Original Articles: Asthma, Lower Airway Diseases
Asthma control during pregnancy and the risk of preterm delivery or impaired fetal growth

https://doi.org/10.1016/S1081-1206(10)60201-3Get rights and content

Background

Concerns regarding potential harmful effect of medications on fetuses often result in inadequate treatment of asthma in pregnancy, whereas risks posed by poorly controlled maternal asthma are often underestimated.

Objective

To evaluate the effect of maternal asthma on preterm delivery and fetal growth.

Methods

Study participants were individuals enrolled in the Organization of Teratology Information Specialists Asthma Medications in Pregnancy Study between February 1, 1998, and December 31, 2003. Pregnant women with physician-diagnosed asthma (n = 719) evaluated their asthma control repeatedly during pregnancy based on symptom frequency and interference with daily activities and sleep and reported hospitalizations and unscheduled clinic visits for asthma exacerbations. The incidence of preterm delivery, the incidence of intrauterine growth restriction, and mean birth weight were evaluated relative to asthma symptom control and exacerbation measures.

Results

The incidence of preterm delivery was significantly higher among patients with inadequate asthma symptom control during the first part of pregnancy (11.4%) compared with patients with adequate asthma control (6.3%; P = .02). Similarly, patients who were hospitalized for asthma during pregnancy had a higher incidence of preterm delivery (16.4%) compared with asthmatic women without a history of hospitalization (7.6%; P = .02). The effect seemed independent from use of systemic corticosteroids and other covariates. Neither the incidence of intrauterine growth restriction nor mean birth weight varied by any measures of asthma symptom control or exacerbations.

Conclusions

This study demonstrates a substantial risk for preterm delivery posed by poorly controlled maternal asthma and provides additional evidence regarding the importance of adequate treatment of asthma in pregnancy to maintain optimal asthma control.

Section snippets

INTRODUCTION

Asthma is a chronic disorder that affects up to 8% of pregnant women in the United States. 1 Previous data suggest that women with asthma, especially severe asthma, have a higher rate of adverse perinatal outcomes, including preterm delivery and impaired fetal growth. 2 Intrauterine growth restriction (IUGR) and preterm delivery are common pregnancy complications that are associated with increased mortality and morbidity in the neonatal period and might have long-term consequences, such as

Study Population

Study participants were individuals enrolled in the multicenter, prospective study of Asthma Medication Use in Pregnancy conducted by the Organization of Teratology Information Specialists (OTIS) between February 1, 1998, and December 31, 2003. The methods of the study have been described elsewhere. 8, 13, 14 Briefly, 819 pregnant women with physician-diagnosed asthma were recruited through the OTIS counseling network in North America and were followed up through a central coordinating center

RESULTS

Among 719 women with asthma, 396 (56.3%) reported adequate control of asthma at their first maternal interview, whereas 308 (43.7%) reported fair to poor control of asthma, and 15 women had missing values for this variable (Table 1). At subsequent maternal interviews, a slightly smaller proportion of patients reported poor to fair control of their asthma (35.3% and 30.4%, respectively). During pregnancy 8.5% of patients were hospitalized for asthma and 21.3% had unscheduled asthma clinic visits.

DISCUSSION

In this study, poor maternal asthma symptom control early in pregnancy and a history of hospitalizations for asthma anytime during pregnancy were each associated with a doubling of the risk of preterm delivery independent of other risk factors. Increased risk of preterm delivery might be attributed to hypoxia secondary to severe and uncontrolled asthma or to an effect of asthma therapy during pregnancy: 2 factors that are often difficult to disentangle. Systemic corticosteroids are a class of

REFERENCES (33)

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    Citation Excerpt :

    Several studies have suggested an increased risk of adverse outcomes among pregnancies of women with asthma, including prematurity, intrauterine growth restriction, emergency cesarean delivery, and maternal mortality.1,3,5-14 However, other investigations have yielded contrasting results.8,9,11,15-17 Possible sources of heterogeneity in these findings include differences in the level of asthma severity and control across study populations and distinct focus on asthma diagnosis overall, severe asthma, or asthma exacerbations.

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Disclosures: Dr Jones has consulting arrangements with Merck. Dr Chambers has consulting arrangements with Cephalom Pharmaceutical. Drs Jones and Chambers have received grant support from Sanofi-Aventis, Sanofi-Pasteur, Abbott Laboratories, Amgen, Apotex, Barr Laboratories, Kali Laboratories, Sandoz Pharmaceutical, Teva Pharmaceutical, and Bristol Myers Squibb. Dr Schatz has received grant support from GlaxoSmithKline and Sanofi-Aventis and has received honoraria from GlaxoSmithKlein, Genentech, and Merck. Dr Bakhireva has no conflict of interest.

Funding Sources: This research was supported by a grant from Aventis Pharmaceutical.

The following members of the OTIS Collaborative Research Group contributed to this study: Arizona Teratogen Information Program, University of Arizona, Tucson: D. Quinn, D. Vogt; California Pregnancy Risk Information, University of California, San Diego: K. Kao; Connecticut Pregnancy Exposure Information Service, University of Connecticut Health Center, Farmington: S. Lavigne, J. Brochu; Nebraska Teratogen Project, University of Nebraska Medical Center, Omaha: Dr B. Buehler, E. Conover; Illinois Teratogen Information Service, Chicago: K. Ormond, C. Chou; Michigan Teratogen Information Service, Children's Hospital of Michigan, Detroit: Dr Y. Johnson, S. Swerc; Missouri Teratogen Information Service, University of Missouri Hospital and Clinics, Columbia: Dr S. Braddock, P. Slusher; Pregnancy Risk Network, University of Buffalo: Dr L. Robinson, S. Gangell; Motherisk Program, Hospital for Sick Children, Toronto, Ontario: Dr G. Koren, M. Morreti; Texas Teratogen Information Service, University of North Texas, Denton: L. Wolfe; Pregnancy RiskLine Project, Utah Department of Health, Salt Lake City: Dr J. Carey; J. Robertson; CARE Northwest, University of Washington, Seattle: Dr J. Polifka, Dr E. Rudy.

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