Many pregnant women are completely reasonably trying to avoid taking medications during pregnancy. But it is necessary to treat asthma: harm that severe uncontrolled disease course cause and hypoxia (lack of oxygen supply to the fetus) are much greater than possible side effects of medications. Not to mention that asthma exacerbation creates a huge risk for woman’s life. But instructions for any medication contain contraindications, limitations or special conditions of their use during pregnancy. What to do?
First of all, treatment for a pregnant woman must be prescribed by a doctor. Close contact with a specialist is a necessary condition for successful treatment: it is the only way to achieve maximum effect with minimum risk. All medications are prescribed according to the principle: «only if the expected benefits outweigh the potential risk for mother and fetus.» Especially stringent requirements are imposed on the first trimester of pregnancy period as the most vulnerable to any impacts.
During asthma treatment topical (localized) inhalation drugs are preferable since their concentration in blood is minimal and local effect in the target area — bronchi – maximal. It is recommended to use inhalers containing freon. Pressurised metered dose inhalers should be used with a spacer to reduce risk of side effects. Prerequisite for successful treatment is proper inhalation technique. Pulmonologist or instructor in Asthma-school can help to acquire necessary skills.
It is stated that regardless of course severity asthma is a chronic inflammatory disease. It is a permanent presence of this specific chronic inflammation in the bronchi that causes symptoms. If you treat only symptoms (reduce bronchismus), but not eliminate their cause, the disease will progress. Therefore, the treatment consists of:
- basic therapy (drugs to control disease), aimed to control inflammation;
- medications to relieve symptoms and treat exacerbations.
Basic therapy is appointed by a doctor depending on the asthma course severity. Accurate basic therapy significantly reduces the risk of exacerbations and minimizes the need for medications to relieve symptoms.
About Drug Administration Safety During Pregnancy
Nowadays, medicine has become evidence-based, i. e. every recommendation, every concept, every drug before approval and permission to be used must pass tests according to certain scientific rules. A medicine is considered completely safe only when its safety is tested and proven in the so-called double-blind randomized placebo-controlled large-scale clinical researches which compare this drug effects with both known drugs and no intervention. This study is constructed so that doctor’s or patient’s beliefs or prejudices could not affect final conclusions. But these studies among pregnant women are almost impossible for ethical reasons. Drugs safety has to be checked on animals and on long-term pregnancy outcome observations among humans. Therefore, no drug used for asthma treatment was assigned with the highest degree of safety – «A» category ( «safety on placebo level», indicating that the drug affects the safety indicators no more than if the drug is not used).
All drugs are assigned to a certain category of safety for pregnancy period. Unfortunately, this is usually not specified in instructions to drugs. Thus, «A» category of drugs currently exists. The following safety category, «B» category is assigned to drugs that are proven to be safe in animal studies or, even if tests on animals revealed a side effect, it was confirmed that drugs are safe for people even during vulnerable pregnancy periods. If the potential benefit of administration exceeds risks of complications or safety data are simply not enough, the drug gets «C» category. «D» Category includes drugs that are proved to have side effects, but potential benefits allow their use despite the risk. «X» Category – drugs with teratogenic effects, the risk of their use exceeds the possible benefit, and during pregnancy, they are not applied.
Symptoms Relief Drugs
A pregnant woman should not ignore asthma attack as lack of oxygen in the blood can damage fetus development. This means that drugs to relieve symptoms are needed. Drugs of choice are inhaled beta2-agonist with a rapid onset of action. Selective drugs locally affecting bronchi with minimal impact the on cardiovascular system.
The use of these drugs during pregnancy requires care and medical supervision. Restrictions, first of all, are connected with the fact that injectable beta2-agonists preparation cause uterus muscles relaxation, which leads, at the threat of miscarriage during the 1st and 2nd trimester of pregnancy, premature separation of the placenta, hemorrhage and toxicosis during the 3rd trimester, to increased bleeding. At inhaled formulation in the recommended dosage, the effect on uterus muscles is very small, but this theoretical possibility is considered. Uncontrolled use of bronchodilators during late pregnancy is able to lengthen labor duration.
Fenoterol is conterindicated during the first trimester of pregnancy, but can applied if expected benefits exceed potential risks. The studies showed no negative impact on pregnancy course, but available data are insufficient to remove restrictions. For inhaled anticholinergics, no negative effects on fetal development are revealed ( «B» category), but this drug is not usually used to treat asthma (only in combination), because its action develops more slowly.
During pregnancy, it is absolutely contraindicated to use any ephedrine drug as ephedrine causes the uterus to blood vessels narrowing and worsens fetal hypoxia. Adrenaline at asthma exacerbations is also not recommended.
The frequency of bronchodilators use is an important asthma control indicator. If the necessity of their application increases you should consult a pulmonologist to intensify your planned (basic) therapy to control the disease. Treatment with only medications to relieve symptoms is acceptable only in very mild cases with rare and not severe symptoms and no severe exacerbations. These medications may relieve already existing symptoms but do not have anti-inflammatory activity and does not affect the disease control.