Maternal asthma during pregnancy and extremes of body mass index increase the risk of perinatal mortality: a retrospective cohort study

Maternal asthma during pregnancy and risks of allergy and asthma in progeny: A systematic review and meta-analysis

BACKGROUND

Clinical and preclinical evidence indicate that in utero maternal asthma exposure increases progeny asthma risk. Whether maternal asthma also increases the risks of progeny allergy is unclear.

OBJECTIVES

To synthesise the available evidence on the relationship between in utero exposure to maternal asthma and postnatal asthma, wheezing and allergic diseases (Prospero: CRD42020201538).

SEARCH STRATEGY

We systematically searched MEDLINE [PubMed], Embase [Ovid], Web of Science, Informit Health, the Cochrane Library, CINAHL [EBSCOhost], MedNar [Deep Web Technologies], ProQuest Theses and Dissertations, Scopus [Elsevier] and Trove, to the end of 2023.

SELECTION CRITERIA

Studies reporting asthma, wheeze and/or allergic disease in progeny of women with and without asthma or with asthma classified by control, exacerbation or severity.

DATA COLLECTION AND ANALYSIS

Double screening, selection, data extraction and quality assessment were performed, using Joanna Briggs Institute (JBI) scoring.

MAIN RESULTS

Of 134 non-overlapping studies, 127 were included in ≥1 meta-analysis. Maternal asthma ever was associated with greater risks of asthma (65 studies, risk ratio [95% confidence interval] 1.76 [1.57-1.96]), wheeze (35 studies, 1.59 [1.52-1.66]), food allergy (5 studies, 1.32 [1.23-1.40]), allergic rhinitis (7 studies, 1.18 [1.06-1.31]) and allergic dermatitis (14 studies, 1.17 [1.11-1.23]) ever in progeny. Asthma during the pregnancy, more severe, and uncontrolled maternal asthma were each associated with greater risks of progeny asthma.

CONCLUSIONS

Children of mothers with asthma are at increased risk for the development of allergic diseases. Whether improved maternal asthma control reduces risks of child allergy as well as asthma requires further investigation.

Treatable Traits in Pregnant Women with Asthma

BACKGROUND

Asthma is the most common chronic respiratory disease in pregnancy, affecting approximately 8-10% of pregnant women. Uncontrolled asthma is associated with adverse perinatal outcomes, including low birth weight, preterm birth, and maternal complications such as pre-eclampsia.

SUMMARY

A current approach to the management of chronic airway diseases is based on targeting treatable traits. The aim of this review was to define treatable traits in pregnant women with asthma based on recent literature and to determine personalized treatment options according to these traits. Traits addressed in this review that may improve asthma control and pregnancy outcomes are fractional exhaled nitric oxide-based asthma monitoring and treatment, medication adherence and inhalation technique, impaired lung function, smoking cessation and comorbidity including psychological conditions (depression and anxiety), obesity, rhinitis, gastroesophageal reflux disease, chronic rhinosinusitis with or without nasal polyps, and sleep apnea.

KEY MESSAGES

All the treatable traits discussed have the potential to improve asthma control and pregnancy outcomes in pregnant women with asthma. Further research is needed to determine which management approaches are best to improve asthma control during pregnancy, to identify other relevant treatable traits, and to determine whether the treatable trait approach is feasible and beneficial in pregnant women with asthma.

Preclinical models of maternal asthma and progeny outcomes: a scoping review

There is an increased risk of adverse perinatal outcomes in the ∼17% of women with asthma during pregnancy. The mechanisms linking maternal asthma and adverse outcomes are largely unknown, but reflect joint effects of genetics and prenatal exposure to maternal asthma. Animal models are essential to understand the underlying mechanisms independent of genetics and comorbidities, and enable safe testing of interventions. This scoping review aimed to explore the methodology, phenotype, characteristics, outcomes and quality of published studies using preclinical maternal asthma models. MEDLINE (PubMed), Embase (Elsevier) and Web of Science were systematically searched using previously validated search strings for maternal asthma and for animal models. Two reviewers independently screened titles and abstracts, full texts, and then extracted and assessed the quality of each study using the Animal Research: Reporting of In Vivo Experiments (ARRIVE) 2.0 guidelines. Out of 3618 studies identified, 39 were eligible for extraction. Most studies were in rodents (86%) and all were models of allergic asthma. Maternal and progeny outcomes included airway hyperresponsiveness, airway resistance, inflammation, lung immune cells, lung structure and serum immunoglobulins and cytokines. Experimental design (100%), procedural details (97%) and rationale (100%) were most often reported. Conversely, data exclusion (21%), blinding (18%) and adverse events (8%) were reported in a minority of studies. Species differences in physiology and timing of development, the use of allergens not relevant to humans and a lack of comparable outcome measures may impede clinical translation. Future studies exploring models of maternal asthma should adhere to the minimum core outcomes set presented in this review.

The impact of maternal asthma on the fetal lung: Outcomes, mechanisms and interventions

Maternal asthma affects up to 17% of pregnancies and is associated with adverse infant, childhood, and adult respiratory outcomes, including increased risks of neonatal respiratory distress syndrome, childhood wheeze and asthma. In addition to genetics, these poor outcomes are likely due to the mediating influence of maternal asthma on the in-utero environment, altering fetal lung and immune development and predisposing the offspring to later lung disease. Maternal asthma may impair glucocorticoid signalling in the fetus, a process critical for lung maturation, and increase fetal exposure to proinflammatory cytokines. Therefore, interventions to control maternal asthma, increase glucocorticoid signalling in the fetal lung, or Vitamin A, C, and D supplementation to improve alveologenesis and surfactant production may be beneficial for later lung function. This review highlights potential mechanisms underlying maternal asthma and offspring respiratory morbidities and describes how pregnancy interventions can promote optimal fetal lung development in babies of asthmatic mothers.

Preclinical models of maternal asthma and progeny outcomes: a scoping review protocol

OBJECTIVE

This scoping review will describe the methodology, phenotype, and characteristics of maternal asthma models used in preclinical studies and the outcomes that have been measured in the mother and progeny. The review This will identify gaps in knowledge of maternal and progeny outcomes following maternal asthma in pregnancy.

INTRODUCTION

Maternal asthma affects up to 17% of pregnancies worldwide and is associated with adverse perinatal outcomes in mothers and babies, including pre-eclampsia, gestational diabetes, cesarean section, preterm birth, small for gestational age, nursery admission, and neonatal death. While the associations are well established, the mechanisms linking maternal asthma and adverse perinatal outcomes are largely unknown due to the difficulties of human mechanistic studies. The appropriate selection of animal models is vital to understanding the mechanisms underlying associations between human maternal asthma and adverse perinatal outcomes.

INCLUSION CRITERIA

This review will include primary studies published in English where outcomes have been studied in vivo in non-human mammalian species.

METHODS

This review will follow the JBI methodology for scoping reviews. We will search MEDLINE (PubMed), Embase, and Web of Science to identify papers published before the end of 2022. Initial keywords will include pregnancy, gestation, asthma , and wheeze , as well as validated search strings to identify papers that describe animal models. Extracted data will include information on methods used to induce maternal asthma; asthmatic phenotypes and characteristics; and maternal, pregnancy, placental, and progeny outcomes. The characteristics of each study will be presented in summary tables and a core outcome list to assist researchers in developing, reporting, and comparing future animal studies of maternal asthma.

REVIEW REGISTRATION

Open Science Framework osf.io/trwk5.

The impact of obesity and uncontrolled asthma during pregnancy on metabolic and inflammatory pathways

Asthma and obesity are both inflammatory complications of pregnancy and when combined contribute to an increased risk of uncontrolled asthma during pregnancy and poor perinatal outcomes. Our previous work has identified the presence of maternal asthma is associated with a proinflammatory milieu in the placenta and reduced fetal growth. The current study was designed to determine the relationships between immunomodulatory metabolic pathways and inflammation and establish whether these pathways are associated with uncontrolled asthma in obese pregnant women.Fifty-three obese (BMI >30) pregnant women were recruited prospectively. Participants were classified as having no asthma, controlled asthma, and uncontrolled asthma based on a doctor diagnosis and assessment using the Asthma Control Questionnaire (ACQ). Circulating plasma concentrations of metabolic hormones leptin, adiponectin, insulin, glucose, and extracellular vesicle (EVs) associated cytokines were measured at 18- and 36-weeks gestation.Concentrations of metabolic and inflammatory markers among obese participants with or without asthma were not significantly different throughout gestation. However total adiponectin concentrations increased as gestation progressed in obese, non-asthmatic women but did not increase in women with asthma. Plasma adiponectin and leptin levels in women with uncontrolled asthma were positively correlated with EV inflammatory markers including GM-CSF, IL-6, TNFα and IFNγ protein.This study demonstrated that most metabolic markers remain unchanged with the presence and severity of asthma in obese pregnant women. However, differences in the associations between metabolic and inflammatory pathways were observed in women with asthma and may be one of the mechanisms contributing to uncontrolled asthma in obese pregnant women.

Challenges in the successful management of asthma during conception, pregnancy and delivery

Asthma and infertility are the most common disorders among women of reproductive age. Time to pregnancy is prolonged in women with asthma, and importantly, age seems to be a more important risk factor regarding fertility in women with asthma compared to women without asthma. Some data have shown a higher frequency of miscarriages in women with asthma, although the data are conflicting on this issue as studies have observed no association between asthma and pregnancy loss. Furthermore, studies have shown no negative effect of asthma on the total number of offspring. Pregnancy may, thus, have a significant impact on women with asthma, as well as on their offspring.

The age of the women has an important impact on ability to conceive, but also for the pregnancy itself, with higher risk of uncontrolled asthma as well as asthma exacerbations with increasing age. Well-controlled asthma decreases the risk of maternal and fetal complications, while poorly controlled and undertreated asthma is associated with a range of risks for both mother and fetus. Asthma treatment should follow the general guidelines for asthma therapy, irrespective of pregnancy status, including treatment with inhaled corticosteroids, β2-agonists and muscarinic antagonists. Targeted treatment with biologics for severe asthma seems to be without important adverse effects. The use of systemic corticosteroids may be associated with adverse events during the first trimester; however, an exacerbation with the associated risk of hypoxaemia is worse for the fetus. Best possible asthma control may be achieved using repeated measurements of fractional exhaled nitric oxide (FENO), as the use of FENO compared with symptoms registration only has been shown to reduce exacerbation rate.

In conclusion, women with asthma should be encouraged to conceive at an early age, might experience miscarriages, but the number of offspring are the same as in women without asthma. Well treated asthma is important for the well-being of both the mother and the unborn fetus.