The impact of maternal asthma during pregnancy on fetal growth and development: a review

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.

Asthma in Pregnancy: A Critical Review of Impact, Management, and Outcomes

Asthma is a common chronic respiratory condition that can significantly impact the health of pregnant women and their developing fetuses. This comprehensive review provides insights into the prevalence of asthma in pregnant women, the physiological changes during pregnancy, and the multifaceted impact of asthma on maternal and fetal health. It emphasizes the importance of proper asthma diagnosis, medication management, and the development of personalized asthma action plans during pregnancy. Lifestyle modifications, trigger avoidance, and stress reduction are essential to effective management. Healthcare providers are pivotal in educating, monitoring, and individualized care to ensure optimal asthma control. The review underscores the critical significance of managing asthma during pregnancy, as it improves maternal and fetal outcomes and potentially influences long-term health for both mother and child. Future directions in this field involve ongoing research, personalized treatment, early intervention, and precision medicine to enhance the understanding and care of asthma during pregnancy.

Maternal asthma in relation to infant size and body composition

Background

Asthma affects 10% of pregnancies and may influence offspring health, including infant size and body composition, through hypoxic and inflammatory pathways.

Objective

We sought to determine associations between maternal asthma and asthma phenotypes during pregnancy and infant size and body composition.

Methods

The B-WELL-Mom study (2015-19) is a prospective cohort of 418 pregnant persons with and without asthma recruited in the first trimester of pregnancy from 2 US obstetric clinics. Exposures were maternal self-reported active asthma (n = 311) or no asthma (n = 107), and asthma phenotypes were classified on the bases of atopy, onset, exercise induced, control, severity, symptomology, and exacerbations. Outcomes were infant weight, length, head circumference, and skinfold measurements at birth and postnatal follow-up, as well as fat and lean mass assessed by air displacement plethysmography at birth. Adjusted multivariable linear regression examined associations of maternal asthma and asthma phenotypes with infant outcomes.

Results

Offspring were born at a mean ± SD of 38 ± 2.3 weeks' gestation and were 18 ± 2.2 weeks of age at postnatal follow-up. Infants of participants with asthma had a mean ± SD fat mass of 11.0 ± 4.2%, birth weight of 3045.8 ± 604.3 g, and postnatal follow-up weight of 6696.4 ± 964.2 g, which were not different from infants of participants without asthma (respectively, β [95% confidence interval]: -0.1 [-1.4, 1.3], -26.7 [-156.9, 103.4], and 107.5 [-117.3, 332.3]). Few associations were observed between asthma or asthma phenotypes and infant size or body composition.

Conclusions

In a current obstetric cohort, maternal asthma during pregnancy was not associated with differential infant size or body composition.

Prenatal exposure to perceived stress, maternal asthma, and placental size

INTRODUCTION

Prenatal exposure to stress has been associated with poor pregnancy outcomes, yet evidence linking stress and placental size is limited. Asthma is associated with worse pregnancy outcomes and women with asthma may be more susceptible to stress. Using the asthma-enriched B-WELL-Mom cohort, we examined the association between perceived stress and placental size.

METHODS

Placental measures of weight, length, width, and thickness were available for 345 women (262 with asthma) via placental pathology report. Perceived Stress Scale (PSS) scores were obtained in each trimester of pregnancy and categorized into quartiles (low quartile as reference). For associations between PSS and placental size, generalized estimating equations adjusted for maternal and infant factors were used to estimate regression coefficients (β) and 95% confidence intervals (95% CI). Full models and models stratified by asthma status were run.

RESULTS

Compared to Quartile 1, high levels of stress (Quartile 4) were associated with smaller placental weight (-20.63 95% CI: -37.01,-4.26) and length (-0.55 95% CI: -0.96,-0.15), but not width or thickness. Results by asthma status show a stronger association between perceived stress and shorter placental length in those with asthma and a stronger association between perceived stress and smaller placental thickness in those without asthma. Findings were robust to sensitivity analyses DISCUSSION: Higher levels of perceived stress were associated with smaller placental size. Additional research is warranted to understand the relationship between stress and placental size.

Association of Maternal Asthma and Total Serum Immunoglobulin E levels with Obstetric Complications: The Japan Environment and Children's Study

OBJECTIVE

To evaluate the association between maternal asthma (MA) and obstetric complications, while considering subdivided total serum immunoglobulin E (IgE) levels.

METHODS

Data of the participants enrolled in the Japan Environment and Children's Study between 2011 and 2014 were analyzed. In total, 77,131 women with singleton live births at and after 22 weeks of gestation were included. MA was defined based on a self-administered questionnaire. Women with MA were stratified based on the quartile of total serum IgE levels during pregnancy as follows: low IgE levels (< 52.40 IU/mL), moderate IgE levels (52.40-331.00 IU/mL), and high IgE levels (> 331.00 IU/mL). The adjusted odds ratios (aORs) for preterm births (PTB), small for gestational age (SGA) infants, gestational diabetes mellitus, and hypertensive disorders of pregnancy (HDP) were calculated using multivariable logistic regression, while considering women without MA as reference and maternal socioeconomic factors as confounders.

RESULTS

The aORs for SGA infants and HDP in women with MA and high total serum IgE levels were 1.26 (95% confidence interval [CI], 1.05-1.50) and 1.33 (95% CI, 1.06-1.66), respectively. The aOR for SGA infants among women with MA and moderate total serum IgE levels was 0.85 (95% CI, 0.73-0.99). The aOR for PTB among women with MA and low total serum IgE levels was 1.26 (95% CI, 1.04-1.52).

CONCLUSIONS FOR PRACTICE

MA with subdivided total serum IgE levels was associated with obstetric complications. Total serum IgE level may be a potential prognostic marker to predict obstetric complications in pregnancies with MA.

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.

The obstetric aspects of maternal asthma

Asthma is the commonest chronic medical condition encountered in pregnancy. Poor asthma control and exacerbations are frequently encountered due to treatment non-adherence, pregnancy-related aggravating factors such as increased susceptibility to viral infections, and comorbidities that are commonly associated. Asthma-related inflammatory reactions and placental effects, the effect of medications, and respiratory symptoms and hypoxia are probably to interact to result in an increased adverse obstetric outcomes including miscarriage, foetal congenital anomalies, pregnancy hypertensive disorders, gestational diabetes, preterm labour and birth, antepartum haemorrhage, low birthweight and foetal growth restriction (FGR), caesarean delivery, postpartum haemorrhage (PPH), maternal intensive care admission, and even mortality, while the offspring also has increased long-term morbidity. Interdisciplinary management with frequent assessment by symptoms, spirometry, and biomarkers, together with removal of risk factors such as smoking and appropriate instigation of treatment including short courses of systemic corticosteroid, could ensure optimal and tailored treatment to control symptoms, prevent exacerbations, and ultimately enhancing maternal and perinatal outcomes.

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

OBJECTIVE

Asthma during pregnancy and extremes of body mass index (BMI) are independently associated with adverse pregnancy outcomes but the impact of the two conditions combined are currently unknown. The aim of this study was to determine the contribution of maternal BMI to adverse birth outcomes in pregnancies complicated by asthma.

METHODS

The study utilized the routinely collected perinatal data on births at the Mater Mother's Hospital Brisbane, Australia, from January 2008 to December 2019. BMI was grouped as underweight (<18.5), normal weight (18.5-<24.99), overweight (25-29.99), and obese (≥30) and the population split by the presence and absence of maternal asthma. The comparison group was normal BMI, non-asthmatic pregnant women. A modified Poisson regression with robust variance was used to estimate the relative risk.

RESULTS

In a retrospective cohort study of 110,057 pregnant women, 17.08% of women had asthma. Asthma and BMI were associated with an increased risk of poor fetal and neonatal outcomes. Asthma significantly increased the risk of stillbirth in underweight [adjusted RR: 2.22 (95% CI: 1.25-3.94] and obese [1.74 (1.11-2.71)]; neonatal death in underweight [3.41 (1.89-6.16)] and obese [2.22 (1.37-3.59)] and perinatal death in underweight [2.34 (1.50-3.66)] and obese [1.92 (1.38-2.67)] women. Admission to the neonatal intensive care unit was increased in neonates of underweight [1.65 (1.44-1.89)] and obese [1.26 (1.14-1.40)] asthmatic women.

CONCLUSIONS

Extremes of BMI, specifically underweight and obesity, increased the risk of adverse perinatal outcomes among asthmatic women highlighting the importance of accounting for BMI during pre-conception and pregnancy related management of asthmatic women.

Early Sensory and Temperament Features in Infants Born to Mothers With Asthma: A Cross-Sectional Study

Maternal asthma in pregnancy is associated with an increased risk of adverse perinatal outcomes. Adverse perinatal outcomes may result in poorer infant developmental outcomes, such as temperament and sensory difficulties. This study aimed to (1) assess differences in temperament and sensory features between infants born to mothers with and without asthma and (2) investigate differences in these infant behaviours as a function of maternal asthma severity and asthma control. Mothers completed the Carey Temperament Scales and the Sensory Profile 2 at either 6 weeks, 6 months, or 12 months postpartum. Overall, we observed no significant differences between infants born to mothers with and without asthma in their temperament or sensory features; scores in both domains fell within the normative range. More infants in the asthma group, however, were reported to be highly distractible. When compared with normative data, infants in both groups were reported to have poor predictability of biological functions and fewer infants engaged in low levels of sensory behaviours. Some infants were observed to experience difficulties with hyper-reactivity within several domains. Maternal asthma severity and control during pregnancy were not linked to significant differences between infant temperament and sensory features. The present findings indicate that infants born to mothers with asthma are not at an increased risk overall for temperament or sensory difficulties, compared to control infants. However, a subset of infants across both groups may be at risk for attention or sensory hyper-reactivity difficulties. Further research into the developmental outcomes of infants born to mothers with asthma is warranted.

Let's Talk about Placental Sex, Baby: Understanding Mechanisms That Drive Female- and Male-Specific Fetal Growth and Developmental Outcomes

It is well understood that sex differences exist between females and males even before they are born. These sex-dependent differences may contribute to altered growth and developmental outcomes for the fetus. Based on our initial observations in the human placenta, we hypothesised that the male prioritises growth pathways in order to maximise growth through to adulthood, thereby ensuring the greatest chance of reproductive success. However, this male-specific “evolutionary advantage” likely contributes to males being less adaptable to shifts in the in-utero environment, which then places them at a greater risk for intrauterine morbidities or mortality. Comparatively, females are more adaptable to changes in the in-utero environment at the cost of growth, which may reduce their risk of poor perinatal outcomes. The mechanisms that drive these sex-specific adaptations to a change in the in-utero environment remain unclear, but an increasing body of evidence within the field of developmental biology would suggest that alterations to placental function, as well as the feto-placental hormonal milieu, is an important contributing factor. Herein, we have addressed the current knowledge regarding sex-specific intrauterine growth differences and have examined how certain pregnancy complications may alter these female- and male-specific adaptations.

A preferential switch between placental GR exon 1 promoter variants in the presence of maternal asthma or inflammation upregulates GRα D isoforms

INTRODUCTION

The human placenta expresses multiple glucocorticoid receptor (GR) isoforms that may be partially regulated by the untranslated 5' exon 1 GR gene promoter region which consists of 9 different promoters and 13 splice variants. The objective of this study was to determine which GR exon 1 variants are expressed in the human placenta and relate these findings to GR mRNA and protein expression.

METHODS

Placental extracts from pregnancies with or without the complication of maternal asthma and trophoblast cells exposed to an inflammatory challenge in vitro were examined using PCR and Western blot to measure GR exon 1 variants, GR splice variant mRNA and GR protein isoforms, respectively.

RESULTS

All 9 GR exon 1 variants were detectable in the human placenta and included GR exons 1A, 1B, 1C, 1D, 1E, 1F, 1H, 1I and 1J. In the presence of maternal asthma and a male fetus there was preferential expression of GR exon 1B, 1C, IF and 1J (KW-ANOVA, P < 0.05) which were positively correlated with GRα D3 protein isoform. In female placentae from pregnancies complicated by asthma there was no upregulation of any exon 1 variant (KW-ANOVA, P < 0.05). Exposure of BeWo trophoblast cell line to an inflammatory challenge, lipopolysaccharide, in vitro, resulted in preferential expression of GR exon 1B, 1D, 1E and 1H and associated with GRα-D1 protein upregulation.

DISCUSSION

The preferential expression of different GR exon 1 promoters drive the upregulation of GRα D isoforms and contribute to glucocorticoid resistance observed in male placentae of pregnancies complicated by asthma.