ASK DIS: Asthma In Pregnancy and Lactation

PREGNANCY:

Inhaled beta agonists

Salbutamol and terbutaline are safe to use during pregnancy
Limited studies are available on long-acting beta agonists such as salmeterol and eformoterol, which are thus categorised as B3
As the majority of these studies analysed long-acting beta agonists in combination with other asthma drugs and have not shown any significant increase in harm
maternal plasma concentrations after inhaled salmeterol or eformoterol are very low or virtually undetectable.
The Asthma Management Handbook discourages starting treatment with long-acting beta agonists in the first trimester, but does not advocate withdrawing them if they are necessary to control the patient's symptoms

Inhaled corticosteroids

Using inhaled corticosteroids during pregnancy has been associated with a decreased risk of low birthweight babies.
A study of women with asthma exacerbations found a 55% reduction in subsequent exacerbations and hospital admissions in those who used beclomethasone compared to those who did not.
Women should be advised to continue their preventive drugs during pregnancy
Budesonide is a category A drug. The Asthma Management Handbook recommends switching to budesonide before pregnancy
Comparisons between different inhaled corticosteroids and doses are limited
The relationship between gestation and adverse events has not been explored in depth, but available studies suggest there is no greater risk with using inhaled corticosteroids in any particular trimester

Oral corticosteroids

Prednisolone, has been shown to be under-prescribed in acute asthma exacerbations during pregnancy, leading to persistent and recurrent asthma symptoms two weeks late
There have been reports of an increased risk of cleft lip with or without cleft palate from first trimester use, however, the data were from studies with a small sample size that included corticosteroid use for other conditions that generally needed higher and more frequent doses
It is also difficult to separate the potential effects of oral corticosteroids from the potential effects of poorly controlled maternal asthma as oral corticosteroids are generally indicated for severe asthma.
It is necessary to monitor blood glucose if oral corticosteroids are used in pregnancy, especially if there is gestational diabetes.

Cromolyns and leukotriene receptor antagonists

Inhaled cromolyns are probably safe to use in pregnancy.
No well-designed studies have assessed the sole use of leukotriene receptor antagonists, such as montelukast, during pregnancy.
Studies have shown an increase in adverse events with use, but these studies did not exclusively test montelukast during pregnancy
Montelukast should be used in pregnancy only if clearly indicated and only after considering more effective and safer treatment

Anticholinergics

Currently there are no published controlled data on the use of inhaled anticholinergics during pregnancy and their use should be reserved as a last option.
Nebulised ipratropium bromide with inhaled beta agonists and intravenous corticosteroids has been recommended for management of acute asthma during pregnancy

LACTATION:

Systemic absorption of inhaled drugs is generally minimal and causes little harm to the infant.
The infant's exposure is 10 to 1000 times less than during pregnancy.
The amount ingested through the mother's milk is far below the therapeutic level for an infant – mostly under 3% of a therapeutic dose per kilogram bodyweight

Montelukast

There are no human studies of montelukast in breastfeeding, but animal studies have detected excretion into milk.
Alternative treatment with short-acting beta agonists, long-acting beta agonists or inhaled corticosteroids should be considered during breastfeeding, particularly as montelukast is taken orally

Prednisolone

Prednisolone at recommended doses is thought to be safe since the amount excreted in human milk is low with daily doses up to 80 mg.
It is recommended to withhold feeds for four hours after each dose to reduce infant exposure.
Prednisolone is preferred over prednisone, as prednisone is converted to prednisolone in vivo, causing a double peak of parent medicine and metabolite

SUMMARY:

Short Acting Beta2 agonist, Long Acting Beta2 Agonist, Inhaled Corticosteroids, Oral and Intravenous Theophylline

Steroids PO can be used as normal in severe asthma
If Leukotriene Receptor Antagonists required to control the asthma, use is not contraindicated

REFERENCES:

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