Table 1

 Summary of studies investigating the incidence of asthma exacerbations during pregnancy

StudyCountryYearStudy designAsthma (n)% hospitalised% ED visitsICS useSuspected causes of exacerbation
ED, emergency department; ICS, inhaled corticosteroid; OCS, oral corticosteroid.
Williams3UK1955–65Case seriesn = 23100%NilNasorespiratory infection
Gluck and Gluck4USACase seriesn = 4728%Nil
Melville et al5Jamaica and TrinidadCase seriesUnknownn = 8Unknown
Stenius-Aarniala et al6Finland1972–82Prospective cohortn = 19817%Some used ICS (up to a maximum dose of 400 μg/day)
Schatz et al7USA1978–84Prospective cohortn = 3301.8%10.9%10% used beclomethasone
Apter et al8USA1978–88Case seriesn = 2864%43%29% used ICSDiscontinuation of medication
Viral infection
Mabie et al9USA1986–9Case seriesn = 20042.5%13%Nil
Perlow et al10USA1985–90Historical cohortn = 8146%Unknown
Jana et al11India1983–92Prospective cohortn = 1828.2%Some used beclomethasone
Schatz et al12USA1978–89Prospective cohortn = 48611.1% received nebulised bronchodilators in clinic or ED8% used beclomethasone
Stenius-Aarniala et al13Finland1982–92Prospective and retrospective cohortn = 5046.5%3%ICS used by 34% of those who had an exacerbation and 62% of those who did not have an exacerbationLack of ICS use
Dombrowski et al14USA1992–5Historical cohortn = 5443%26% used beclomethasone
28% used triamcinolone acetonide
Kurinczuk et al1Australia1995–7Cross sectional surveyn = 7962% had an “asthma attack or wheezing” during pregnancyUnknown
Henderson et al15USA1960–5Prospective cohortn = 15742.2%Nil
Hartert et al16USA1985–93Historical cohortn = 24616%(during influenza season)UnknownInfluenza
Schatz et al17USA1994–9Prospective cohortn = 1739 overall5.1% overall
n = 873 mild2.3% mildNo ICS (mild)
n = 814 moderate n = 52 severe6.8% moderate 26.9% severeSome ICS use (moderate and severe)
Namazy et al18USA1996–2002Case seriesn = 4517.6% had an “acute attack”100% ICS use
Martel et al19Canada1990–2000Nested case-control studyn = 331513% ED or admission46% used ICS
Carroll et al20USA1995–2001Historical cohortn = 43156.3%11.1%16%
Bakhireva et al21North America1998–2003Prospective cohortn = 6542.5%67% used ICS without OCS
Otsuka et al22Japan1987–2003Historical cohortn = 5921.38% had “asthma attacks” during labour and delivery55.3%
Schatz and Liebman23USA2000–1Historical cohortn = 6330.2%3.8%16% before pregnancy, 10% during pregnancyNot using ICS before pregnancy
Murphy et al24Australia1997–2003Prospective cohortn = 1468.2%2.7%64% used ICSViral infection
Non-adherence to ICS