Acute Asthma

• Pregnant women with asthma should be considered to be high-risk patients, and their management requires a close monitoring by the physician as well as an obstetrician.
• Evaluation in the emergency department and treatment of the pregnant asthmatic patient is almost the same as in the nonpregnant state, with some modifications.
• If arterial blood gases are obtained, it should be remembered that a pregnant woman usually has a baseline compensated respiratory alkalosis. Therefore, worsening of the alkalosis as a result of asthma exacerbation may lead to fetal hypoxia.
• In third trimester it is important to examine the patient either in sitting position or in a supine position with a left or right tilt and the uterus displaced to avoid the supine hypotensive syndrome.
• Oxygen supplementation should be given to maintain oxygen saturation at 95%.
• Fluid status should be carefully assessed, and intravenous fluid hydration should be administered if necessary.
• The initial treatment should include the administration of inhaled albuterol every 20 mins, up to three doses in the first hour. 
• Ipratropium bromide (500 g) may be concomitantly administered in severe cases. 
• Systemic corticosteroids, either intravenously or orally, should be given to patients who show no improvement with the initial bronchodilator therapy and to those with moderate to severe exacerbation.
• Patients should be reassessed closely to monitor response to therapy. This includes continuous fetal heart rate monitoring in those women at a gestational age of more than23 weeks. 
• The decision to hospitalize the patient or discharge home is based on the response achieved in the first 4 hrs in the Emergency Department. 

Management Of Chronic Asthma

• Almost all anti-asthma drugs are safe to use in pregnancy and during breastfeeding. 
• 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
• 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.
• During pregnancy, inhaled corticosteroids are the mainstay for long-term control. 
• Long-term medications are sometimes combined into single preparations, such as an inhaled steroid and a long-acting beta-agonist.

Inhaled corticosteroids: Corticosteroids prevent symptoms by preventing the swelling and mucus secretion that go along with inflammation. They help prevent severe asthma attacks. They are the most popular long-acting asthma drugs for pregnant women because they work well and are considered to be safe in pregnancy. They cause few side effects. 

Examples include budesonide (Pulmicort) and beclomethasone ( Beclovent).

Leukotriene inhibitors: These drugs work by blocking a substance that is produced by cells in the body (leukotrienes) that causes swelling and spasm of airways. These drugs are considered safe during pregnancy, but in general they do not work for as many people as inhaled steroids. 

Examples are montelukast , zafirlukast , and zileuton 

Long-acting beta-agonist inhalers: These medications often are used in combination with inhaled steroids for severe or nighttime symptoms. They also are used to prevent exercise-induced asthma. Since their action is delayed, they are not used for acute treatment . 

Examples of long-acting beta-agonists include salmeterol(Serevent) and formoterol.

Methylxanthines: These medications relax the airway walls. They have been linked to preterm labor, but in general they are thought to be safe in pregnancy. They are not used as much as the other long-term medications because they don't work for as many people. 

The most widely used example is theophylline . Because pregnancy can change the concentration of this medication in the bloodstream, checking levels of theophylline may be required.

Managing Labor In Patients With Asthma

Patients presenting in labor should be managed with an agreed protocol ( as decided by the hospital physicians). However, it is unusual for labor to be complicated by attacks of asthma and this is probably due to the increased secretion of cortisol during the process. 

However, attacks of asthma during labor can be managed by usual acute treatment, such as inhaled beta-sympathomimetics.

Patients who have been on maintenance glucocorticoids, for example, Prednisolone doses in excess of the equivalent of 5 mg Prednisolone daily, require hydrocortisone cover during labor. 

If an operative delivery is required, epidural anesthesia is preferable to general anesthesia but if a general anesthetic is required, the anesthetic care is the same as if the patient was not pregnant. 

Patients with severe asthma should be delivered in centers where appropriate backup facilities and medical expertise is available.

Acute asthma is still a cause of maternal death and as such must be taken extremely seriously.