Asthma and pregnancy: a review of two decades

Associations of Diabetes, Mental Health, and Asthma with Hypertensive Disorders of Pregnancy: A Population-based Case-Control Study in Alberta, Canada

OBJECTIVE

To explore direct and indirect associations of diabetes, mental health, and asthma diagnosed before or during pregnancy with gestational hypertension (GH) or preeclampsia (PE).

STUDY DESIGN

This population-based case-control study conducted in Alberta, Canada, analyzed perinatal registry data from primiparous pregnant women aged 16 years and above, with no prior hypertension history, during the period 2010 to 2013. Cases of GH and PE were matched on gestational age with a random sample of controls at a 1:3 ratio.

MAIN OUTCOME MEASURES

We examined the presence of type 2 diabetes mellitus (T2DM) or gestational diabetes, depression, anxiety, and asthma diagnoses within five years before and during pregnancy. To estimate direct and indirect associations between these diagnoses and GH and PE, we used multivariable logistic and mediation models, adjusting for covariates.

RESULTS

The analysis included 18,381 women (3,443 GH cases, 1,152 PE cases, and 13,786 controls). We found a direct association between anxiety during pregnancy and GH (adjusted Odds Ratio [aOR] 2.18, 95 % confidence interval (CI) 1.43-3.31). Depression before pregnancy increased the odds of anxiety during pregnancy (aOR 4.78, 95 % CI 2.89-7.92) resulting in an indirect effect on GH (aOR 3.63, 95 % CI 1.67--7.87). For PE, we observed direct associations with pre-pregnancy T2DM (aOR 1.58, 95 % CI 1.12-2.24), gestational diabetes (aOR 1.28, 95 % CI 1.04-1.56), and asthma during pregnancy (aOR 2.23, 95 % CI 1.41-3.51).

CONCLUSION

These findings highlight the interplay of mental health factors in influencing GH and underscore the clinical importance of diabetes and asthma in the pathogenesis of PE.

Quality of life and asthma control in pregnant women with asthma

Background

Asthma is the most commonly occurring respiratory illness during pregnancy. Associations with complications of pregnancy and adverse perinatal outcome have been established. However, little is known about quality of life (QoL) in pregnant women with asthma and how it relates to asthma control particularly for Iran.

Objective

To determine the relationship between asthma related QoL and asthma control and severity.

Methods

We conducted a prospective study in pregnant women with asthma. We used the Asthma Control Questionnaire and the Asthma Quality of Life Questionnaire (AQLQ) and the guidelines of the Global Initiative for Asthma for assessment of asthma severity.

Results

Among 1603 pregnant women, 34 were diagnosed with asthma. Of these 13 had intermittent, 10 mild, 8 moderate and 3 severe persistent asthma. There was a significant decrease of QoL with poorer asthma control (p = 0.014). This decline could be due to limitations of activity in those with poorer asthma control, which is underlined by the significant decline of QoL with increasing asthma severity (p = 0.024).

Conclusion

Although the majority of pregnant women with asthma had a favorable score in AQLQ, reduced QoL was related to increased asthma severity and poor asthma control. This underlines the importance of controlling asthma during pregnancy not only for the prevention of adverse pregnancy outcomes but also for the preservation of QoL.

A Multi-Objective Approach for Drug Repurposing in Preeclampsia

Preeclampsia is a hypertensive disorder that occurs during pregnancy. It is a complex disease with unknown pathogenesis and the leading cause of fetal and maternal mortality during pregnancy. Using all drugs currently under clinical trial for preeclampsia, we extracted all their possible targets from the DrugBank and ChEMBL databases and labeled them as "targets". The proteins labeled as "off-targets" were extracted in the same way but while taking all antihypertensive drugs which are inhibitors of ACE and/or angiotensin receptor antagonist as query molecules. Classification models were obtained for each of the 55 total proteins (45 targets and 10 off-targets) using the TPOT pipeline optimization tool. The average accuracy of the models in predicting the external dataset for targets and off-targets was 0.830 and 0.850, respectively. The combinations of models maximizing their virtual screening performance were explored by combining the desirability function and genetic algorithms. The virtual screening performance metrics for the best model were: the Boltzmann-Enhanced Discrimination of ROC (BEDROC)α=160.9 = 0.258, the Enrichment Factor (EF)1% = 31.55 and the Area Under the Accumulation Curve (AUAC) = 0.831. The most relevant targets for preeclampsia were: AR, VDR, SLC6A2, NOS3 and CHRM4, while ABCG2, ERBB2, CES1 and REN led to the most relevant off-targets. A virtual screening of the DrugBank database identified estradiol, estriol, vitamins E and D, lynestrenol, mifrepristone, simvastatin, ambroxol, and some antibiotics and antiparasitics as drugs with potential application in the treatment of preeclampsia.

Prevalence of asthma and other allergic diseases in pregnant women

Asthma and allergic disorders can affect the outcome of pregnancy. Asthma and allergies are common comorbidities during pregnancy and exacerbations are the major clinical problem. Results are not consistent between studies .Therefore, the aim of this study was to determine the frequency of asthma and allergic disease during pregnancy. This prospective cohort study was carried out at the antenatal clinic of Mobini Hospital in Iran. Overall, 1,603 women were enrolled prior to the 24th week of pregnancy. All participants were interviewed for allergy disease, allergic trigger factors and severity of asthma. Also, asthma control was categorized as per GINA guidelines. The diagnosis of asthma was based on symptoms, pulmonologist diagnosis, and spirometry assessment. The results were analyzed using SPSS version 20 and T-tests and Chi-square test. The prevalence of asthma during pregnancy was 2.1% among the participants. The most common allergens in asthmatic group were pollen, stress, and climate. There was a significant relationship between age, education and place of living in asthmatic and non-asthmatic group, p = 0.003, p=0.05, p=0.008, respectively. There was a significant relationship between asthma symptoms among the two groups (p=0.001). In addition, a significant relationship was found between asthma and other allergic diseases including eczema, allergy, rhinitis, and wheeze in asthmatic women, with a significant relationship between wheeze and coughing and allergy. Exposure of the pregnant women to high levels of allergens, like pollen, and allergic diseases resulted in an increased risk of pregnancy outcomes. Careful management of these diseases should prevent most of the serious complications

Asthma prevalence among women aged 18 to 44 in the United States: National health and nutrition examination survey 2001-2016

Objective: To provide updated prevalence estimates of asthma and asthma medication use for women of childbearing age in the United States.Methods: Using data from 11,383 women aged 18-44, including a subset of 1,245 pregnant women, enrolled in the National Health and Nutrition Examination Survey (2001-2016), we assessed the age-adjusted prevalence of self-reported diagnosed asthma. For women aged 18-44, we stratified by year, demographics, and other characteristics. Furthermore, we assessed asthma medication use among women aged 18-44 with asthma.Results: After age-adjustment, 9.9% (95% confidence interval (CI) 9.2%, 10.7%) of women aged 18-44 and 10.9% (95% CI 7.2%, 14.6%) of pregnant women reported having asthma. Asthma prevalence was highest in 2015-2016 (12.0% 95% CI 9.8%, 14.3%) and lowest in 2003-2004 (8.6% 95% CI 6.4%, 10.8%). Women aged 18-44 with Medicaid or State Children's Health Insurance Program insurance coverage (16.8% 95% CI 14.5%, 19.2%), obesity (14.4% 95% CI 12.9%, 15.8%), diabetes (18.7% 95% CI 12.1%, 25.2%), hypertension (16.6% 95% CI 14.2%, 19.0%), and current smokers (12.8% 95% CI 11.4%, 14.2%) had the highest asthma prevalence. Of women with asthma, 38.3% (95% CI 34.5%, 42.1%) reported using asthma medications in the past 30 days.Conclusions: Among women of childbearing ages, asthma burden varies across demographic and clinical characteristics and has increased in recent years.

Fetal brain sparing in a mouse model of chronic maternal hypoxia

Hypoxic stress is a common occurrence during human pregnancy, yet little is known about its effects on the fetal brain. This study examined the fetal hemodynamic responses to chronic hypoxia in an experimental mouse model of chronic maternal hypoxia (11% O₂ from E14.5 to E17.5). Using high-frequency Doppler ultrasound, we found fetal cerebral and ductus venosus blood flow were both elevated by 69% and pulmonary blood flow was decreased by 62% in the fetuses exposed to chronic hypoxia compared to controls. This demonstrates that brain sparing persists during chronic fetal hypoxia and is mediated by "streaming," where highly oxygenated blood preferentially flows through the ductus venosus towards the cerebral circulation, bypassing the liver and the lungs. Consistent with these changes in blood flow, the fetal brain volume measured by MRI is preserved, while the liver and lung volumes decreased compared to controls. However, hypoxia exposed fetuses were rendered vulnerable to an acute hypoxic challenge (8% O₂ for 3 min), demonstrating global blood flow decreases consistent with imminent fetal demise rather than elevated cerebral blood flow. Despite this vulnerability, there were no differences in adult brain morphology in the mice exposed to chronic maternal hypoxia compared to controls.

Using a Mixture-of-Bivariate-Regressions Model to Explore Heterogeneity of Effects of the Use of Inhaled Corticosteroids on Gestational Age and Birth Weight Among Pregnant Women With Asthma

Asthma is a heterogeneous disease, and responses to asthma medications vary noticeably among patients. A substantively oriented objective of this study was to explore the potentially heterogeneous effects of exposure to maternal inhaled corticosteroids (ICS) on gestational age (GA) at delivery and birth weight (BW) using a cohort of 6,197 pregnancies among women with asthma (Quebec, Canada, 1998-2008). A methodologically oriented objective was to comprehensively describe the application of a Bayesian 2-component mixture-of-bivariate-regressions model to address this issue and estimate the effects of ICS on GA and BW jointly. Based on the proposed model, no association between ICS and GA/BW was found for a large proportion of asthmatic pregnancies. However, a positive association between ICS exposure and GA/BW was revealed in a small subset of pregnancies comprising mainly preterm and low-birth-weight infants. A novel application of this model was also subsequently performed using BW z score instead of BW as the outcome variable. In conclusion, the studied mixture-of-bivariate-regressions model was useful for detecting heterogeneity in the effect of ICS on GA and BW in our population of women with asthma. These analyses pave the way for analogous uses of this model for general assessment of exposure effect heterogeneity for these perinatal outcomes.

mHealth resources for asthma and pregnancy care: Methodological issues and social media recruitment. A discussion paper

AIMS

A discussion of methodological issues and social media recruitment to a feasibility study to investigate mHealth resources for asthma and pregnancy care.

BACKGROUND

Pregnant women with asthma are reported to be poorly supported according to an international research. We sought to establish if a mHealth intervention might be feasible and acceptable to them.

DESIGN

A Phase I or modelling study.

METHODS

A project team designed an intervention to address UK national guidelines for the management of asthma during pregnancy, using other resources already accessible on the web. This was made available on a project website optimized for mobile phone usage. Links were Tweeted and advertised on Facebook, asking participants to access the project website, which included links to the resources and before- and after-use questionnaires to establish baseline symptom data and participant views of the resources.

RESULTS

Despite 55,700 Twitter impressions in a 76-day period over winter 2016-2017, this recruitment strategy garnered 402 engagements but only seven respondents for questionnaire 1 and zero respondents for questionnaire 2.

CONCLUSIONS

We could not recruit to this study despite believing that social media recruitment would be effective and we recommend that social media recruitment be used cautiously. Apparently, we did not sufficiently address the theoretical aspects of communications theory and were not clear enough about our key messages. Publication bias may exist about the non-publication of other failed telemedicine studies using social media; this goes largely unreported in some systematic reviews and may influence researchers' decision-making about social media recruitment.

Prospective cohort study of pregnancy complications and birth outcomes in women with asthma

Background

Asthma is the most common potentially serious medical complication in pregnancy. The purpose of this study was to determine the association between maternal asthma and a spectrum of adverse neonatal and maternal outcomes.

Methods

Events during pregnancy and birth outcome were evaluated in 34 asthmatic as well as 1569 non-asthmatic pregnant women who were enrolled in a prospective cohort study undertaken at the antenatal clinics of Mobini Hospital in Iran. The women were interviewed and classified according to clinical severity and asthma control as per GINA guidelines. Information on asthma symptoms was collected by a questionnaire as well as by spirometry and physical examination. All subjects were followed until delivery, and postpartum charts were reviewed to assess neonatal and maternal outcomes. Eosinophil cells counts were obtained and total IgE was measured by ELISA. Results were assessed by multivariate logistic regression adjusting for maternal age and parity, and for birth outcomes, for gestational diabetes, and hypertension/pre-eclampsia.

Results

The well-known relationship between family history of asthma and asthma in pregnancy was again supported (p < 0.001). Women with asthma had more bleeding events 3 weeks or more before delivery (OR 3.30, 95% CI 1.41–7.26), more often placenta problems (OR 6.86, 95% CI 1.42–33.02), and gestational diabetes mellitus (OR 3.82, 95% CI 1.06–13.75). No significant differences between asthmatic and non-asthmatic mothers regarding duration of gestation, birthweight, low Apgar scores, or neonatal respiratory difficulties were found. Total IgE antibody levels and eosinophil counts did not differ by asthma control and severity.

Conclusions

Asthma in pregnancy poses some risk for pregnancy complications and adverse perinatal outcomes. Managing asthma effectively throughout pregnancy could benefit women and their babies and help to reduce the health burden associated with asthma during pregnancy.

The course of asthma during pregnancy in a recent, multicase-control study on respiratory health

Background

Over the years it has been widely stated that approximately one-third of asthmatic women experience worsening of the disease during pregnancy. However, the literature has not been reviewed systematically and the meta-analytic reviews include old studies. This study aimed to examine whether the prevalence of worsening asthma during pregnancy is still consistent with prior estimate or it has been reduced.

Methods

A detailed Clinical Questionnaire on respiratory symptoms, medical history, medication, use of services, occupation, social status, home environment and lifestyle was administered to random samples of the Italian population in the frame of the Gene Environment Interactions in Respiratory Diseases (GEIRD) study. Only clinical data belong to 2.606 subjects that completed the clinical stage of the GEIRD study, were used for the present study.

Results

Out of 1.351 women, 284 self-reported asthma and 92 of them had at least one pregnancy. When we considered the asthma course during pregnancy, we found that 16 women worsened, 31 remained unchanged, 25 improved. Seven women had not the same course in the different pregnancies and 13 did not know. The starting age of ICS use almost overlaps with that of asthma onset in women with worsening asthma during pregnancy (19 years ± 1.4), unlike the other women who started to use ICS much later (30.3 years ± 12). In addition, the worsening of asthma was more frequent in women with an older age of onset of asthma (18 years ± 9 vs 13 years ± 10). Among women who completed the ACT during the clinical interview, the 50% of women who experienced worsening asthma during pregnancy (6/12) had an ACT score below 20.

Conclusion

Asthma was observed to worsen during pregnancy in a percentage much lower to that generally reported in all the previous studies. There is still room in clinical practice to further reduce worsening of asthma during pregnancy by improving asthma control, with a more structured approach to asthma education and management prepregnancy.

Downregulation of L-Type Voltage-Gated Ca2+, Voltage-Gated K+, and Large-Conductance Ca2+-Activated K+ Channels in Vascular Myocytes From Salt-Loading Offspring Rats Exposed to Prenatal Hypoxia

Background

Prenatal hypoxia is suggested to be associated with increased risks of hypertension in offspring. This study tested whether prenatal hypoxia resulted in salt‐sensitive offspring and its related mechanisms of vascular ion channel remodeling.

Methods and Results

Pregnant rats were housed in a normoxic (21% O₂) or hypoxic (10.5% O₂) chamber from gestation days 5 to 21. A subset of male offspring received a high‐salt diet (8% NaCl) from 4 to 12 weeks after birth. Blood pressure was significantly increased only in the salt‐loading offspring exposed to prenatal hypoxia, not in the offspring that received regular diets and in control offspring provided with high‐salt diets. In mesenteric artery myocytes from the salt‐loading offspring with prenatal hypoxia, depolarized resting membrane potential was associated with decreased density of L‐type voltage‐gated Ca²⁺ (Cav1.2) and voltage‐gated K⁺ channel currents and decreased calcium sensitive to the large‐conductance Ca²⁺‐activated K⁺ channels. Protein expression of the L‐type voltage‐gated Ca²⁺ α1C subunit, large‐conductance calcium‐activated K⁺ channel (β1, not α subunits), and voltage‐gated K⁺ channel (K_V2.1, not K_V1.5 subunits) was also decreased in the arteries of salt‐loading offspring with prenatal hypoxia.

Conclusions

The results demonstrated that chronic prenatal hypoxia may program salt‐sensitive hypertension in male offspring, providing new information of ion channel remodeling in hypertensive myocytes. This information paves the way for early prevention and treatments of salt‐induced hypertension related to developmental problems in fetal origins.

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.

Chronic hypoxia alters maternal uterine and fetal hemodynamics in the full-term pregnant guinea pig

Placental hypoxia is associated with maternal hypertension, placental insufficiency, and fetal growth restriction. In the pregnant guinea pig, prenatal hypoxia during early gestation inhibits cytotrophoblast invasion of spiral arteries, increases maternal blood pressure, and induces fetal growth restriction. In this study the impact of chronic maternal hypoxia on fetal heart structure was evaluated using four-dimensional echocardiography with spatiotemporal image correlation and tomographic ultrasound, and uterine and umbilical artery resistance/pulsatility indexes and fetal heart function were evaluated using pulsed-wave Doppler ultrasound. Pregnant guinea pigs were exposed to normoxia (n = 7) or hypoxia (10.5% O₂, n = 9) at 28-30 days gestation, which was maintained until full term (65 days). At full term, fetal heart structure and outflow tracts were evaluated in the four-chamber view. Fetal heart diastolic function was assessed by E wave-to-A wave diastolic filling ratios (E/A ratios) of both ventricles and systolic function by the myocardial performance index (or Tie) of left ventricles of normoxic (n = 21) and hypoxic (n = 17) fetuses. There were no structural abnormalities in fetal hearts. However, hypoxia induced asymmetric fetal growth restriction and increased the placental/fetal weight compared with normoxic controls. Hypoxia increased Doppler resistance and pulsatility indexes in the uterine, but not umbilical, arteries, had no effect on the Tie index, and increased the E/A ratio in left, but not right, ventricles. Thus, prolonged hypoxia, starting at midgestation, increases uterine artery resistance and generates fetal growth restriction at full term. Furthermore, the enhanced cardiac diastolic filling with no changes in systolic function or umbilical artery resistance suggests that the fetal guinea pig systemic circulation undergoes a compensated, adaptive response to prolonged hypoxia exposure.

Fetal in vivo continuous cardiovascular function during chronic hypoxia

Although the fetal cardiovascular defence to acute hypoxia and the physiology underlying it have been established for decades, how the fetal cardiovascular system responds to chronic hypoxia has been comparatively understudied. We designed and created isobaric hypoxic chambers able to maintain pregnant sheep for prolonged periods of gestation under controlled significant (10% O2) hypoxia, yielding fetal mean P(aO2) levels (11.5 ± 0.6 mmHg) similar to those measured in human fetuses of hypoxic pregnancy. We also created a wireless data acquisition system able to record fetal blood flow signals in addition to fetal blood pressure and heart rate from free moving ewes as the hypoxic pregnancy is developing. We determined in vivo longitudinal changes in fetal cardiovascular function including parallel measurement of fetal carotid and femoral blood flow and oxygen and glucose delivery during the last third of gestation. The ratio of oxygen (from 2.7 ± 0.2 to 3.8 ± 0.8; P < 0.05) and of glucose (from 2.3 ± 0.1 to 3.3 ± 0.6; P < 0.05) delivery to the fetal carotid, relative to the fetal femoral circulation, increased during and shortly after the period of chronic hypoxia. In contrast, oxygen and glucose delivery remained unchanged from baseline in normoxic fetuses. Fetal plasma urate concentration increased significantly during chronic hypoxia but not during normoxia (Δ: 4.8 ± 1.6 vs. 0.5 ± 1.4 μmol l(-1), P<0.05). The data support the hypotheses tested and show persisting redistribution of substrate delivery away from peripheral and towards essential circulations in the chronically hypoxic fetus, associated with increases in xanthine oxidase-derived reactive oxygen species.

In utero Programming of Allergic Susceptibility

BACKGROUND

Around 30-40% of the world's population will experience allergy, the most common and earliest-onset noncommunicable disease. With a steady rise in the incidence of allergic disease over recent decades, up to 18% of children will suffer a respiratory, food or skin allergy before their 18th birthday. There is compelling evidence that the risk of developing allergy is influenced by early life events and particularly in utero exposures.

METHODS

A comprehensive literature review was undertaken which outlines prenatal risk factors and potential mechanisms underlying the development of allergy in childhood.

RESULTS

Exposures including maternal cigarette smoking, preterm birth and Caesarean delivery are implicated in predisposing infants to the later development of allergy. In contrast, restricted growth in utero, a healthy maternal diet and a larger family size are protective, but the mechanisms here are unclear and require further investigation.

CONCLUSION

To ameliorate the allergy pandemic in young children, we must define prenatal mechanisms that alter the programming of the fetal immune system and also identify specific targets for antenatal interventions.

The fetal brain sparing response to hypoxia: physiological mechanisms

How the fetus withstands an environment of reduced oxygenation during life in the womb has been a vibrant area of research since this field was introduced by Joseph Barcroft, a century ago. Studies spanning five decades have since used the chronically instrumented fetal sheep preparation to investigate the fetal compensatory responses to hypoxia. This defence is contingent on the fetal cardiovascular system, which in late gestation adopts strategies to decrease oxygen consumption and redistribute the cardiac output away from peripheral vascular beds and towards essential circulations, such as those perfusing the brain. The introduction of simultaneous measurement of blood flow in the fetal carotid and femoral circulations by ultrasonic transducers has permitted investigation of the dynamics of the fetal brain sparing response for the first time. Now we know that major components of fetal brain sparing during acute hypoxia are triggered exclusively by a carotid chemoreflex and that they are modified by endocrine agents and the recently discovered vascular oxidant tone. The latter is determined by the interaction between nitric oxide and reactive oxygen species. The fetal brain sparing response matures as the fetus approaches term, in association with the prepartum increase in fetal plasma cortisol, and treatment of the preterm fetus with clinically relevant doses of synthetic steroids mimics this maturation. Despite intense interest into how the fetal brain sparing response may be affected by adverse intrauterine conditions, this area of research has been comparatively scant, but it is likely to take centre stage in the near future.

Interventions for managing asthma in pregnancy

BACKGROUND

Asthma is the most common respiratory disorder complicating pregnancy, and is associated with a range of adverse maternal and perinatal outcomes. There is strong evidence however, that the adequate control of asthma can improve health outcomes for mothers and their babies. Despite known risks of poorly controlled asthma during pregnancy, a large proportion of women have sub-optimal asthma control, due to concerns surrounding risks of pharmacological agents, and uncertainties regarding the effectiveness and safety of different management strategies.

OBJECTIVES

To assess the effects of interventions (pharmacologic and non-pharmacologic) for managing women's asthma in pregnancy on maternal and fetal/infant outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (2 June 2014) and the Cochrane Airways Group's Trials Register (4 June 2014).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing any intervention used to manage asthma in pregnancy, with placebo, no intervention, or an alternative intervention. We included pharmacological and non-pharmacological interventions (including combined interventions). Cluster-randomised trials were eligible for inclusion (but none were identified). Cross-over trials were not eligible for inclusion.We included multi-armed trials along with two-armed trials. We also included studies published as abstracts only.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed trial eligibility and quality and extracted data. Data were checked for accuracy.

MAIN RESULTS

We included eight trials in this review, involving 1181 women and their babies. Overall we judged two trials to be at low risk of bias, two to be of unclear risk of bias, and four to be at moderate risk of bias.Five trials assessed pharmacological agents, including inhaled corticosteroids (beclomethasone or budesonide), inhaled magnesium sulphate, intravenous theophylline, and inhaled beclomethasone verus oral theophylline. Three trials assessed non-pharmacological interventions, including a fractional exhaled nitric oxide (FENO)-based algorithm versus a clinical guideline-based algorithm to adjust inhaled corticosteroid therapy, a pharmacist-led multi-disciplinary approach to management versus standard care, and progressive muscle relaxation (PMR) versus sham training.The eight included trials were assessed under seven separate comparisons. Pharmacological interventionsPrimary outcomes: one trial suggested that inhaled magnesium sulphate in addition to usual treatment could reduce exacerbation frequency in acute asthma (mean difference (MD) -2.80; 95% confidence interval (CI) -3.21 to -2.39; 60 women). One trial assessing the addition of intravenous theophylline to standard care in acute asthma did not report on exacerbations (65 women). No clear difference was shown in the risk of exacerbations with the use of inhaled beclomethasone in addition to usual treatment for maintenance therapy in one trial (risk ratio (RR) 0.36; 95% CI 0.13 to 1.05; 60 women); a second trial also showed no difference, however data were not clearly reported to allow inclusion in a meta-analysis. No difference was shown when inhaled beclomethasone was compared with oral theophylline for maintenance therapy (RR 0.88; 95% CI 0.59 to 1.33; one trial, 385 women). None of these trials reported on neonatal intensive care admissions.

SECONDARY OUTCOMES

inhaled magnesium sulphate in acute asthma was shown to improve lung function measures (one trial, 60 women); intravenous theophylline in acute asthma was not associated with benefits (one trial, 65 women). No clear differences were seen with the addition of inhaled corticosteroids to routine treatment in three trials (374 women). While inhaled beclomethasone, compared with oral theophylline, significantly reduced treatment discontinuation due to adverse effects in one trial (384 women), no other differences were observed, except for higher treatment adherence with theophylline. Four of the five trials did not report on adverse effects. Non-pharmacological interventionsPrimary outcomes: in one trial, the use of a FENO-based algorithm was shown to significantly reduce asthma exacerbations (RR 0.61; 95% CI 0.41 to 0.90; 220 women); and a trend towards fewer neonatal hospitalisations was observed (RR 0.46; 95% CI 0.21 to 1.02; 214 infants). No exacerbations occurred in one trial assessing pharmacist-led management; this approach did not reduce neonatal intensive care admissions (RR 1.50; 95% CI 0.27 to 8.32; 58 infants). One trial (64 women) assessing PMR did not report on exacerbations or neonatal intensive care admissions.

SECONDARY OUTCOMES

the use of a FENO-based algorithm to adjust therapy led to some improvements in quality of life scores, as well as more frequent use of inhaled corticosteroids and long-acting β-agonists, and less frequent use of short-acting β-agonists (one trial, 220 women). The FENO-based algorithm was associated with fewer infants with recurrent episodes of bronchiolitis in their first year of life, and a trend towards fewer episodes of croup for infants. Pharmacist-led management improved asthma control scores at six months (one trial, 60 women); PMR improved lung function and quality of life measures (one trial, 64 women). No other differences between comparisons were observed.

AUTHORS' CONCLUSIONS

Based on eight included trials, of moderate quality overall, no firm conclusions about optimal interventions for managing asthma in pregnancy can be made. Five trials assessing pharmacological interventions did not provide clear evidence of benefits or harms to support or refute current practice. While inhaled magnesium sulphate for acute asthma was shown to reduce exacerbations, this was in one small trial of unclear quality, and thus this finding should be interpreted with caution. Three trials assessing non-pharmacological interventions provided some support for the use of such strategies, however were not powered to detect differences in important maternal and infant outcomes. While a FENO-based algorithm reduced exacerbations, the effects on perinatal outcomes were less certain, and thus widespread implementation is not yet appropriate. Similarly, though positive effects on asthma control were shown with PMR and pharmacist-led management, the evidence to date is insufficient to draw definitive conclusions.In view of the limited evidence base, further randomised trials are required to determine the most effective and safe interventions for asthma in pregnancy. Future trials must be sufficiently powered, and well-designed, to allow differences in important outcomes for mothers and babies to be detected. The impact on health services requires evaluation. Any further trials assessing pharmacological interventions should assess novel agents or those used in current practice. Encouragingly, at least five trials have been identified as planned or underway.

Association of maternal diabetes and child asthma

BACKGROUND

Perinatal programming is an emerging theory for the fetal origins of chronic disease. Maternal asthma and environmental tobacco smoke (ETS) are two of the best-known triggers for the perinatal programming of asthma, while the potential role of maternal diabetes has not been widely studied.

OBJECTIVE

To determine if maternal diabetes is associated with child asthma, and if so, whether it modifies the effects of ETS exposure and maternal asthma.

METHODS

We studied 3,574 Canadian children, aged 7-8 years, enrolled in a population-based birth cohort. Standardized questionnaires were completed by the children's parents, and data were analyzed by multivariable logistic regression.

RESULTS

Asthma was reported in 442 children (12.4%). Compared to those without asthma, asthmatic children were more likely to have mothers (P = 0.003), but not fathers (P = 0.89), with diabetes. Among children without maternal history of diabetes, the likelihood of child asthma was 1.4-fold higher in those exposed to ETS (adjusted odds ratio, 1.40; 95% confidence interval, 1.13-1.73), and 3.6-fold higher in those with maternal asthma (3.59; 2.71-4.76). Among children born to diabetic mothers, these risks were amplified to 5.7-fold (5.68; 1.18-27.37) and 11.3-fold (11.30; 2.26-56.38), respectively. In the absence of maternal asthma or ETS, maternal diabetes was not associated with child asthma (0.65, 0.16-2.56).

CONCLUSION

Our findings suggest that maternal diabetes may contribute to the perinatal programming of child asthma by amplifying the detrimental effects of ETS exposure and maternal asthma.

Asthma in pregnancy: a review

Asthma is one of the most common medical conditions in women of childbearing age. There are now data to show that asthma is not a benign condition with respect to maternal and fetal health. Despite this there are several problems encountered in the management of such women. There is a tendency to cease or reduce optimal asthma treatments because pregnant women and/or their clinicians may believe they pose a risk to the fetus. There is also a lack of clinician awareness of the complications of asthma in pregnancy.

Pretreatment levels of circulating Th1 and Th2 cytokines, and their ratios, are associated with ER-negative and triple negative breast cancers

Immune signatures in breast tumors differ by estrogen receptor (ER) status. The purpose of this study was to assess associations between ER phenotypes and circulating levels of cytokines that co-ordinate cell-mediated [T-helper type 1 (Th1)] and humoral [T-helper type 2 (Th2)] immunity. We conducted a case-case comparison of 523 women with newly diagnosed breast cancer to evaluate associations between 27 circulating cytokines, measured using Luminex XMap technology, and breast cancer phenotypes [ER(-) vs. ER(+); triple negative breast cancer (TNBC) vs. luminal A (LumA)]. Ratios of Th1 to Th2 cytokines were also evaluated. Levels of interleukin (IL)-5, a Th-2 cytokine, were higher in ER(-) than in ER(+) tumors. The highest tertile of IL-5 was more strongly associated with ER(-) (OR = 2.33, 95 % CI 1.40-3.90) and TNBCs (OR = 2.78, 95 % CI 1.53-5.06) compared to ER(+) and LumA cancers, respectively, particularly among premenopausal women (OR = 4.17, 95 % CI 1.86-9.34, ER(-) vs. ER(+); OR = 5.60, 95 % CI 2.09-15.01, TNBC vs. LumA). Elevated Th1 cytokines were also detected in women with ER(-) and TNBCs, with women in the highest tertile of interferon α2 (OR = 2.39, 95 % CI 1.31-4.35) or tumor necrosis factor-α (OR = 2.27, 95 % CI 1.21-4.26) being twice as likely to have TNBC versus LumA cancer. When cytokine ratios were examined, women with the highest ratios of Th1 cytokines to IL-5 levels were least likely to have ER(-) or TNBCs compared to ER(+) or LumA cancers, respectively. The strongest associations were in premenopausal women, who were up to 80 % less likely to have TNBC than LumA cancers (IL-12p40/IL-5, OR = 0.19, 95 % CI 0.07-0.56). These findings indicate that immune function is associated with ER(-) and TNBC and may be most relevant among younger women, who are likely to be diagnosed with these aggressive phenotypes.

Asthma and endocrine disorders: shared mechanisms and genetic pleiotropy

Asthma is a common inflammatory disease for which the cause is not yet known. Studies of the epidemiology and natural history of childhood asthma into adulthood demonstrate a change in gender prevalence with age. Hormones and inflammation may interact in asthma pathogenesis and determine its course. The same may be true for some endocrine disorders, including diabetes and obesity. Obesity plays a major role in the development of the metabolic syndrome and has been identified as an important risk factor for chronic diseases such as type 2 diabetes mellitus. The prevalence of asthma has paralleled the rise in obesity, suggesting that shared environmental factors could affect both conditions. In addition, endocrine diseases and asthma may share common genetic determinants. In the first part of this review we assess endocrine influences on asthma and overlaps between endocrine disorders and asthma while in the second part we explore the potential benefit of comparative genetic analyses between asthma and endocrine diseases.