Risk of perinatal mortality associated with asthma during pregnancy: a 2-stage sampling cohort study

Chronic Management of Asthma During Pregnancy

Asthma is one of the most common potentially serious medical problems to complicate pregnancy. Optimal management of asthma during pregnancy is thus important for both mother and baby. Treating asthmatic women requires understanding the effects of pregnancy on the course of asthma, and, conversely, the effects of asthma on pregnancy outcomes. Successful management also requires an understanding the barriers to asthma control in this population of patients. Evidence has shown that it is essential that the allergist-immunologist, obstetrician, and patient work as a team during pregnancy to achieve optimal maternal and neonatal outcomes.

Contemporary management and treatment strategies for asthma during pregnancy

Introduction: Asthma is one of the most common conditions that afflict pregnant women. Because uncontrolled asthma in pregnancy affects both maternal and offspring outcomes, careful attention to maintaining control of asthma symptoms throughout pregnancy is of critical importance.Areas Covered: Using a search of PUBMED/MEDLINE for 'asthma and pregnancy,' this article will review the current literature regarding epidemiology and course of asthma in pregnancy, the effects of uncontrolled asthma on both the mother and offspring, and provide an overview of the management, both non-pharmacologic and pharmacologic, of asthma in pregnancy.Expert Opinion: There is a lack of adequate safety information for most medications taken during pregnancy. Future research might allow better methods to predict which women will experience worsening during pregnancy. For now, surveillance systems like pregnancy registries or observational cohort studies can provide safety information for medications used during pregnancy.

Exacerbations of asthma during pregnancy: Impact on pregnancy complications and outcome

Asthma is common among pregnant women, and the incidence of asthma exacerbations during pregnancy is high. This literature review provides an overview of the impact of exacerbations of asthma during pregnancy on pregnancy-related complications. The majority of published retrospective studies reveal that asthma exacerbations during pregnancy increase the risk of pre-eclampsia, gestational diabetes, placental abruption and placenta praevia. Furthermore, these women also have higher risk for breech presentation, haemorrhage, pulmonary embolism, caesarean delivery, maternal admission to the intensive care unit and longer postpartum hospital stay. Asthma has been associated with increased risk of intrauterine growth retardation, small-for-gestational age, low birth weight, infant hypoglycaemia and preterm birth, but more recent prospective studies have not revealed significant associations with regard to these outcomes. In conclusion, asthma exacerbations during pregnancy are associated with complications of pregnancy, labour and delivery. Prevention of exacerbations is essential to reduce the risk of complications and poor outcome.

A systematic review of validated methods to capture stillbirth and spontaneous abortion using administrative or claims data

PURPOSE

To identify and assess diagnosis, procedure and pharmacy dispensing codes used to identify stillbirths and spontaneous abortion in administrative and claims databases from the United States or Canada.

METHODS

We searched the MEDLINE database from 1991 to September 2012 using controlled vocabulary and key terms related to stillbirth or spontaneous abortion. We also searched the reference lists of included studies. Two investigators independently assessed the full text of studies against pre-determined inclusion criteria. Two reviewers independently extracted data regarding participant and algorithm characteristics and assessed each study's methodological rigor using a pre-defined approach.

RESULTS

Ten publications addressing stillbirth and four addressing spontaneous abortion met our inclusion criteria. The International Classification of Diseases, Ninth Revision (ICD-9) codes most commonly used in algorithms for stillbirth were those for intrauterine death (656.4) and stillborn outcomes of delivery (V27.1, V27.3-V27.4, and V27.6-V27.7). Papers identifying spontaneous abortion used codes for missed abortion and spontaneous abortion: 632, 634.x, as well as V27.0-V27.7. Only two studies identifying stillbirth reported validation of algorithms. The overall positive predictive value of the algorithms was high (99%-100%), and one study reported an algorithm with 86% sensitivity. However, the predictive value of individual codes was not assessed and study populations were limited to specific geographic areas.

CONCLUSIONS

Additional validation studies with a nationally representative sample are needed to confirm the optimal algorithm to identify stillbirths or spontaneous abortion in administrative and claims databases.'

Relative perinatal safety of salmeterol vs formoterol and fluticasone vs budesonide use during pregnancy

BACKGROUND

Recent asthma guidelines endorse the safety of long-acting β2-agonists (LABAs) and of mild and moderate doses of inhaled corticosteroids (ICSs) when required to control asthma during pregnancy, yet do not state a preferred medication within each class.

OBJECTIVE

To estimate the relative perinatal safety with the use of salmeterol and formoterol (LABAs) and that of fluticasone and budesonide (ICSs) during pregnancy.

METHODS

A subcohort of pregnancies from asthmatic women was selected from health care administrative databases of Quebec, Canada. Low birth weight (LBW) was defined as weight less than 2,500 g, preterm birth (PB) as delivery before 37 weeks of gestation, and small for gestational age (SGA) as a birth weight below the 10th percentile. The effect of treatment with salmeterol vs formoterol and fluticasone vs budesonide on the outcomes was determined with generalized estimating equation models.

RESULTS

The LABA and ICS subcohorts were composed of 547 (385 salmeterol and 162 formoterol users) and 3,798 (3,190 fluticasone and 608 budesonide users) pregnancies, respectively. No statistically significant differences were observed for LBW (odds ratio [OR], 0.91; 95% confidence interval [CI], 0.44-1.88), PB (OR, 1.11; 95% CI, 0.56-2.23), and SGA (OR, 1.16; 95% CI, 0.67-2.02) newborns between women exposed to salmeterol vs formoterol or between women exposed to fluticasone vs budesonide (LBW: OR, 1.08; 95% CI, 0.76-1.52; PB: OR, 1.07; 95% CI, 0.78-1.49; and SGA, OR: 1.10; 95% CI, 0.85-1.44).

CONCLUSION

This study does not provide evidence of greater perinatal safety for one LABA or one ICS over the other.

Associations of maternal asthma severity and control with pregnancy complications

OBJECTIVES

To assess the associations of maternal asthma severity and control with pregnancy-induced hypertension (PIH), gestational diabetes and cesarean delivery.

METHODS

A cohort of 41 660 pregnancies from women with and without asthma who delivered between 1990 and 2002 was constructed by linking Québec's administrative databases. Maternal asthma was defined by at least one asthma diagnosis and one dispensed prescription for an asthma medication in the 2 years before or during pregnancy. Asthma severity and control were assessed using validated indexes during the entire pregnancy to study cesarean delivery and 1-year prior to week 20 of gestation to study PIH and gestational diabetes. Generalized Estimation Equation models were used to obtain odds ratios (OR) for PIH, gestational diabetes and cesarean in association with maternal asthma severity and control.

RESULTS

Almost one-third of the women had uncontrolled asthma and up to 5% had severe asthma. Severe asthma increased the risk of cesarean delivery (OR = 1.35; 95% CI: 1.11-1.63) compared with mild asthma, but no association was found between asthma severity and the other outcomes. The level of asthma control was not associated with any of the outcomes, except for a near-significant increased risk of PIH among uncontrolled women (OR = 1.18; 95% CI: 0.97-1.42).

CONCLUSIONS

The risk of gestational diabetes was not associated with asthma severity or control, and the risk of PIH was not associated with asthma severity. However, further studies are needed to clarify the association between asthma control and PIH. The increased risk of cesarean among women with severe asthma may be explained by the physician's and patient's concerns over the safety of normal delivery.

Impact of obesity on perinatal outcomes among asthmatic women

BACKGROUND

Only one study has investigated the combined effect of maternal asthma and obesity on perinatal outcomes; however, it did not consider small-for-gestational age and large-for-gestational age infants.

OBJECTIVES

To examine the impact of obesity on perinatal outcomes among asthmatic women.

METHODS

A cohort of 1386 pregnancies from asthmatic women was reconstructed using three of Quebec's administrative databases and a questionnaire. Women were categorized using their prepregnancy body mass index. Underweight, overweight and obese women were compared with normal weight women. The primary outcome was the birth of a small-for-gestational-age infant, defined as a birth weight below the 10th percentile for gestational age and sex. Secondary outcomes were large-for-gestational-age infants (birth weight >90th percentile for gestational age) and preterm birth (<37 weeks' gestation). Logistic regression models were used to obtain the ORs of having small-for-gestational-age infants, large-for-gestational-age infants and preterm birth as a function of body mass index.

RESULTS

The proportions of underweight, normal weight, overweight and obese women were 10.8%, 53.3%, 19.7% and 16.2%, respectively. Obese asthmatic women were not found to be significantly more at risk for giving birth to small-for-gestational-age infants (OR 0.6 [95% CI 0.4 to 1.1]), large-for-gestational-age infants (OR 1.2 [95% CI 0.7 to 2.2]) or having a preterm delivery (OR 0.7 [95% CI 0.4 to 1.3]) than normal-weight asthmatic women.

CONCLUSIONS

No significant negative interaction between maternal asthma and obesity on adverse perinatal outcomes was observed.

The poorly explored impact of uncontrolled asthma

The goal of asthma management is to achieve disease control; however, despite the availability of effective and safe medications, for many patients asthma remains uncontrolled. One reason for this is the fear of long-term side effects from the regular use of inhaled corticosteroids (ICSs). Adverse effects of poorly controlled asthma (for example, obesity, pneumonia, and risks to the fetus) can be perceived as side effects of ICSs. Poorly controlled asthma adversely affects children's cardiovascular fitness, while children with well-controlled asthma perform at the same level as their peers. Children with uncontrolled asthma also have a higher frequency of obesity than children with controlled asthma. Stress can affect asthma control, and children with poorly controlled asthma are more likely to have learning disabilities compared with those with good control. In adults, focused attention and concentration are negatively affected in patients with untreated asthma, and patients with asthma are at greater risk for depression. Also, poorly controlled asthma increases the risks of severe asthma exacerbations following upper respiratory and pneumococcal pulmonary infections. ICSs used to improve asthma control have been demonstrated to improve all of these outcomes. Lastly, the risks of uncontrolled asthma during pregnancy are substantially greater than the risks of recommended asthma medications. Treatments to maintain asthma control are the best approach to optimize maternal and fetal health in the pregnancies of women with asthma. The maintenance of asthma control has significant advantages to patients and greatly outweighs the potential risks of treatment side effects.

Validity of congenital malformation diagnostic codes recorded in Québec's administrative databases

PURPOSE

To assess the validity of the diagnostic codes of congenital malformations (CMs) recorded in two of Québec's administrative databases.

METHODS

A cohort of pregnancies and infants born to asthmatic and non-asthmatic women in 1990-2002 was reconstructed using Québec's administrative databases. From this cohort, we selected 269 infants with a CM and 144 without CM born to asthmatic women, together with 284 and 138 infants, respectively, born to non-asthmatic women. The diagnoses of CMs recorded in the databases were compared with the diagnoses written by the physicians in the infants' medical charts. The positive predictive values (PPV) and negative predictive values (NPV) for all, major, and several specific CMs were estimated.

RESULTS

The PPVs for all CMs and major CMs were 82.2% (95% confidence interval (CI): 78.5%-85.9%) and 78.1% (74.1%-82.1%), respectively, in the asthmatic group and were 79.2% (75.4%-83.1%) and 69.0% (64.6%-73.4%), respectively, in the non-asthmatic group. PPVs >80% were found for several specific CMs, including cardiac, cleft, and limb CMs in both groups. The NPV for any CM was 88.2% (95% CI: 85.1%-91.3%) in the asthmatic group and 94.2% (92.2%-96.2%) in the non-asthmatic group.

CONCLUSIONS

Québec's administrative databases are valid tools for epidemiological research of CMs. The results were similar between infants born to women with and without asthma.

Relationship between changes in inhaled corticosteroid use and markers of uncontrolled asthma during pregnancy

STUDY OBJECTIVE

To describe changes in inhaled corticosteroid use during pregnancy and markers of uncontrolled asthma, and to evaluate the association between them.

DESIGN

Population-based, cross-sectional study.

DATA SOURCE

Three administrative claims databases in Québec, Canada.

PATIENTS

A cohort of 4434 asthmatic women (4920 pregnancies) who delivered their infants between 1990 and 2002 and who used inhaled corticosteroids before their pregnancy.

MEASUREMENTS AND MAIN RESULTS

The average daily doses of inhaled corticosteroids during pregnancy and during the 9 months before conception were compared; the change in use was categorized as discontinuation (reduction of ≥75%), reduction (26-75% reduction), no change (±25% change), or increase (increase of ≥25%). The markers of uncontrolled asthma included at least one asthma exacerbation and the use of three or more doses/week of a short-acting β(2) -agonist during pregnancy. Generalized estimating equation models were used for statistical analyses. In nearly 50% of the pregnancies (2388 [48.5%] of 4920), the women either stopped or reduced their doses of corticosteroid during pregnancy, and these doses were already quite low before pregnancy. The proportion of women who had an asthma exacerbation during pregnancy was 8.2% among women who discontinued corticosteroids and greater than 20% in all of the other groups. All of the groups used frequent doses of short-acting β(2) -agonists. Discontinuing inhaled corticosteroid use during pregnancy was associated with a lower risk of exacerbations (odds ratio [OR] 0.42, 95% confidence interval [CI] 0.33-0.54), whereas increasing inhaled corticosteroid use was associated with a higher risk (OR 1.42, 95% CI 1.17-1.72), compared with no change in use.

CONCLUSION

Because of residual confounding by asthma severity, our study was not able to show that women who stopped inhaled corticosteroids during pregnancy were at increased risk of having an asthma exacerbation. However, women who stopped corticosteroids tended to have a milder form of asthma, which is reassuring and suggests that women can recognize, to a certain extent, the need to continue taking their controller agents if necessary.