Asthma in Pregnancy: Triggers, Management and Treatment Guidelines and Complications

Occurrence of Asthma in Pregnancy

Asthma is a chronic inflammatory pulmonary disorder that is characterized by reversible obstruction of the bronchioles. The occurrence of asthma in pregnancy needs special attention as it may adversely affect outcome of the pregnancy. It is better to prevent asthmatic attacks in pregnancy than just treating it, hence patient education on prevention and compliance to medication is important.

About 4 to 8% of pregnant women have asthma and about 1/3 of these asthma cases remain stable throughout the pregnancy period, and 1/3 worsen while the other 1/3 improve with time. Some studies have shown improvement in first few months, followed by relative worsening around 29th week of gestation and late pregnancy improvement.

About 35% of pregnant women with asthma are more likely to have an upper respiratory tract or urinary tract infection than other pregnant women without asthma.

How a boy or girl as a fetus affects asthma in pregnancy

Having a boy or girl can influence asthma in pregnancy. Analysis of asthma severity by comparing predicted and measured peak expiratory flow (PEF) in pregnant women with male fetuses had 10% improvement in airway changes as testosterone may potentiate beta-adrenergic relaxation of bronchial tissue and inhibits response to histamine whereas sex-specific factors related to female fetus may promote activation of inflammatory pathways and may worsen asthma in pregnancy.

Step therapy Treatment guidelines for Asthma in Pregnancy

  1. Mild Intermittent Asthma in pregnancy: In this, no daily medications required but albuterol as needed
  2. Management of Mild Persistent Asthma in pregnancy: Use of low-dose inhaled corticosteroid
  3. Management of Moderate Persistent Asthma in pregnancy: Low-dose inhaled corticosteroid and salmeterol or medium-dose inhaled corticosteroid or (if needed) medium-dose inhaled corticosteroid and salmeterol
  4. Severe Persistent Asthma in pregnancy: High-dose inhaled corticosteroid and salmeterol and (if needed) oral corticosteroid

FDA pregnancy risks category of medications used in treatment of asthma during pregnancy

  1. Albuterol – Category C
  2. Budesonide – Category B
  3. Salmeterol – Category C
  4. Fluticasone/salmeterol – Category C
  5. Oral corticosteroids – Category C
  6. Cromolyn – Category B
  7. Theophylline – Category C
  8. Montelukast – Category B

Drugs in category show no evidence of risk in humans, while drugs in category may have risks that cannot be ruled out.

Side effects of drugs used in treating Asthma during pregnancy

  1. There is increased incidence of Diabetes mellitus , preterm labor, and giving birth to low-birth weight infants due to the use of oral steroids in treatment of asthma during pregnancy especially in the 1st trimester (the first 3 months of pregnancy)
  2. Oral steroids show association with preeclampsia and pregnancy induced hypertension

Potential harm to the fetus is more likely to result from a severe uncontrolled asthma than from treatments.

What triggers Acute Exacerbation of Asthma in pregnancy?

  1. Potential viral infection are responsible for about 34% of asthma cases in pregnancy
  2. Non-adherence to inhaled corticosteroids accounts for about 29% of asthma attacks in pregnancy

Complications of Asthma in Pregnancy

  1. Hyperemesis
  2. Hypertension /pre-eclampsia
  3. Vaginal hemorrhage
  4. Complicated labor
  5. Intrauterine Growth Restriction (IUGR)
  6. Preterm delivery
  7. Increased perinatal mortality
  8. Neonatal hypoxemia

Differential diagnosis of Asthma in Pregnancy

  1. Physiological dyspnea of pregnancy
  2. Pulmonary edema
  3. Peripartum cardiomyopathy
  4. Amniotic fluid embolism