Dr. Jyotsna Joshi writes on management of asthma during pregnancy, labour, and postpartum, including recommendations on evaluation, treatment, and step therapy for asthma control in pregnant women.

Asthma is a common and potentially serious medical condition that complicates approximately 4 to 8% of pregnancies. In most cases asthma can be successfully controlled during pregnancy with little or no risk to the patient or her foetus.

---

Effect of asthma on pregnancy

Maternal asthma increases the risk of perinatal mortality, preeclampsia, preterm birth, and low birth weight. Low birth weight may be related to placental gene expression of inflammatory cytokines and placental 11 β hydroxysteroid dehydrogenase type 2 decreased activity resulting in increased placental cortisol concentration.

Women with severe or uncontrolled asthma are at higher risk for pregnancy complications and adverse foetal outcomes than women with well-controlled asthma. More severe asthma is associated with increased risks, while better controlled asthma is associated with decreased risks.

A higher frequency of caesarean section has been reported in asthmatic women as compared to the non-asthmatic. Recent evidence-based guidelines have concluded that it is safer for pregnant women with asthma to be treated pharmacologically than to continue to have asthma symptoms and exacerbations.

---

Effect of pregnancy on asthma

The “rule of thirds” applies to pregnant women with pre-existing asthma: approximately one third show worsening of asthma symptoms, one third experience improvement, and one third have no change in their asthma. Whereas, increase in bronchoconstricting substances (such as prostaglandin F2 α) may promote airway constriction, increase in free cortisol levels may protect against inflammatory triggers and increase in bronchodilating substances (such as progesterone) may improve airway responsiveness.

In addition, modification of cell-mediated immunity probably influences maternal response to infection and inflammation. In a prospective study Murphy et al have shown that respiratory viral infections were the most common precipitants of exacerbations (34%), followed by non-adherence to inhaled corticosteroid medication (29%). The condition is more likely to deteriorate in women with severe asthma (52 to 65%) than in those with mild asthma (8 to 13%). Exacerbations are most likely to occur between 24 and 36 weeks of pregnancy.

---

Management of asthma in pregnancy

Prompt diagnosis of asthma is essential to avoid delay treatment. Pregnant women with asthma must be evaluated (table 1), assessed for severity (table 2) and managed (table 3, 4) appropriately throughout pregnancy.

1. Optimising medication needs and response to therapy must be assessed frequently.
2. Pulmonary function may be evaluated by spirometry at least monthly.
3. Adequate patient education including self-management skills is important. Women who are educated about asthma management during pregnancy have better asthma control.
4. Patients must be monitored for asthma exacerbations and offered aggressive treatment for the exacerbations.

Classification of asthma (modified from GINA guidelines)

	Symptoms/day	Symptoms/night	FEV1
Intermittent	Monthly symptoms	No	≥80%, no PEF variability
Mild persistent	Weekly symptoms	Monthly episode	≥80% no PEF variability
Moderate persistent	Daily attacks symptoms	Weekly episode	60 to 80%
Severe persistent	Continuous symptoms	Frequent episode	≤60%

---

Recommendations for optimal asthma evaluation during pregnancy*

1. Clinical assessment of asthma includes subjective evaluations and pulmonary function tests.
2. Pulmonary functions must be tested by spirometry during outpatient visits or peak expiratory flow (PEF) monitoring with peak flow meters.
3. For women with moderate or severe asthma during pregnancy, ultrasound and antenatal fetal testing should be considered.
4. Asthma self-management skills, which include recognition of signs of worsening asthma, PEF monitoring, inhalers techniques, and treatment compliance.

---

Treatment recommendations for optimal asthma control during pregnancy*

1. The main goal of asthma treatment during pregnancy is to prevent hypoxic episodes in the mother and thereby maintain sufficient fetal oxygenation.
2. Use the step-care therapeutic approach as per asthma severity.
3. It is safer for pregnant women with asthma to be treated with asthma medications than to have asthma symptoms and exacerbations.
4. Controlling or avoiding exposure to tobacco smoke and other allergens and irritants can improve maternal well-being and reduce the need for medication.
5. Use of prednisone, theophylline, inhaled corticosteroids, beta2-agonists and antihistamines during breast-feeding is not contraindicated.

---

---

Avoiding allergens and irritants, such as tobacco smoke, that exacerbate asthma can improve maternal well-being and lessen the need for medication. Asthmatic women are advised to identify triggers and do what they can to reduce them at home. Specific measures to reduce mold, dust mite exposure, animal dander, cockroaches, and other environmental triggers may be necessary.

Asthma trigger avoidence

Asthma attacks or worsening of asthma symptoms, can occur after exposure to factors known as triggers. One of the best ways to identify asthma triggers is to pay careful attention to the pattern of asthma symptoms. For example, if symptoms occur primarily at home, allergens in that environment may be involved. If symptoms flare in the spring or fall, an outdoor allergy, such as tree or ragweed pollen, respectively, is more likely to blame.

The most common indoor allergens that affect asthmatics include:

1. Dust mites: They are microscopic organisms that are present in most households. The highest concentrations of mites are in mattresses, but they may be found in other bedding, upholstered furniture, carpets, curtains, house dust, or any woven material if the humidity is high enough.

Measures that help limit exposure to dust mites include the following:

1. Create a physical barrier to the source of the mites by covering pillows and mattresses with plastic or another impermeable fabric cover designed for this purpose. Cotton covers are not useful for containing dust mites.
2. Decrease the population of dust mites in the home by washing bedding and pillows in hot water and detergent or drying them in an electric dryer on the hot setting once per week.
3. Remove carpets from the bedroom. Minimize the number of stuffed toys and wash them weekly.
4. Control humidity. Mites thrive in humid environments. Opening windows in dry climates and using air conditioning in humid ones decreases humidity in the home and reduces the number of mites.
5. Using a mop or vacuum instead of a broom to clean the floor and surfaces may reduce exposure to aerosolized dust.

2. Mold: Mold spores can be found indoors in damp environments and trigger symptoms of asthma and allergic rhinitis in mold-allergic patients. Areas such as air conditioning vents, water traps, refrigerator drip trays, shower stalls, leaky sinks, and damp basements are particularly vulnerable to mold growth. To reduce the growth of mold, it is necessary to remove existing mold and reduce humidity to prevent future growth of mold. Humidity can be reduced by removing sources of standing water and persistent dampness. Specific measures include removing house plants, fixing leaky plumbing, correcting sinks and showers that do not drain completely.
3. Animal danders: Animal dander is made up of the dead skin cells that are constantly shed by animals. Asthma can be triggered by proteins from the "dander," saliva, and urine of common house pets, such as cats and dogs. Avoiding pets is recommended.
4. Cockroaches: Insects like cockroaches can shed or excrete particles that contain allergens that have been shown to trigger asthma in sensitive individuals. Regular pest control is crucial.

---

In addition allergic rhinitis (AR), gatro-esophageal reflux (GER) and other co morbidities must be assessed for and treated adequately. AR may be treated as per the international consensus panel, ARIA (Allergic Rhinitis and Its Impact on Asthma), which has developed a classification similar to the classification of asthma, and has recommended a stepwise approach to AR treatment based on the severity and duration of symptoms.

Allergic rhinitis is divided into 2 areas (intermittent and persistent disease):

Patients with intermittent disease have symptoms for less than 4 days/week and less than 4 weeks/year, whereas patients with persistent disease have symptoms for more than 4 days/week for more than 4 weeks/year.

1. Drugs; oral or topical antihistamines, and topical steroids are recommended for treatment of AR.
2. Patients should be treated with a stepwise approach, using increasingly powerful therapy for symptoms of increasing severity. This approach is also advisable when caring for pregnant patients with AR.
   1. Mild GER symptoms improve with lifestyle modification like eating smaller meals, not eating within a few hours of bedtime, elevating the head of a bed, avoiding foods that trigger reflux.
   2. For more severe GER symptoms the benefits versus the risk of drug therapy may be discussed with the patient. Unlike the non-pregnant patient, step-up therapy is preferred and proton-pump inhibitors (PPIs) reserved for the women with well-defined complicated GER not responding to lifestyle changes, antacids or histamine2-receptor antagonists (H2RAs). Based on product information from the manufacturers; the newer PPIs (rabeprazole, pantoprazole and esomeprazole) have been shown safe in various animal studies. The physician must encourage smoking cessation at every visit.
3. Flu vaccination must be deferred until after 12 weeks of pregnancy.

---

Management of asthma during labour and postpartum

Labour and delivery are not usually affected by asthma, but prospective studies have shown that 10-20% of women experience an exacerbation during labour. The drugs should be continued and adjusted according to need during this period. If systemic corticosteroids have been taken within previous months, give stress dose of corticosteroids, 50-75 mg a day of hydrocortisone equivalent for one to two days.

Avoid bronchoconstrictor agents for management of labour (such as prostaglandin F2 α) or for postpartum haemorrhage (such as ergonovine, methylergonovine and carboprost). In combination with adequate hydration, lumbar epidural analgesia to provide adequate pain relief and to reduce oxygen consumption and minute ventilation, and optimum medications asthma symptoms can be kept under control. Even acute exacerbation of asthma rarely requires caesarean delivery because most women respond to aggressive medical management.

---

---

The postpartum period is not associated with an increased rate of asthma exacerbations. However, use of asthma medications must continue after delivery and during breastfeeding. In women who experienced a change of severity during pregnancy, the severity reverts to pre-pregnancy level within three months after the birth. Few data are available on the safety of asthma drugs in breastfed neonates. Most drugs are considered to be safe, but irritability or sleepiness have been reported in the breastfed neonates of women taking theophylline and antihistamines. Non-steroidal anti-inflammatory drugs should be avoided in women intolerant to aspirin.

Source

*E, Boulet L-P. Asthma in pregnancy BMJ 2007; 334: 582-585.

**Global strategy for asthma management and prevention: Global initiative for asthma (GINA) guidelines, available at www.ginaasthma.com

Disclaimer- The views and opinions expressed in this article are those of the author's and do not necessarily reflect the official policy or position of M3 India.