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Summary for primary care

British Guideline on the Management of Asthma in Pregnancy


This Guidelines summary is part of a series of summaries of the British Thoracic Society/Scottish Intercollegiate Guidelines Network Guideline 158: British guideline on the diagnosis and management of asthma.

This summary focuses on recommendations for the management of asthma in pregnant women, including during labour, and recommendations for breastfeeding mothers. For the complete set of recommendations, please refer to the full guideline.

Follow the links for summaries of BTS/SIGN recommendations on the diagnosis and management of asthma in the following groups:

Grades of Recommendation

The grade of recommendation relates to the strength of the supporting evidence on which the evidence is based. It does not reflect the clinical importance of the recommendation.

[A] At least one meta-analysis, systematic review, or RCT rated as 1++, and directly applicable to the target population; or a body of evidence consisting principally of studies rated as 1+, directly applicable to the target population, and demonstrating overall consistency of results.

[B] A body of evidence including studies rated as 2++, directly applicable to the target population, and demonstrating overall consistency of results; or extrapolated evidence from studies rated as 1++ or 1.

[C] A body of evidence including studies rated as 2+, directly applicable to the target population and demonstrating overall consistency of results; or extrapolated evidence from studies rated as 2++.

[D] Evidence level 3 or 4; or extrapolated evidence from studies rated as 2+.

Good-practice Points

[✓] Recommended best practice based on the clinical experience of the guideline development group.

For the full key of evidence statements and recommendations, refer to the full guideline.


The majority of women with asthma have normal pregnancies and the risk of complications is small in those with well-controlled asthma. Several physiological changes occur during pregnancy that could worsen or improve asthma, but it is not clear which, if any, are important in determining the course of asthma during pregnancy. Pregnancy can affect the course of asthma and asthma and its treatment can affect pregnancy outcomes.

Effect of Asthma in Pregnancy

[C] Monitor pregnant women with moderate/severe asthma closely to keep their asthma well controlled.

[B] Women should be advised of the importance of maintaining good control of their asthma during pregnancy to avoid problems for both mother and baby.

[✓] Advise women who smoke about the dangers for themselves and their babies and give appropriate support to stop smoking.

Management of Acute Asthma in Pregnancy

[C] In pregnant patients, give drug therapy for acute asthma as for non-pregnant patients including systemic steroids and magnesium sulphate.

[D] In pregnant patients with acute asthma, deliver high-flow oxygen immediately to maintain saturation 94–98%.

[D] Acute severe asthma in pregnancy is an emergency and should be treated vigorously in hospital.

[✓] Continuous foetal monitoring is recommended for pregnant women with acute severe asthma.

[✓] For women whose asthma is poorly controlled during pregnancy there should be close liaison between the respiratory physician and obstetrician, with early referral to critical care physicians for women with acute severe asthma.

Drug Therapy in Pregnancy

[C] Counsel women with asthma regarding the importance and safety of continuing their asthma medications during pregnancy to ensure good asthma control.

  • The following drug therapies should be used as normal during pregnancy:
    • [C] short-acting β2 agonists
    • [C] long-acting β2 agonists
    • [B] inhaled corticosteroids
    • [C] oral and intravenous theophyllines
      • [D] check blood levels of theophylline in pregnant women with acute severe asthma and in those critically dependent on therapeutic theophylline levels
    • [C] steroid tablets, when indicated for women with severe asthma. Steroid tablets should never be withheld because of pregnancy. Women should be advised that the benefits of treatment with oral steroids outweigh the risks
    • [C] if leukotriene receptor antagonists are required to achieve adequate control of asthma then they should not be withheld during pregnancy
    • [C] sodium cromoglicate and nedocromil sodium.

Management During Labour

[✓] Advise women that an acute asthma attack is rare in labour.

[✓] Advise women to continue their usual asthma medications in labour.

[✓] In the absence of an acute severe asthma attack, reserve Caesarean section for the usual obstetric indications.

[✓] If anaesthesia is required, regional blockade is preferable to general anaesthesia in women with asthma due to the potential risk of bronchospasm with certain inhaled anaesthetic agents.

[✓] Women receiving steroid tablets at a dose exceeding prednisolone 7.5 mg per day for more than two weeks prior to delivery should receive parenteral hydrocortisone 100 mg 6–8 hourly during labour.

[D] Use prostaglandin F2α with extreme caution in women with asthma because of the risk of inducing bronchoconstriction.

Drug Therapy for Breastfeeding Mothers

[C] Encourage women with asthma to breastfeed.

[C] Use asthma medications as normal during lactation, in line with manufacturers’ recommendations.