Asthma and pregnancy

Maternal asthma: pregnancy course and outcome

OBJECTIVE

To evaluate the association between maternal asthma and perinatal outcome.

STUDY DESIGN

In this retrospective population-based cohort study, all pregnancies between 1991 and 2014 in a tertiary medical center, were included. Multiple pregnancies and congenital malformations were excluded. Pregnancy course and outcomes were compared between women with and without asthma, and multivariable generalized estimating equations were used to control for confounders.

RESULTS

During the study period, 243,363 deliveries met the inclusion criteria, 1.35% of which (n = 3283) occurred in women diagnosed with asthma. Multiple perinatal complications were found to be associated with maternal asthma, including hypertensive disorders, preterm delivery, and cesarean delivery. However, no significant differences between the groups were noted in neonatal outcomes, including perinatal mortality rates and low Apgar scores. In the regression model, maternal asthma was noted as an independent risk factor for preterm delivery, hypertensive disorders of pregnancy, and cesarean delivery (aOR = 1.21, 95%CI 1.1-1.4, p = .007; aOR = 1.35, 95%CI 1.2-1.6, p < .001; and aOR = 1.27, 95%CI 1.2-1.4, p < .001, respectively) while controlling for multiple confounders.

CONCLUSIONS

Maternal asthma is associated with an increased risk for adverse pregnancy outcome. This association remains significant while controlling for variables considered to coexist with maternal asthma. Nevertheless, perinatal outcome is generally favorable.

Managing asthma in expectant mothers

Pregnancy does not appear to have a consistent effect on the frequency or severity of asthma. The most common cause of worsening asthma in pregnancy is likely to be noncompliance with medication. Emphasizing to the patient in advance that fetal well-being is dependent on maternal well-being may help prevent this.In general, well controlled asthma is not associated with a higher risk of adverse pregnancy outcomes. Essential to successful asthma management is patient education that helps to ensure effective medication use, avoidance of triggers, and prompt treatment. This education should include measurement of peak expiratory flow rate and a written asthma action plan. Most of the medications that are used to control asthma in the general population can be safely used in pregnant women. Inhaled beta-adrenoceptor agonists (beta-agonists), cromolyn sodium (sodium cromoglycate), and inhaled and systemic corticosteroids all appear to be very well tolerated by the fetus. Budesonide and beclomethasone should be considered as the preferred inhaled corticosteroids for the treatment of asthma in pregnancy. Use of the leukotriene receptor antagonists zafirlukast and montelukast in pregnancy is probably safe but should be limited to special circumstances, where they are viewed essential for asthma control. Zileuton should not be used in pregnancy.Acute asthma exacerbations in pregnant women should be treated in a similar manner to that in non-pregnant patients. Maternal blood glucose levels should be monitored periodically in pregnant women receiving systemic corticosteroids because of the deleterious effects of hyperglycemia upon embryos and fetuses. During pregnancy, maternal arterial oxygen saturations should be kept above 95% if possible for fetal well-being. Ambulatory oxygenation should be checked prior to discharge to ensure that women do not desaturate with their daily activities.Acute exacerbations of asthma during labor and delivery are rare. Dinoprost, ergometrine, and other ergot derivatives can cause severe bronchospasm, especially when used in combination with general anesthesia, and should be avoided in asthmatic patients. Pregnant women who have been treated with corticosteroids in the past year may require stress-dose corticosteroids during labor and delivery. Most asthma medications, including oral prednisone, are considered compatible with breast-feeding.

Use of inhaled and oral corticosteroids in pregnancy and the risk of malformations or miscarriage

Corticosteroids are potent anti-inflammatory and immunosuppressive drugs, which sometimes must be given to pregnant women. Corticosteroids have been suspected to be teratogenic for many years; however, there is conflicting evidence regarding the association. Based on a literature review of three databases, this MiniReview provides an overview of inhaled and oral corticosteroid use in pregnancy with specific emphasis on the association between use of corticosteroids during pregnancy and risk of miscarriage and congenital malformations in offspring. The use of corticosteroids among pregnant women ranged from 0.2% to 10% and increased nearly two times in recent years. Taken together, the evidence suggests that the use of corticosteroids in early pregnancy is not associated with an increased risk of congenital malformations overall or oral clefts in offspring; at the same time, published estimates are inconsistent. The use of inhaled corticosteroids was associated with a slightly increased risk of miscarriage, whereas the use of oral corticosteroids was not; however, confounding by indication could not be ruled out.

Risk of miscarriage among users of corticosteroid hormones: a population-based nested case-control study

BACKGROUND

The purpose of this nested case-control study in Denmark was to study the association between use of corticosteroids and risk of miscarriage.

METHODS

We identified prescriptions for corticosteroids before the miscarriage/index date. We estimated odds ratios (ORs) for miscarriage and for early (<13 weeks) and late (13-21 weeks) miscarriage adjusting for age, history of diabetes and epilepsy, and nonsteroidal anti-inflammatory drug use.

RESULTS

We identified 10,974 women with miscarriage and 109,740 controls. Prevalence of inhaled corticosteroid use within 60 days before the index date was 1.3% among the cases and 1.0% among the controls (OR = 1.20; 95% confidence interval [CI] 1.01-1.44). Prevalence of oral corticosteroid use within 60 days before the index date was 0.3% for both cases and controls (OR = 0.78; 95% CI 0.53-1.15). For inhaled and oral corticosteroids, the ORs of early miscarriage were 1.22 (95% CI 1.01-1.49) and 0.81 (95% CI 0.55-1.20), respectively.

CONCLUSION

Use of inhaled corticosteroids was associated with a slightly increased risk of early miscarriage, but explanations alternative to causal ones were possible.

Asthma management in pregnancy

BACKGROUND

Asthma is common during pregnancy, however research is limited regarding the extent and timing of changes in asthma management associated with pregnancy.

OBJECTIVE

To determine the prevalence of asthma during pregnancy and identify changes in treatment and asthma exacerbation rates associated with pregnancy, while controlling for seasonal influences.

METHODS

Pregnant women with asthma were identified from the UK General Practice Research Database between 2000 and 2008. For each woman asthma medication prescribed during the study period was identified; for each product combination the British Thoracic Society medication-defined asthma treatment step was identified. Asthma exacerbations were identified during pregnancy and in the corresponding 12 months prior. Analyses of changes in asthma treatment and exacerbation rates during pregnancy relative to the corresponding period 12 months prior, to control for seasonality, were stratified by trimester and asthma treatment intensity level.

RESULTS

The prevalence of treated asthma in pregnancies resulting in a delivery was 8.3%. From 14,141 pregnancies, in 12,828 women with asthma, 68.4% received prescriptions for a short-acting β2-agonist and 41.2% for inhaled corticosteroids; 76.5% were managed with asthma treatment Step 1 or 2. Poor persistence to inhaled corticosteroids, defined as a gap of up to 60 days between prescriptions, was common. In 45.0% of pregnancies, an increase in average treatment step was observed whereas in 25.6% the treatment step decreased. Treatment intensity remained the same in 29.5% of pregnancies. Exacerbations occurred in 4.8% of pregnancies compared to 5.9% in the same season the year before (p<0.001).

CONCLUSION

Exacerbation rates during pregnancy were slightly lower than in the year before. However, treatment patterns and exacerbation rates in this study suggest asthma control during pregnancy is variable, and women may require close monitoring especially in those with evidence of poor control before pregnancy.

Medication use for chronic health conditions by pregnant women attending an Australian maternity hospital

BACKGROUND

Most women use medications at some stage in their pregnancy. Medication nonadherence during pregnancy could be detrimental to both mother and fetus.

AIMS

To study the extent and nature of the use of prescribed medications during pregnancy and factors associated with medication nonadherence.

METHODS

All women≥18 years presenting for their 36th week antenatal visit at the pregnancy clinic of a maternity hospital were invited to complete an anonymous questionnaire that contained 61 items, including the Morisky scale. Factors associated with nonadherence were identified in univariate analysis; factors with P<0.1 were further analysed in a binary logistic regression model.

RESULTS

The participants (n=819) had a mean age of 30.8±5.3 years. Most participants were born in Australia, lived with a partner, had university education, were nulliparous, carried one fetus and were nonsmokers. Of these participants, 322 (39.3%) reported a chronic health condition during pregnancy, the most common being asthma (104; 12.7%). Two hundred and seventeen (26.5%) were using prescribed medications, which included anti-anaemics (68; 8.3%), medicines for chronic airway conditions (64; 7.8%), vitamins and minerals (59; 7.2%) and anti-diabetics (43; 5.2%). Nonadherence was reported by 107 (59.1%) participants, mainly because of forgetting (79; 43.6%). Factors associated with nonadherence were having asthma (OR 0.26 (95% CI 0.095-0.72), P=0.009) and using nonprescription dietary minerals (0.30 (0.10-0.87), P=0.027).

CONCLUSIONS

Adherence to prescribed medicines during pregnancy is alarmingly low. Health professionals should be more proactive in promoting adherence and assisting women avoid potential fetal harm because of nonadherence.

Inhaled Corticosteroids

Inhaled corticosteroids (ICS) are the most effective controllers of asthma. They suppress inflammation mainly by switching off multiple activated inflammatory genes through reversing histone acetylation via the recruitment of histone deacetylase 2 (HDAC2). Through suppression of airway inflammation ICS reduce airway hyperresponsiveness and control asthma symptoms. ICS are now first-line therapy for all patients with persistent asthma, controlling asthma symptoms and preventing exacerbations. Inhaled long-acting β₂-agonists added to ICS further improve asthma control and are commonly given as combination inhalers, which improve compliance and control asthma at lower doses of corticosteroids. By contrast, ICS provide much less clinical benefit in COPD and the inflammation is resistant to the action of corticosteroids. This appears to be due to a reduction in HDAC2 activity and expression as a result of oxidative stress. ICS are added to bronchodilators in patients with severe COPD to reduce exacerbations. ICS, which are absorbed from the lungs into the systemic circulation, have negligible systemic side effects at the doses most patients require, although the high doses used in COPD has some systemic side effects and increases the risk of developing pneumonia.

Effect of maternal asthma on birthweight and neonatal outcome in a British inner-city population

During pregnancy, asthma-related alterations in placental function and the maternal immune system, and reduced growth affecting female but not male fetuses have been reported in a study of selected Australian women. The objective of this study was to evaluate the effect of asthma management, declared during pregnancy, on birthweight and neonatal outcome at an inner-city hospital in England. Between June 2001 and December 2003, women at antenatal clinics were questioned about asthma (n = 10 983). Women with asthma and singleton uncomplicated pregnancies ending at term were selected (n = 718), with non-asthmatic controls (n = 718). Among asthmatic women using inhaled steroids and bronchodilators (n = 170), 43% of the newborn boys had birthweights <10th centile, compared with 27% of controls (P = 0.011; OR 2.51 [95% CI: 1.52, 4.14]). For girls, the proportions were 28% and 27%. In women using bronchodilators only (n = 178) or those declaring no treatment (n = 370), birthweights were not significantly reduced. Taking account of smoking, ethnicity, gestational age and parity, there was a mean birthweight reduction with inhaled steroids and bronchodilators of 118 g [95% CI 36.0, 199.0 g] compared with the control group. There was no interaction between the effect of asthma treatment and infant gender. Infants of asthmatic women in the three subgroups who required intensive care were more likely to exhibit transient tachypnoea of the newborn than infants of control women (P < 0.005). In our population-based sample, the risk of low birthweight among asthmatic women did not depend on infant gender, while neonatal respiratory morbidity remains a significant health issue in boys and girls.

Adverse maternal outcomes in women with asthma: differences by race

PURPOSE

To examine the relationship between race and adverse maternal outcomes in women with asthma.

STUDY DESIGN AND METHODS

This retrospective cohort study examined 11 adverse maternal outcomes across racial groups of 13,900 pregnant women with asthma (age 13 to > or = 40) who gave birth between 1998 and 1999. The data were abstracted from a national database, The National Inpatient Sample (NIS), available through Health Care and Utilization Project (HCUP) maintained and disseminated by the Agency for Healthcare Research and Quality (AHRQ). Maternal age and comorbidities were adjusted in multivariate analysis.

RESULTS

For women with asthma, African Americans were more likely than Whites to have preterm labor and infection of the amniotic cavity; Hispanic women had comparable outcomes with the exception that postdate pregnancy was less likely to be 42 weeks; and Asian/Pacific Islander women had a higher risk of having gestational diabetes and infection of the amniotic cavity.

CLINICAL IMPLICATIONS

As adverse maternal outcomes for women with asthma were higher in minorities, and as minorities have traditionally had more barriers to healthcare, the study results indicate that more effort needs to be made to educate nurses, consumers, and government officials about the potential adverse maternal outcomes of asthma during pregnancy. Public awareness may assist in overcoming the barriers to healthcare experienced by minorities.

Common problems and emergencies in the obstetric patient

Physicians not used to caring for pregnant patients may feel uncomfortable dealing with the many routine problems that can occur during a pregnancy. Other than true obstetric emergencies, which are usually cared for by obstetricians and family physicians, and the common problems of pregnancy can often be cared for by any primary care physician. Given the litigious nature of our society, especially in the realm of obstetrics, it does behoove the physician caring for pregnant women to be aware of the standards of care. When in doubt, it would be prudent to consult with a physician that routinely provides care to pregnant women.

Maternal atopy and changes in parity

BACKGROUND

Atopic women tend to have fewer children, although atopy may favour conception.

OBJECTIVE

To assess whether atopy is associated with the number of new births and whether changes in parity are associated with a change in atopy in a cohort of young women.

METHODS

Women had atopy (defined as the presence of serum-specific IgE against common aeroallergens) measured in the European Community Respiratory Health Study during the years 1991--92 (n=4580). About 9 years later, 2844 (62.1%) were recontacted and 2414 (52.7%) had atopy measured again.

RESULTS

Atopic women had fewer children at baseline than non-atopic women but the association disappeared at the end of the follow-up. Atopy tended to increase parity during the follow-up, but in a non-statistically significant way (relative risk=1.08; 0.86-1.35, after adjusting for number of children at baseline, age, length of follow-up, education or social class). Prevalence of atopy during the follow-up changed by the same magnitude whatever the birth cohort and the change in the number of children (P for interaction >0.7).

CONCLUSION

Atopic women did not have a significantly higher fertility rate but they may postpone having their first child compared with non-atopic women. We are unable to confirm the hypothesis that atopy in women may decrease with successive pregnancies.

Asthma in pregnancy

Asthma is a chronic inflammatory disease of the airway system that is characterized by bronchoconstriction and bronchial hyperresponsiveness that are triggered by a host of stimuli. Asthma is the most common respiratory disease in pregnancy and affects approximately 4% of pregnant women. This article reviews asthma as a public health concern, the normal physiology of pregnancy,the pathophysiology of asthma in pregnancy, the effects of asthma on pregnancy and pregnancy on asthma, objective lung function testing, goals for the pregnant woman who has asthma, and treatment of chronic and acute episodes of asthma.

Monitoring outcomes of pregnancy following drug exposure: a company-based pregnancy registry program

Women who discover they are pregnant after exposure to a drug and pregnant women who have a condition that requires continued treatment during pregnancy are told to balance the benefits and risks of the exposure to justify continuation of treatment, discontinuation of treatment or, possibly, pregnancy termination. However, there are limited data available to inform decision-making. The Merck Pregnancy Registry Program is a company-run pregnancy registry whose objective is to acquire and analyse information on drug exposures and pregnancy outcomes to better describe the safety profile of Merck products used during pregnancy. Information is collected from women and healthcare providers who call to report drug exposure during pregnancy. Prospective pregnancies are followed up to outcome and data are collected via questionnaires, telephone calls and a review of medical records. Reports are classified as prospective (information received prior to knowledge of pregnancy outcome) or retrospective (received after the outcome is known). Congenital anomaly reports are assessed for timing of exposure, maternal age and medical history, biological plausibility and concomitant medication exposures. Rates of pregnancy outcomes and birth defects in the prospective cohort are computed and confidence intervals are calculated to reflect the strength of the finding based on the sample size. Rates of pregnancy outcomes in the Pregnancy Registry are compared with the rates of pregnancy outcomes in the general US population and, if available, in subpopulations with the relevant disease states. The limitations of post-marketing surveillance are well known as voluntary reporting of individuals and healthcare professionals is known to be subject to various types of bias. Small sample size is another major limitation. However, the strength of the registry lies in its ability to gather pregnancy outcome reports early in the life of a product and to recognise and analyse unusual birth defects. Our data suggest that pregnancy registries can be used to review human exposure data in a systematic fashion so that useful information can be shared with women and their healthcare providers. The use of the pregnancy registry design has allowed for the collection and analysis of data on the effects of drug exposures on human pregnancies that have otherwise been difficult to obtain.

Respiratory disease in pregnancy

A variety of respiratory complications can be encountered in pregnancy. An understanding of the pathophysiology of pregnancy is important in the management of such complications. Despite the changes in immunity, the incidence of respiratory infections is not higher in pregnancy. Asthma is the most common preexisting medical disorder encountered in pregnancy, and its prevalence in women of childbearing age is increasing. There is a slight increase in the risk to the pregnancy, but suboptimal therapy is the most common reason for poor control. X-rays should be obtained whenever clinically indicated, and most drugs used in the management of asthma have a long track record of safety. For women with poor control in pregnancy, there should be good liaison between the respiratory physician and the obstetrician. Tuberculosis is increasingly important and may complicate human immunodeficiency virus infection. First-line antituberculous drugs can safely be administered in pregnancy and lactation.

General strategy for the management of bronchial asthma in pregnancy

Epidemiological studies showed that bronchial asthma is one of the most common diseases which can complicate pregnancy (1-7%). In about 0.05-2% of the cases, asthma occurs as a life-threatening event. In the common medical practice a waiting strategy or, even, the complete refusal for drug therapies are frequently observed. This is justified by the fear of the possible adverse effects of drugs on developing fetus. On the contrary, several studies have demonstrated that severe and uncontrolled asthma may produce serious maternal and fetal complications, such as gestational hypertension and eclampsia, fetal hypoxemia and an increased risk of perinatal death. Therefore, all pregnant women suffering from bronchial asthma should be considered as potentially at high risk of complications and adequately treated. Since asthma is a chronic disease with acute exacerbations, a continuous treatment is mandatory to control symptoms, to prevent acute episodes and to reduce the degree of airway inflammation. The global strategy for asthma management in pregnancy includes five main topics: (1) objective evaluation of maternal/ fetal clinical conditions; (2) avoidance/control of triggering factors; (3) pharmacological treatment; (4) educational support; (5) psychological support. As far as drug therapy is concerned, the International Guidelines and Recommendations suggest that the general strategy does not differ significantly from management outside pregnancy. We herein review and discuss the available data and the criteria for the management of asthma in pregnant patients.

Maternal atopy and parity

BACKGROUND

Family size and high birth order were related to the prevalence of hayfever and positive skin prick test. However, this association may be explained by maternal atopy. We examined the relationship between maternal atopy and the number of offspring in three European cohorts of pregnant women.

METHODS

The mothers and their children (n = 1487) were recruited for the Asthma Multi-centre Infants Cohort Study (AMICS). The three concurrent cohorts (Ashford, Kent (UK); Menorca island (Spain) and Barcelona city (Spain) followed the same research protocol. Maternal and paternal atopy was identified by skin prick tests at different times at the three centres.

RESULTS

Maternal atopy was inversely related to the number of offspring, an association which occurred in each of the three cohorts and remained when atopy was defined separately for individual allergens (a positive response to testing with either Der p 1 or grass pollen) and which was not confounded by maternal age, smoking nor social class (the adjusted odds ratios were 0.71, 0.79 and 0.26 for increasing number of offspring, P = 0.002). Neither maternal asthma (P = 0.43) nor paternal atopy (P = 0.58) were associated with the number of offspring. Maternal atopy was not related to reproductive outcomes.

CONCLUSIONS

The association between maternal atopy and parity challenges the role of family size on child atopy, which should be studied in other populations.

A population-based prescription study of asthma drugs during pregnancy: changing the intensity of asthma therapy and perinatal outcomes

BACKGROUND

Among the goals of gestational asthma, therapy is optimisation of pulmonary function. According to the US Food and Drug Administration, no asthma drugs can be considered 'safe' during pregnancy. Fear of adverse fetal effects may thus lead to restrictive use of asthma drugs during pregnancy, and no population-based studies concerning gestational asthma therapy exist.

OBJECTIVES

To examine whether asthma drugs or changing intensity of asthma therapy during pregnancy was associated with deviations from expected values of gestational age, birth weight, length at birth, or malformations.

METHODS

The Birth Registry was used to identify all 15,756 primiparous women who gave birth in the County of North Jutland between 1991 and 1996. According to the North Jutland Prescription Database, 303 of these women received prescriptions for asthma drugs during pregnancy. Women who did not purchase any prescription drugs during pregnancy constituted the reference group.

CONCLUSION

Women who received prescriptions for asthma drugs during pregnancy gave birth to infants with birth weight and length at birth within the expected limits. Reducing intensity of asthma treatment during pregnancy was associated with lower birth weight and length at birth. This may indicate that pregnant women chose to discontinue therapy although their disease severity justifies continuation of treatment. However, analyses did not take into account important clinical variables, and results could also be due to confounding factors or chance.

Maternal asthma and pregnancy outcomes: a retrospective cohort study

OBJECTIVE

We examined the relationship between asthma during pregnancy and selected infant and maternal outcomes.

STUDY DESIGN

A retrospective cohort study was conducted on mother-infant dyads identified from a linked infant and maternal hospital discharge database in the Canadian province of Quebec between fiscal years 1991-1992 and 1995-1996. Mothers with asthma (n = 2193) were compared with a randomly selected control sample (n = 8772) from the remaining population of mothers.

RESULTS

After important confounding variables were accounted for, maternal asthma was significantly associated with several adverse infant outcomes, including preterm birth and birth of infants who are very small for gestational age, and adverse maternal outcomes, such as idiopathic preterm labor, early idiopathic preterm labor, preeclampsia, transient hypertension of pregnancy, pregnancy-associated hypertension, chorioamnionitis, and cesarean delivery.

CONCLUSION

Our results demonstrated that pregnant women with asthma are at substantially increased risk for several adverse infant and maternal outcomes and suggest the need for extra attention to mothers with asthma and their infants.

Risk of congenital malformations associated with treatment of asthma during early pregnancy

Studies assessing the risk of congenital malformations associated with the treatment of asthma during the first trimester of pregnancy are few, have limited power and support continuation of treatment.