Asthma and pregnancy

Asthma and pregnancy

The risks of uncontrolled asthma are far greater than the risks to the mother or fetus from the medications used to control asthma.

Pregnant women are breathing for two It is important to have the asthma under good control: breathing difficulties in the mother affect the fetus by compromising the oxygen supply.

When asthma is controlled, women with asthma have no more complications during pregnancy and giving birth than non-asthmatic women. However, uncontrolled asthma during pregnancy can produce serious maternal and fetal complications.

Uncontrolled asthma is associated with complications such as:

premature birth

low birth weight

maternal blood pressure changes (i.e. pre-eclampsia)

In general, 1/3 of women have a decline in their asthma status, 1/3 have improved asthma health, and 1/3 remain unchanged during pregnancy.

Most asthma medications are safe during pregnancy. It is important to keep in mind, that the first form of therapy for asthma during pregnancy should be the avoidance of allergy triggers and other non-allergic triggers of asthma.

Good Control of Asthma

Asthma is under good control if the expectant mother is:

active without experiencing any asthma symptoms

sleeping through the night, and not waking due to asthma symptoms

attaining her personal best peak flow number. This is an important indicator as it is an objective assessment measure.

Episode Prevention

Acute episodes endanger the fetus by reducing the oxygen it receives. It is therefore important to prevent an episode during pregnancy or the birth process.

Some ways this can be done include:

controlling your environment: avoid triggers and causes (see also Environmental Control in the Asthma Management presentation) As noted above, avoidance of triggers should be the first form of asthma therapy during pregnancy.

continuing regularly scheduled medications during pregnancy and labour and delivery.

The expectant mother should be aware of the following:

Influenza vaccine - can be given after the first 3 months of pregnancy. The influenza vaccine is recommended for people who have identified viral infections as one cause of their asthma. It is not recommended for people with an egg allergy.

Exercise - bronchospasm commonly occurs following vigorous exercise and lasts for 30 - 60 minutes. Pregnant women with asthma should exercise, under the supervision of their physician. Exercise-induced bronchospasm can be avoided or reduced by:

taking medication before exercise (such as Ventolin® or Intal®)

including a warm-up and cool down as part of the exercise

wearing a scarf over the mouth and nose if exercising in the cold air.

Smoke - The unborn baby may be exposed to environmental tobacco smoke or second hand smoke from either the mother or father. This exposure may have adverse effects. Infants are 3 times more likely to die of Sudden Infant Death Syndrome (SIDS) if their mothers smoked during or after pregnancy. A pregnant woman who smokes runs a greatly increased risk of having a severe asthma episode at some time in the pregnancy. This could seriously reduce the oxygen supply to the fetus, especially if the blood of the fetus already contains a large amount of carbon monoxide gas from cigarette smoke. An average reduction in birth weight of 120g (4oz) per pack of cigarettes smoked per day by the father has been reported.

Asthma Medications and Pregnancy

The known risks of uncontrolled asthma are far greater than the known risks from asthma medications to both mother and fetus.

Asthma care should be integrated with obstetric care. The same health care provider if possible should be used for both. A team approach should be used if more than one clinician is involved.

The aim of good control is achieved via an asthma continuum. This includes increasing the number of medications and frequency of administration as necessary to establish control, and decreasing when possible to maintain control.

Monitor asthma status continually, in every prenatal visit. This can be done through objective lung function tests.

Objective Assessment Measures

Objective assessment measures are important because many changes are associated with pregnancy and some changes are due to asthma. Objective measures are essential for assessing and monitoring the asthma in order to make appropriate medication changes.

The pregnant woman can expect:

office spirometry

peak expiratory flow rate can be measured with peak flow metres, especially for those who take medications daily

Both are indicators of airway obstruction. These measurements do not change with pregnancy.

The goal is to try and maintain normal, or near normal pulmonary function rates.

Assessment measures for the fetus include:

ultrasound - to provide early indication of fetal growth. A gel is put on the abdomen, and a hand-held sensor provides an image of the fetus which is projected onto a computer screen.

electronic fetal heart rate monitoring - a doppler is used to hear the fetal heart rate through the mothers abdomen.

nonstress test - can be used to assure fetal well-being. These tests monitor the fetal heart rate over a period of time.

daily kick charts - are used to monitor fetal activity. The mother keeps a record of when she feels the fetus kick or move. The charts can be compared over a period of time to see the fetus activity pattern.

Episode Management

How to manage an asthma episode:

Prevention is the key. Avoid the triggers if possible.

Early treatment is important to manage an asthma episode. Take the reliever medication when your first signs appear. Use what worked well in the past.

It is important that pregnant women do not delay in getting further medical treatment if any of the following occurs:

the medication does not provide rapid improvement

the improvement is not sustained

there is further deterioration

the episode is severe

there is a decreased amount of fetal movement

Remember, continue taking regularly scheduled medications.