Asthma in Pregnancy - NEJM 2009.pdf - AInotes

clinical practicetential diagnoses include cough due to reflux orpostnasal drip, bronchitis, laryngeal dysfunction,hyperventilation, pulmonary edema, and pulmonaryembolism. 22,23 The demonstration of a reducedFEV 1 or ratio of FEV 1 to forced vital capacitywith a 12% or greater improvement in FEV 1after the administration of inhaled albuterol confirmsa diagnosis of asthma in pregnancy. 23,24Methacholine testing, which is used to confirmbronchial hyperreactivity in patients with normalpulmonary function, is contraindicated duringpregnancy because of the lack of data on the safetyof such testing in pregnant patients. Thus, womenwith a clinical picture that is consistent withnew-onset asthma in whom the diagnosis is notconfirmed on the basis of testing for reversibilityof impairment in pulmonary function should betreated for asthma until methacholine testing canbe performed post partum if indicated. 23 Exhalednitric oxide has not been studied as a diagnosticmeasure of asthma in pregnant women.Patients with persistent asthma who have notpreviously been tested for allergies should undergoblood testing for specific IgE antibodies to allergenssuch as dust mites, cockroaches, mold spores,and pets. Skin tests are not generally recommendedduring pregnancy because skin testing withpotent antigens may be associated with systemicreactions.Current asthma control should be assessed accordingto the frequency and severity of symptoms(including their interference with sleep and normalactivity), the frequency of use of rescue therapy, thehistory of exacerbations requiring the use of systemiccorticosteroids, and the results of pulmonary-functiontests (Table 1). Spirometry is thepreferred method of assessing pulmonary function,but peak flow measurement is an acceptablealternative. FEV 1 and peak flow rates do notchange substantially as a result of pregnancy, 23 sothese measures can be used for assessing asthmacontrol in patients who are pregnant just as theyare in patients who are not pregnant. Patients whohave asthma that is well controlled and who arenot receiving controller medications can be classifiedas having intermittent rather than persistentasthma.Women who have previously received prescriptionsfor asthma medications should be askedabout their use in order to classify their currentlevel of therapy (according to a stepped-care approach,with step 1 indicating no treatment andstep 6 indicating the most aggressive treatment)(Table 2) and to assess potential problems withand barriers to adherence. Adherence to treatmentwith inhaled corticosteroids has been reported tobe poor in many studies. For example, the reportedadherence rate was approximately 50% in onestudy involving adults with asthma; decreased adherencewas associated with an increased frequencyof asthma exacerbations. 26 Women with asthmahave been reported to decrease their use of inhaledcorticosteroids during early pregnancy, ascompared with their use of these agents in the20 weeks before their last menstrual period 27 ; thismay be due to their reported concern regarding thesafety of inhaled corticosteroids during pregnancy.28 Moreover, a substantial proportion of asthmaticexacerbations during pregnancy have beenassociated with nonadherence to treatment withinhaled corticosteroids. 29 In addition to assessingadherence, asking about past medications andtheir effectiveness and any side effects can help toguide subsequent management decisions.Management of AsthmaAll patients should be educated regarding the relationshipbetween asthma and pregnancy, andthey should be taught about self-treatment, includinginhaler techniques, adherence to medication,and control of potential environmental triggers(Table 3). The appropriate management of commoncoexisting conditions that can aggravate asthma,such as rhinitis, sinusitis, and gastroesophagealreflux, can improve asthma control. Women whosmoke must be informed of the potential adverseeffects of smoking on the fetus, which may addto the fetal effects of uncontrolled asthma, 15 andshould be strongly encouraged to quit. Advice onenvironmental control measures for reducing exposureto allergens can be provided on the basisof the results of allergy testing (Table 4).Medications for asthma are divided into longtermcontroller medications that prevent the manifestationsof asthma (inhaled corticosteroids,long-acting β-agonists, leukotriene modifiers, cromolyn,and theophylline) (Table 5) and rescuetherapy that provides quick relief of symptoms(primarily short-acting inhaled β-agonists). Instudies involving patients who were not pregnant,inhaled corticosteroids were the most effectivecontroller medications in terms of reducing symptomsand exacerbations and improving pulmonaryfunction, and all controller medications have beenn engl j med 360;18 nejm.org april 30, 2009 1863The New England Journal of MedicineDownloaded from nejm.org at LSU HEALTH SCIENCES CENTER LIBRARY on January 18, 2011. For personal use only. No other uses without permission.Copyright © 2009 Massachusetts Medical Society. All rights reserved.