Many women who have asthma are worried about pregnancy, in case it might affect their asthma adversely or bring harm to their baby. Hence management of asthma during pregnancy is a challenge as we must maintain a balance between maternal health benefits from drug and potential toxicity for the growing foetus.
Effect of Pregnancy on Asthma
Meta-analysis evaluating retrospective and prospective studies showed that one third of women have improvement of asthma during pregnancy, one third experience no change, and one third have worsening of their asthma. Severe asthmatics, even those under good medical control before pregnancy, are more likely to experience severe exacerbation during pregnancy.
Women who have more severe asthma tend to have exacerbations of their disease with more symptoms and medications required than in women who have milder disease. The first trimester is generally tolerated well. If symptoms worsen, it usually occurs in the second and third trimesters, with the peak in the sixth month regardless of the severity of asthma. Generally, there is improvement in the last 4 weeks of pregnancy. During labour and delivery, only 10% to 20% have symptoms. These symptoms tend to be mild and can be controlled. The incidence of asthma symptoms during labour and delivery increases with increased asthma severity. Asthma tends to return to the prepregnant state within 3 months post-partum. Successive pregnancies tend to have a similar course.
Physiological changes during pregnancy may affect the course of asthma. Certain hormone like progesterone may improve asthma. Others like decreased functional residual capacity due to the elevation of diaphragm from expanding foetus, increased upper airway resistance from nasal turbinate congestion and increased gastroesophageal reflux may worsen asthma.
Other factor that affects asthma include the reluctance of doctor to treat resulting in poor control of asthma. In addition, there is a decrease in compliance because of patient’s concern about the safety of medications for the foetus.
Pregnant women appear to be particularly susceptible to the effects of viral respiratory infections, including influenza. The annual flu shot is recommended for pregnant women with asthma. It is given during the second or third trimester.
Effect of Asthma on Pregnancy
Conclusions from 8 prospective studies of the effects of asthma on maternal and perinatal outcomes showed that mild to moderate asthma during pregnancy can have excellent outcomes. There may be an increase in preterm delivery at less than 37 weeks gestation among subjects who had severe asthma or who required oral steroids during pregnancy. Some studies reported an increase in preeclampsia in patients who had daily symptoms. There may be an increased risk of small for gestational age in the group with uncontrolled asthma.
Active and good asthma management with your Lung Specialist is recommended for good pregnancy outcomes.
Safety of Asthma Medications in Pregnancy
Long Term Control Medicines
Inhaled steroids prevent and reduce swelling in the airways and decrease mucus production. They are the most effective long term control medicine available. They improve asthma symptoms and lung function. They must be taken on a regular basis and are safe to use during pregnancy. Common inhaled steroids are budesonide, fluticasone and beclomethasone. They are safe for the pregnant mother and foetus.
Singulair is a long-term control medicine. They are effective at improving asthma symptoms and lung function, but not to the same extent as inhaled steroids. Safety studies have shown that it does not increase health risk for both mother and child.
Quick Relief Medicines or Short-acting beta-2 agonists
Quick -relief medicines are used to relieve asthma symptoms or attack. Common inhaled beta-agonists include Ventolin and ipratropium. Available studies have shown that short-acting beta-agonists are safe for pregnant mother and her baby. They have been used by pregnant mother for decades. These studies did not show any increased risk for major birth defects, preterm delivery, low birthweight or preeclampsia.
Long-acting beta-2 agonists
Since 1993, two long-acting inhaled bronchodilators have become available – salmeterol and formoterol. Their pharmacologic and toxicologic profiles are similar to the short-acting beta-agonists. As a group, no increased risks for preterm delivery or low birthweight were associated.
Your Lung Specialist may have given you a short burst of oral steroids if you have severe asthma symptoms. This may prevent a visit to the emergency unit. The steroid is very effective at reducing the airway inflammation. The steroid burst should be discontinued as soon as possible.
There is some concern about the use of oral steroid resulting in preeclampsia, low birth weight, preterm delivery and oral clefts especially when given during the first trimester. However, in these studies, the length of exposure, the dose, and the timing of oral administration were not well documented. Severe asthma has been associated with maternal and foetal mortality, so risk-benefit consideration favours the use of oral steroid when indicated during severe excerbations.
Management of Asthma during Pregnancy
The general principles of asthma management during pregnancy do not differ substantially from the management of non-pregnant asthmatics. The main goal is to have no limitation of activity, minimal symptoms, no exacerbations, normal lung function and minimal adverse effects of medications. It is the job of the Lung Specialist to provide optimal therapy to maintain control that improves maternal quality of life and allows for normal foetal maturation.
Assessment and monitoring
The Lung Specialist should monitor and assess the asthma control on a monthly basis. Pregnant asthmatics, even those who have mild or well controlled disease need to be monitored during the pregnancy. Home peak flow monitoring is a valuable tool in managing the pregnant asthmatics with moderate to severe asthma.
Avoidance of asthma triggering factors
Avoidance of asthma triggers is important because exposure may lead to increased asthma symptoms and the need for more medication. Smoking should be discouraged strongly, and all patients should try to avoid environmental tobacco smoke exposure as much as possible.
Patient education is more important than ever in pregnancy. She must understand the potential adverse effects of uncontrolled asthma on the well-being of the foetus. Treating asthma with medications is safer than increased asthma symptoms that may lead to maternal and foetal hypoxia. She should be able to recognize symptoms of worsening asthma. Correct inhaler technique must be reinforced.
Your Lung Specialist should use a stepwise approach in achieving and maintaining asthma control. The number and dose of medications used are increased as necessary and decreased when possible. Decreasing the dose should be done carefully as it may lead to an exacerbation of symptoms. It may be prudent to postpone attempts at reducing therapy that is controlling the asthma until after the infant’ birth.
Management of asthma during labour and delivery
Only approximately 10 - 20% of women develop an exacerbation of asthma during labour and delivery. Asthma medications should be continued during these periods. Remember to bring your own medicine to the hospital, so that your doctor and nurses know the current medication and dosage prescribed by your Lung Specialist. If systemic steroid has been used in the previous month, it should be administered during labour to prevent maternal adrenal crisis. We should be aware of the potential side effects that labour medications may have on asthma causing bronchospasm. Usually, the attack can be managed medically, and it is rarely necessary to perform emergency caesarean.
Management of asthma during lactation
Most of the medications are not contraindicated during breast feeding. They do not affect your baby or interfere with your milk production. Management of asthma during lactation is the same as during pregnancy. Inhaled drugs are preferred. Your bloodstream absorbs less medicine with inhaled medicine; therefore, less medicine passes into the breastmilk. Medication exposure to the infant can be decreased by nursing prior to taking asthma medication. Even drugs taken orally will only be secreted in small quantities and will not upset the baby. Theophylline passes through breast milk in trace amounts. This has been associated with irritability and insomnia in some infants. However, this medication is hardly used.
Asthma is a common condition which causes few if any problem in pregnancy. However, it must be under control to achieve excellent maternal and foetal well-being. Exacerbations and poor symptom control are associated with worse outcomes for both the baby (pre-term delivery, low birth weight, increased perinatal mortality) and the mother (pre-eclampsia). Although there is a general concern about any medication use in pregnancy, the advantages of actively treating asthma in pregnancy markedly outweigh any potential risks of usual controller and reliever medications. Hence make sure you go for regular follow up with your Lung Specialist.