Effect of maternal asthma on the risk of specific congenital malformations: A population-based cohort study§

Authors

  • Lucie Blais,

    Corresponding author
    1. Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
    2. Hôpital du Sacré-Cæur de Montréal, Montréal, Québec, Canada
    3. Endowment Pharmaceutical Chair AstraZeneca in Respiratory Health
    • Université de Montréal, Faculté de pharmacie, C.P. 6128, succursale Centre-ville, Montréal (Québec), Canada H3C 3J7
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    • Tel.: (514) 343-6111 extension 1-3786, Fax: (514) 343-6120.

  • Fatima-Zohra Kettani,

    1. Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
    2. Hôpital du Sacré-Cæur de Montréal, Montréal, Québec, Canada
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  • Naoual Elftouh,

    1. Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
    2. Hôpital du Sacré-Cæur de Montréal, Montréal, Québec, Canada
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  • Amélie Forget

    1. Faculty of Pharmacy, Université de Montréal, Montréal, Québec, Canada
    2. Hôpital du Sacré-Cæur de Montréal, Montréal, Québec, Canada
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  • The results of this study were presented at the 49th Annual Meeting of the Teratology Society, June 27 to July 1, 2009, Puerto Rico, United States.

  • Funding This study was funded through a grant received from the Canadian Institutes for Health Research. The sponsor had no role in the design, analysis, interpretation and report of the results. The researchers were completely independent from the funders.

  • §

    Competing interests The authors have no competing interests to declare for this study.

Abstract

BACKGROUND

There is a lack of consensus in the literature about the effect of maternal asthma on the development of congenital malformations.

OBJECTIVE

To further examine the association between maternal asthma and the risk of congenital malformations.

METHODS

A cohort of 41,637 pregnancies from women with and without asthma who delivered between 1990 and 2002 was reconstructed by linking three Quebec (Canada) administrative databases. All cases of malformations were identified using either the medical services or the hospital databases. The main exposure was maternal asthma, defined by the presence of at least one asthma diagnosis and at least one prescription for an asthma medication at any time in the two years before or during pregnancy. Generalized Estimation Equation models were performed to estimate the adjusted odds ratio (OR) of congenital malformations as a function of maternal asthma.

RESULTS

The crude prevalences of any congenital malformation were 9.5% and 7.5% for women with and without asthma, respectively. Maternal asthma was significantly associated with an increased risk of any malformation (OR=1.30; 95% CI: 1.20-1.40) and three specific groups (at the 0.0028 level): nervous system (excluding spina bifida: OR=1.83; 1.37-2.83); respiratory system (OR=1.75; 1.21-2.53); and digestive system (OR=1.48; 1.19-1.85).

CONCLUSIONS

Maternal asthma increases the risk of specific groups of congenital malformations. The disease itself, through fetal oxygen impairment, is likely to play a role in this increased risk, but more research is needed to disentangle the relative effect of asthma and medications used to treat this disease. Birth Defects Research (Part A), 2010. © 2010 Wiley-Liss, Inc.

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