Alterations of placental vascular function in asthmatic pregnancies

Montelukast use in pregnancy: A systematic review and meta-analysis of maternal and fetal outcomes in asthma treatment

This systematic review and meta-analysis evaluated the safety of montelukast in treating asthma during pregnancy, focusing on maternal and fetal outcomes such as congenital anomalies (CA), preterm delivery, low birthweight, spontaneous abortion, gestational diabetes mellitus, and preeclampsia. A comprehensive literature search was conducted in Google Scholar, PubMed, and the Cochrane Library databases from inception until April 30, 2024. The eligible studies assessed the safety of montelukast for asthma treatment during pregnancy. The review suggests that montelukast use during pregnancy may not significantly increase the risk of major CA. The pooled results yielded risk ratio (RR) for CA was 1.13 [95% CI (0.74, 1.73), p = 0.56, I2 = 0%]. Montelukast may be associated with preterm delivery and a low birthweight odds ratio (OR) of 1.82 [95% CI (1.35, 2.45), p < 0.001, I2 = 0%]. No significant risks were found concerning neurodevelopmental outcomes. The associations with spontaneous abortion were inconclusive [OR = 1.03, 95% CI (0.72, 1.5), p = 0.86, I2 = 73%], highlighting the need for further research. This comprehensive review underscores the importance of further investigating the safety profile of montelukast during pregnancy. While the overall findings indicate a relatively favorable safety profile, especially regarding major CA, careful consideration is needed for the potential risks of preterm delivery and low birthweight.

Adverse neonatal outcomes in pregnant women with asthma: An updated systematic review and meta-analysis

BACKGROUND

A systematic review and meta-analysis from 2013 reported increased risks of congenital malformations, neonatal death and neonatal hospitalization amongst infants born to women with asthma compared to infants born to mothers without asthma.

OBJECTIVE

Our objective was to update the evidence on the associations between maternal asthma and adverse neonatal outcomes.

SEARCH STRATEGY

We performed an English-language MEDLINE, Embase, CINAHL, and COCHRANE search with the terms (asthma or wheeze) and (pregnan* or perinat* or obstet*).

SELECTION CRITERIA

Studies published from March 2012 until September 2023 reporting at least one outcome of interest (congenital malformations, stillbirth, neonatal death, perinatal mortality, neonatal hospitalization, transient tachypnea of the newborn, respiratory distress syndrome and neonatal sepsis) in a population of women with and without asthma.

DATA COLLECTION AND ANALYSIS

The study was reported following the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) and the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. Quality of individual studies was assessed by two reviewers independently using the Newcastle-Ottawa Scale. Random effects models (≥3 studies) or fixed effect models (≤2 studies) were used with restricted maximum likelihood to calculate relative risk (RR) from prevalence data and the inverse generic variance method where adjusted odds ratios (aORs) from individual studies were combined.

MAIN RESULTS

A total of 18 new studies were included, along with the 22 studies from the 2013 review. Previously observed increased risks remained for perinatal mortality (relative risk [RR] 1.14, 95% confidence interval [CI]: 1.05, 1.23 n = 16 studies; aOR 1.07, 95% CI: 0.98-1.17 n = 6), congenital malformations (RR 1.36, 95% CI: 1.32-1.40 n = 17; aOR 1.42, 95% CI: 1.38-1.47 n = 6), and neonatal hospitalization (RR 1.27, 95% CI: 1.25-1.30 n = 12; aOR 1.1, 95% CI: 1.07-1.16 n = 3) amongst infants born to mothers with asthma, while the risk for neonatal death was no longer significant (RR 1.33, 95% CI: 0.95-1.84 n = 8). Previously reported non-significant risks for major congenital malformations (RR1.18, 95% CI: 1.15-1.21; aOR 1.20, 95% CI: 1.15-1.26 n = 3) and respiratory distress syndrome (RR 1.25, 95% CI: 1.17-1.34 n = 4; aOR 1.09, 95% CI: 1.01-1.18 n = 2) reached statistical significance.

CONCLUSIONS

Healthcare professionals should remain aware of the increased risks to neonates being born to mothers with asthma.

Effect of maternal asthma on fetal pulmonary artery Doppler parameters: a case-control study

OBJECTIVES

To compare fetal pulmonary artery Doppler parameters between pregnant women with asthma and healthy pregnant women.

METHODS

This prospective, cross-sectional study was conducted on 50 pregnant women diagnosed with asthma and 61 healthy pregnant women. Fetal pulmonary artery Doppler parameters and the fetal main pulmonary artery acceleration time/ejection time (PATET) ratio were compared between the study and control groups. Thereafter, the study group was divided into two subgroups as non-severe and severe asthma. PATET ratio was compared between the subgroups.

RESULTS

The fetal main pulmonary artery acceleration time was 25 ms in pregnant women with asthma and 33 ms in the healthy group, indicating a statistically significant difference (p=0.001). The acceleration time/ejection time ratio was statistically lower in the asthma group (0.185 vs. 0.240, p<0.001). The acceleration time/ejection time ratio was 0.172 in patients with severe asthma and 0.195 ms in the non-severe study group (p=0.156). In the maternal asthma group, the PATET ratio of those who went to the NICU due to respiratory distress was also 0.188, and the PATET ratio of those who went to the NICU for other reasons was 0.269 (p=0.053).

CONCLUSIONS

Fetal pulmonary artery acceleration time and PATET decreased statistically in pregnant women with severe or non-severe asthma. Maternal asthma is associated with changes in pulmonary Doppler parameters in the fetus.

Associations between antenatal maternal asthma status and placental DNA methylation

INTRODUCTION

Maternal asthma in pregnancy is associated with adverse perinatal and child health outcomes; however, mechanisms are poorly understood.

METHODS

The PRogramming of Intergenerational Stress Mechanisms (PRISM) prospective pregnancy cohort characterized asthma history during pregnancy via questionnaires and quantified placental DNAm using the Illumina Infinium HumanMethylation450 BeadChip. We performed epigenome-wide association analyses (n = 223) to estimate associations between maternal active or inactive asthma, as compared to never asthma, and placental differentially methylated positions (DMPs) and differentially variable positions (DVPs). Models adjusted for maternal pre-pregnancy body mass index, smoking status, parity, age and education level and child sex. P-values were FDR-adjusted.

RESULTS

One hundred and fifty-nine (71.3%) pregnant women reported no history of asthma (never asthma), 15 (6.7%) reported inactive, and 49 (22%) reported active antenatal asthma. Women predominantly self-identified as Black/Hispanic Black [88 (39.5%)] and Hispanic/non-Black [42 (18.8%)]. We identified 10 probes at FDR<0.05 and 4 probes at FDR<0.10 characterized by higher variability in maternal active asthma compared to never asthma mapping to GPX3, LHPP, PECAM1, ATAD3C, and ARHGEF4 and 2 probes characterized by lower variation mapping to CHMP4A and C5orf24. Amongst women with inactive asthma, we identified 52 probes, 41 at FDR<0.05 and an additional 11 at FDR <0.10, with higher variability compared to never asthma; BMP4, LHPP, PHYHIPL, and ZSCAN23 were associated with multiple DVPs. No associations were observed with DMPs.

DISCUSSION

We observed alterations in placental DNAm in women with antenatal asthma, as compared to women without a history of asthma. Further research is needed to understand the impact on fetal development.

Placental hypoxia: What have we learnt from small animal models?

Intrauterine hypoxia is a feature of pregnancy complications, both at high altitude and sea level. To understand the placental response to reduced oxygen availability, small animal models of maternal inhalation hypoxia (MIH) or reduced uterine perfusion pressure (RUPP) may be utilised. The aim of this review was to compare the findings of those studies to identify the role of oxygen availability in adapting placental structural and functional phenotypes in relation to fetal outcome. It also sought to explore the evidence for the involvement of particular genes and protein signalling pathways in the placenta in mediating hypoxia driven alterations. The data available demonstrate that both MIH and RUPP can induce placental hypoxia, which affects placental structure and vascularity, as well as glucose, amino acid, calcium and possibly lipid transport capacity. In addition, changes have been observed in HIF, VEGF, insulin/IGF2, AMPK, mTOR, PI3K and PPARγ signalling, which may be key in linking together observed phenotypes under conditions of placental hypoxia. Many different manipulations have been examined, with varied outcomes depending on the intensity, timing and duration of the insult. Some manipulations have detrimental effects on placental phenotype, viability and fetal growth, whereas in others, the placenta appears to adapt to uphold fetal growth despite the challenge of low oxygen. Together these data suggest a complex response of the placenta to reduced oxygen availability, which links to changes in fetal outcomes. However, further work is required to explore the role of fetal sex, altered maternal physiology and placental molecular mechanisms to fully understand placental responses to hypoxia and their relevance for pregnancy outcome.

Maternal asthma and early fetal growth, the MAESTRO study

BACKGROUND

Several maternal conditions can affect fetal growth, and asthma during pregnancy is known to be associated with lower birth weight and shorter gestational age.

OBJECTIVE

In a new Swedish cohort study on maternal asthma exposure and stress during pregnancy (MAESTRO), we have assessed if there is evidence of early fetal growth restriction in asthmatic women or if a growth restriction might come later during pregnancy.

METHODS

We recruited women from eight antenatal clinics in Stockholm, Sweden. Questionnaires on background factors, asthma status and stress were assessed during pregnancy. The participants were asked to consent to collection of medical records including ultrasound measures during pregnancy, and linkage to national health registers. In women with and without asthma, we studied reduced or increased growth by comparing the second-trimester ultrasound with first-trimester estimation. We defined reduced growth as estimated days below the 10th percentile and increased growth as days above the 90th percentile. At birth, the weight and length of the newborn and the gestational age was compared between women with and without asthma.

RESULTS

We enrolled 1693 participants in early pregnancy and collected data on deliveries and ultrasound scans in 1580 pregnancies, of which 18% of the mothers had asthma. No statistically significant reduced or increased growth between different measurement points were found when women with and without asthma were compared; adjusted odds ratios for reduced growth between first and second trimester 1.11 95% CI (0.63-1.95) and increased growth 1.09 95% CI (0.68-1.77).

CONCLUSION AND CLINICAL RELEVANCE

In conclusion, we could not find evidence supporting an influence of maternal asthma on early fetal growth in the present cohort: Although the relatively small sample size, which may enhance the risk of a type II error, it is concluded that a potential difference is likely to be very small.

From Maternal Diet to Neurodevelopmental Disorders: A Story of Neuroinflammation

Providing the appropriate quantity and quality of food needed for both the mother's well-being and the healthy development of the offspring is crucial during pregnancy. However, the macro- and micronutrient intake also impacts the body's regulatory supersystems of the mother, such as the immune, endocrine, and nervous systems, which ultimately influence the overall development of the offspring. Of particular importance is the association between unhealthy maternal diet and neurodevelopmental disorders in the offspring. Epidemiological studies have linked neurodevelopmental disorders like autism spectrum disorders, attention-deficit-hyperactivity disorder, and schizophrenia, to maternal immune activation (MIA) during gestation. While the deleterious consequences of diet-induced MIA on offspring neurodevelopment are increasingly revealed, neuroinflammation is emerging as a key underlying mechanism. In this review, we compile the evidence available on how the mother and offspring are both impacted by maternal dietary imbalance. We specifically explore the various inflammatory and anti-inflammatory effects of dietary components and discuss how changes in inflammatory status can prime the offspring brain development toward neurodevelopmental disorders. Lastly, we discuss research evidence on the mechanisms that sustain the relationship between maternal dietary imbalance and offspring brain development, involving altered neuroinflammatory status in the offspring, as well as genetic to cellular programming notably of microglia, and the evidence that the gut microbiome may act as a key mediator.

Alterations to Placental Glucocorticoid Receptor Expression with Alcohol Consumption

Maternal alcohol consumption during pregnancy results in elevated vulnerability to intrauterine growth restriction, preterm birth, miscarriage, and stillbirth. Many of the detrimental effects of fetal alcohol exposure may be mediated through placental dysfunction; however, the exact mechanisms remain unknown. Here, we aimed to determine the effect of maternal alcohol exposure prior to and during early pregnancy on placental glucocorticoid receptor (GR) isoforms, associated GR regulated genes, and infant outcomes. Participants carrying singleton fetuses (n = 113) were recruited during early pregnancy. Amount and type of alcohol consumed over the last 12 months were obtained at 18 weeks of gestation. The level of drinking was separated into none (0 g/day), low (< 10 g/day), moderate (10-100 g/day), and heavy (> 100 g/day). At delivery, placental weight, infant sex, birthweight, and head circumference were recorded. Placental GR isoforms and genes involved in downstream signalling pathways were quantified. The majority of women (70.8%) consumed alcohol. Of these, most consumed low (48.8%) or moderate (37.5%) amounts. Placental weight was unaffected by alcohol consumption, but infants born to heavy drinkers tended to be lighter at birth. In female, but not male, placentae, maternal alcohol consumption resulted in increased GRαC and decreased GRαD1 cytoplasmic expression. In both female and male placentae, a dampened inflammatory response was evident with maternal alcohol consumption, involving downregulated IL6R and upregulated POU2F2 gene expression, respectively. Maternal alcohol consumption in the months prior to, and/or during early, pregnancy alters placental GR isoform and expression of some inflammatory genes in a sex-specific manner.

Effect of maternal asthma exacerbations on perinatal outcomes: a population-based study

Background

Although there is a growing body of literature about the impact of asthma exacerbations during pregnancy on adverse perinatal outcomes, it is still unclear whether asthma exacerbations themselves or asthma severity are the driving factor for negative outcomes. This study aimed to estimate the associations between maternal asthma exacerbations and perinatal outcomes, and whether this differed by asthma treatment regime as a proxy for severity.

Methods

We included births of women with asthma in Sweden from July 2006 to November 2013 (n=33 829). Asthma exacerbations were defined as unplanned emergency visits/hospitalisations or a short course of oral corticosteroids. Adjusted odds ratios (aOR) were estimated for the associations between exacerbations during pregnancy and perinatal outcomes (small for gestational age (SGA), preterm birth, birthweight and mode of delivery), stratified by preconception treatment regime.

Results

Exacerbations occurred in 1430 (4.2%) pregnancies. Exacerbations were associated with reduced birthweight (aOR 1.45, 95% CI 1.24–1.70), and elective (aOR 1.50, 95% CI 1.25–1.79) and emergency caesarean section (aOR 1.35, 95% CI 1.13–1.61). Multiple exacerbations were associated with a 2.6-fold increased odds of SGA (95% CI 1.38–4.82). Amongst women treated prepregnancy with combination therapy (proxy for moderate–severe asthma), exacerbators were at increased odds of elective (aOR 1.69, 95% CI 1.30–2.2) and emergency (aOR 1.62, 95% CI 1.26–2.08) caesarean section, and SGA (aOR 1.74, 95% CI 1.18–2.57) versus non-exacerbators.

Conclusion

Maternal asthma exacerbations increase the risk of SGA and caesarean sections, particularly in women with multiple exacerbations or moderate–severe asthma. Adequate antenatal asthma care is needed to reduce exacerbations and reduce risks of poor outcomes.

Maternal asthma exacerbations are associated with lower birthweight and increased caesarean sections, particularly in women with moderate–severe asthma. Adequate antenatal asthma care is needed to reduce exacerbations and reduce risks of poor outcomes.https://bit.ly/3kF4x8N

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

INTRODUCTION

Asthma is a highly prevalent co-morbidity during pregnancy that can worsen as gestation progresses and is associated with several adverse perinatal outcomes. These adverse outcomes often result from uncontrolled asthma during pregnancy and acute asthma exacerbations that are associated with alterations in placental function and fetal growth.

AREAS COVERED

This paper will discuss how maternal asthma in pregnancy affects fetal growth and development which may alter future offspring health. Changes in placental function occur in a sex-specific manner in pregnancies complicated by asthma and result in differences in fetal growth and development which may influence child health. The follow up of children from mothers with asthma suggests they are at greater risk of developing asthma, have alterations in microvascular structure that may contribute to a future risk of cardiovascular disease and epigenetic modifications in immune cell function. The current evidence suggests that appropriately managed asthma during pregnancy results in normal fetal growth and development.

EXPERT OPINION

Clinical management of asthma during pregnancy needs significant improvement to prevent adverse outcomes for the fetus. The key to improving maternal and fetal outcomes is through education of health professionals and parents about controlling asthma during pregnancy.

Findings in Stillbirths Associated with Placental Disease

OBJECTIVE

Placental disease is a leading cause of stillbirth. Our purpose was to characterize stillbirths associated with placental disease.

STUDY DESIGN

The Stillbirth Collaborative Research Network conducted a prospective, case-control study of stillbirths and live births from 2006 to 2008. This analysis includes 512 stillbirths with cause of death assignment and a comparison group of live births. We compared exposures between women with stillbirth due to placental disease and those due to other causes as well as between women with term (≥ 37 weeks) stillbirth due to placental disease and term live births.

RESULTS

A total of 121 (23.6%) out of 512 stillbirths had a probable or possible cause of death due to placental disease by Initial Causes of Fetal Death. Characteristics were similar between stillbirths due to placental disease and other stillbirths. When comparing term live births to stillbirths due to placental disease, women with non-Hispanic black race, Hispanic ethnicity, lack of insurance, or who were born outside of the United States had higher odds of stillbirth due to placental disease. Nulliparity and antenatal bleeding also increased risk of stillbirth due to placental disease.

CONCLUSION

Multiple discrete exposures were associated with stillbirth caused by placental disease. The relationship between these factors and utility of surveillance warrants further study.

The impact of maternal asthma during pregnancy on offspring retinal microvascular structure and its relationship to placental growth factor production in utero

Asthma is a common chronic disease in pregnancy that affects placental function and fetal growth and associated with cardio-metabolic disorders in the offspring but the mechanisms are unknown. This study explored whether maternal asthma in pregnancy is associated with the development of offspring microvascular structure and whether it was related to biomarkers of angiogenesis in utero. Children aged 4 to 6 years, born to either asthmatic mothers (n = 38) or healthy controls (n = 25), had their retinal microvascular structure examined. Maternal plasma PlGF concentrations at 18 and 36 weeks' gestation were measured. There was a significant global difference in all retinal microvascular measures between children of asthmatic mothers relative to controls and increased retinal venular tortuosity in children born to asthmatic mothers (7.1 (95% CI 0.7-13.5); P = .031). A rise in plasma PlGF from 18 to 36 weeks' gestation was observed in the control population which was significantly lower in the asthma group by 190.9 pg/mL. PlGF concentrations were correlated with microvascular structure including arteriolar branching and venular tortuosity. These exploratory findings indicate that exposure to maternal asthma during pregnancy is associated with persistent changes in microvascular structure in childhood that may be driven by alterations to angiogenic mechanisms in utero.

Effect of asthma exacerbation during pregnancy in women with asthma: a population-based cohort study

The association between asthma exacerbation during pregnancy and adverse maternal and child health outcomes have not been investigated appropriately. Our objective was to determine the short- and long-term intergenerational effect of asthma exacerbation in pregnant women with asthma.A population cohort study was conducted using data from the Ontario asthma surveillance system and population-level health administrative data. Asthma exacerbation in pregnant women with asthma was defined as at least one of the following criteria: at least five physician visits, or one emergency department visit or one hospital admission for asthma during pregnancy. Pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders were identified using International Classification of Disease codes (9th and 10th revisions).The cohort consisted of 103 424 singleton pregnancies in women with asthma. Asthma exacerbation in pregnant women with asthma was associated with higher odds of pre-eclampsia (OR 1.30, 95% CI 1.12-1.51) and pregnancy-induced hypertension (OR 1.17, 95% CI 1.02-1.33); babies had higher odds of low birthweight (OR 1.14, 95% CI 1.00-1.31), preterm birth (OR 1.14, 95% CI 1.01-1.29) and congenital malformations (OR 1.21, 95% CI 1.05-1.39). Children born to women with asthma exacerbation during pregnancy had elevated risk of asthma (OR 1.23, 95% CI 1.13-1.33) and pneumonia (OR 1.12, 95% CI 1.03-1.22) during the first 5 years of life.Asthma exacerbation during pregnancy in women with asthma showed increased risk of pregnancy complications, adverse perinatal outcomes and early childhood respiratory disorders in their children, indicating that appropriate asthma management may reduce the risk of adverse health outcomes.

Asthma knowledge, care, and outcome during pregnancy: The QAKCOP study

Asthma is the most common chronic medical condition affecting pregnancy. Optimizing asthma management in pregnancy is paramount for the well-being of both the mother and the baby. The primary objectives of this study were to assess patient’s knowledge about asthma, the level of asthma care, and fetal and maternal outcomes among pregnant asthmatic women in this wealthy country with tremendous improvement in maternal and fetal health care. The secondary objective was to identify barriers to asthma control. This was a cross-sectional, face-to-face, prospective study of 80 pregnant women with physician-diagnosed asthma. About 56% of patients reported worsening of their asthma control during pregnancy, of which 52.3% felt this worsening in the third trimester. About 65% of patients had uncontrolled asthma during their pregnancy, and inhaler technique was incorrect in 64.4%. Only 38% of patients knew the difference between controller and reliever asthma medications, 12.7% of patients had received written asthma action plan, 17% had a spirometry done in the previous 5 years, and 3.8% had peak expiratory flow meter at home. The main reasons for uncontrolled asthma were lack of knowledge about right asthma medications in 30% and fear of side effects of inhaled corticosteroids in 19% of patients. No financial reason was reported. Significant associations between total number of pregnancies, poor perception of asthma medications, asthma exacerbation during delivery and poor asthma control were observed. Preeclampsia and congenital anomalies occurred at higher rates than previously reported among general population in this country. The tremendous improvements in maternal health care and socioeconomic status do not seem to be a barrier to the globally recognized poor asthma care in pregnancy. Important strategies are much needed.

Pregnancy outcomes among women with asthma

PURPOSE

The purpose of this study is to examine the association between maternal asthma and pregnancy, delivery and neonatal outcomes.

MATERIALS AND METHODS

We carried out a retrospective cohort study using the Health Care Cost and Utilization Project-Nationwide Inpatient Sample (HCUP-NIS) database from 2003 to 2011. Among women who delivered during this time period, we compared pregnancy, delivery, and neonatal outcomes in asthmatics versus non-asthmatics. Multivariate logistic regression was used to estimate adjusted odds ratios and 95% confidence intervals.

RESULTS

In a cohort of 7,772,999 pregnant women, 223,236 (2.9%) had asthma. The prevalence of asthma-complicated pregnancies rose over the study period from 1.9% in 2003 to 3.7% in 2011 (p < .001). Pregnant asthmatics had more pre-existing health conditions, such as diabetes, chronic hypertension, obesity, and thyroid disease, and were more likely to smoke. Even after adjustment for these comorbidities, and other covariates, within statistical models, asthma was found to be associated with greater risk of several pregnancy complications: gestational hypertension, preeclampsia, gestational diabetes, placenta previa, preterm premature rupture of membranes, placental abruption, chorioamnionitis, preterm delivery, postpartum hemorrhage, venous thromboembolism, caesarean section delivery, and maternal mortality. Neonates born to asthmatics had greater risk of being small for gestational age and for having congenital anomalies, and lower risk of intrauterine fetal death.

CONCLUSIONS

Asthma is associated with an increase in adverse pregnancy, labor, and neonatal outcomes. Close surveillance of asthmatic patients during the prenatal period is warranted and care in a tertiary hospital is advised.

Review: Placental adaptations to the presence of maternal asthma during pregnancy

Asthma is a highly prevalent chronic medical condition affecting an estimated 12% of pregnant, women each year, with prevalence of asthma greatest (up to 16%) among the socially disadvantaged. Maternal asthma is associated with significant perinatal morbidity and mortality including preterm births, neonatal hospitalisations and low birthweight outcomes each year. We have identified that the placenta adapts to the presence of chronic, maternal asthma during pregnancy in a sex specific manner that may confer sex differences in fetal outcome. The male fetus was at greater risk of a poor outcome than a female fetus in the presence of maternal asthma and an acute inflammatory event such as an asthma exacerbation. This review will examine the role of sex specific differences in placental function on fetal growth and survival.

Low birth weight at term and the presence of fine particulate matter and carbon monoxide in the Brazilian Amazon: a population-based retrospective cohort study

BACKGROUND

Although studies have shown an association between air pollutants from anthropogenic sources and pregnancy outcomes, little is known regarding the association between low birth weight (LBW) and exposure to emissions of biomass burning.

METHODS

This population-based retrospective cohort study assessed the effect of exposure to particulate matter and carbon monoxide (CO) from biomass burning in the Amazon and cerrado (Brazilian savanna) biomes on term LBW (<2500 g) in cities of Mato Grosso, Brazil. Data on births were obtained from the Information System on Live Births of the Ministry of Health. The exclusion criteria were a twin pregnancy, gestational age of less than 37 weeks, and congenital malformation diagnosed at birth. For exposure variables, we used a historical series of daily average concentrations of particulate matter with a diameter less than 2.5 μm (PM2.5) and CO provided by Coupled Aerosol and Trace Gases Transport Model for the Brazilian Development of the Regional Atmospheric Modeling System developed at the National Institute for Space National Center for Weather Forecasts and Climate Studies, National Institute for Space Research. Maternal exposure was estimated by the average amount of pollutants for each trimester and for the entire period of gestation. The association between air pollutants and LBW was analyzed by multiple logistic regression, adjusting for the newborn's sex, mother's age and education, and prenatal care.

RESULTS

A total of 6147 full-term singleton live births were included in the study and 193 (3.1%) were LBW. In adjusted analysis, the number of prenatal visits and maternal education with 8 years or more were associated with LBW. The association between exposure to air pollutants and the risk of LBW was significant for the 4th quartile of PM2.5 concentrations in the 2nd trimester (OR = 1.51, 95% CI = 1.04 to 2.17) and in the 3rd trimester, and for the 4th quartile of CO concentrations in the 2nd trimester only, in adjusted analysis.

CONCLUSIONS

This study provides further evidence of the effect of smoke from biomass burning on the occurrence of LBW in cities of the Brazilian Amazon.

The risk of maternal and placental complications in pregnant women with asthma: a systematic review and meta-analysis

OBJECTIVE

To investigate if maternal asthma is associated with an increased risk of maternal and placental complications in pregnancy.

METHODS

Electronic databases were searched for the following terms: (asthma or wheeze) and (pregnan* or perinat* or obstet*). Cohort studies published between January 1975 and March 2012 were considered for inclusion. Forty publications met the inclusion criteria, reporting at least one maternal or placental complication in pregnant women with and without asthma. Relative risk (RR) with 95% confidence intervals (CIs) was calculated.

RESULTS

Maternal asthma was associated with a significantly increased risk of cesarean section (RR = 1.31, 95%CI = [1.22-1.39]), gestational diabetes (RR = 1.39, 95%CI = [1.17-1.66]), hemorrhage (antepartum: RR = 1.25, 95%CI = [1.10-1.42]; postpartum: RR = 1.29, 95%CI = [1.18-1.41]), placenta previa (RR = 1.23, 95%CI = [1.07-1.40]), placental abruption (RR = 1.29, 95%CI = [1.14-1.47]) and premature rupture of membranes (RR = 1.21, 95%CI = 1.07-1.37). Moderate to severe asthma significantly increased the risk of cesarean section (RR = 1.19, 95%CI = [1.09-1.31]) and gestational diabetes (RR = 1.19, 95%CI = [1.06-1.33]) compared to mild asthma. Bronchodilator use was associated with a significantly lowered risk of gestational diabetes (RR = 0.64, 95%CI = [0.57-0.72]).

CONCLUSIONS

Pregnant women with asthma are at increased risk of maternal and placental complications, and women with moderate/severe asthma may be at particular risk. Further studies are required to elucidate whether adequate control of asthma during pregnancy reduces these risks.

Asthma during pregnancy and clinical outcomes in offspring: a national cohort study

BACKGROUND AND OBJECTIVE

Maternal asthma is a common pregnancy complication, with adverse short-term effects for the offspring. The objective was to determine whether asthma during pregnancy is a risk factor of offspring diseases.

METHODS

We studied pregnant women from the Danish National Birth Cohort (births: 1996-2002; prospective data) giving birth to live singletons (n = 66 712 mother-child pairs), with 4145 (6.2%) women suffering from asthma during pregnancy. We estimated the associations between asthma during pregnancy and offspring diseases (International Classification of Diseases, 10th Revision diagnoses from national registries), controlling for potential confounders and validating findings by secondary analyses.

RESULTS

Offspring median age at end of follow-up was 6.2 (3.6-8.9) years. Asthma was associated with an increased offspring risk of infectious and parasitic diseases (hazard ratio [HR] 1.34; 95% confidence interval [CI] 1.23-1.46), diseases of the nervous system (HR 1.43; CI 1.18-1.73), ear (HR 1.33; CI 1.19-1.48), respiratory system (HR 1.43; CI 1.34-1.52), and skin (HR 1.39; CI 1.20-1.60), and potentially (not confirmed in secondary analyses) of endocrine and metabolic disorders (HR 1.26; CI 1.02-1.55), diseases of the digestive system (HR 1.17; CI 1.04-1.32), and malformations (odds ratio 1.13; CI 1.01-1.26), but not of neoplasms, mental disorders, or diseases of the blood and immune system, circulatory system, musculoskeletal system, and genitourinary system.

CONCLUSIONS

To the best of our knowledge, this is the first comprehensive study of the associations between asthma during pregnancy and a wide spectrum of offspring diseases. In line with previous data on selected outcomes, asthma during pregnancy may be a risk factor for numerous offspring diseases, suggesting that careful monitoring of women with asthma during pregnancy and their offspring is important.

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.

Airborne PM2.5 chemical components and low birth weight in the northeastern and mid-Atlantic regions of the United States

BACKGROUND

Previous studies on air pollutants and birth outcomes have reported inconsistent results. Chemical components of particulate matter ≤ 2.5 µm (PM2.5) composition are spatially -heterogeneous, which might contribute to discrepancies across PM2.5 studies.

OBJECTIVES

We explored whether birth weight at term is affected by PM2.5, PM10 (PM ≤ 10 µm), and gaseous pollutants.

METHODS

We calculated exposures during gestation and each trimester for PM2.5 chemical components, PM10, PM2.5, carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide for births in 2000-2007 for states in the northeastern and mid-Atlantic United States. Associations between exposures and risk of low birth weight (LBW) were adjusted by family and individual characteristics and region. Interaction terms were used to investigate whether risk differs by race or sex.

RESULTS

Several PM2.5 chemical components were associated with LBW. Risk increased 4.9% (95% CI: 3.4, 6.5%), 4.7% (3.2, 6.2%), 5.7% (2.7, 8.8%), and 5.0% (3.1, 7.0%) per interquartile range increase of PM2.5 aluminum, elemental carbon, nickel, and titanium, respectively. Other PM2.5 chemical components and gaseous pollutants showed associations, but were not statistically significant in multipollutant models. The trimester associated with the highest relative risk differed among pollutants. Effect estimates for PM2.5 elemental carbon and nickel were higher for infants of white mothers than for those of African-American mothers, and for males than females.

CONCLUSIONS

Most exposure levels in our study area were in compliance with U.S. Environmental Protection Agency air pollution standards; however, we identified associations between PM2.5 components and LBW. Findings suggest that some PM2.5 components may be more harmful than others, and that some groups may be particularly susceptible.

Management of asthma during pregnancy

Asthma is an inflammatory lung condition that is the most common chronic disease affecting pregnancy. The changes in pulmonary physiology during pregnancy include increased minute ventilation, decreased functional residual capacity, increased mucus production, and airway mucosa hyperemia and edema. Pregnancy is also associated with a physiological suppression of the immune system. Many studies have described the heterogeneous immune system response in women with asthma during pregnancy, which partly explains why asthma has been shown to worsen, improve, or remain stable in equal proportions of women during pregnancy. Asthma may be associated with poor maternal and fetal outcomes. However, better maternal and fetal outcomes are observed with better asthma control. Asthma controller medications are generally thought to be safe during pregnancy, but limited data are available for some of the medicines. Newer medications like omalizumab open avenues for the treatment of asthma, but also pose a challenge, as there is limited experience with their use. Therefore, a multidisciplinary approach, including obstetricians, asthma specialists, and pediatricians should collaborate with the patient to carefully weigh the risks and benefits to determine an optimal management plan for each individual patient. The aim of this review article is to summarize the most recent literature about the immunological changes that occur during pregnancy, physiological and clinical implications of asthma on pregnancy, and asthma management and medication use in pregnant women.

Distinctive bronchial inflammation status in athletes: basophils, a new player

The aim of the study was to establish bronchial inflammation status and to measure eicosanoids in sputum obtained from active elite athletes. A total of 68 subjects were enrolled. Twelve were non-athletes and non-asthmatic (NAtNAs), 21 non-athlete asthmatics (NAtAs), 11 athlete non-asthmatics (AtNAs), and 24 athletes with asthma (AtAs) with positive indirect or direct bronchial challenges. Induced sputum was used to measure cells and eicosanoids. Sputum differential cell counts in all the subject groups revealed eosinophilia with the exception of NAtNAs control subjects. Athletes with and without diagnosed asthma showed a significant increase in bronchial epithelial cells and lymphocytes present in their sputum. Also, flow cytometry revealed that a significantly higher number of basophils were present in sputum from athletes (without and with asthma) when compared with non-athletes (without and with asthma). Asthmatic athletes and non-athletes showed a higher increase in LTC(4) levels and PGE(2) metabolites in sputum when compared with healthy controls. The present study identifies basophils as a new player present in athletes bronchial inflammation defining athlete status and not necessarily associated with exercise-induced bronchoconstriction.

Developmental perturbation induced by maternal asthma during pregnancy: the short- and long-term impacts on offspring

Maternal asthma is a common disease to complicate human pregnancy. Epidemiological studies have identified that asthma during pregnancy increases the risk of a number of poor outcomes for the neonate including growth restriction, lower birthweight, preterm delivery, neonatal resuscitation, and stillbirth. Asthma therefore represents a significant health burden to society and could have an impact on the lifelong health of the children of women with asthma. Our research has identified that maternal asthma in pregnancy induces placental dysfunction and developmental perturbation in the fetus in a sex specific manner. These alterations in development could increase the risk of metabolic disease in adulthood of children of asthmatic mothers, especially females. In this paper, we will discuss the evidence currently available that supports the hypothesis that children of mothers with asthma may be at risk of lifelong health complications which include diabetes and hypertension.

Perinatal complications associated with maternal asthma during pregnancy

BACKGROUND

Asthma is one of the most common medical illnesses occurring in pregnancy and its incidence amongst the obstetric population is increasing. Previous studies have suggested that asthma is not a benign illness in pregnancy, and can contribute towards increased rates of pregnancy complications.

METHODS

We undertook a retrospective audit of 6458 deliveries during 2008 at The Royal Women's Hospital to determine the perinatal outcomes for women with a self-reported diagnosis of asthma.

RESULTS

We found that 501 (7.8%) deliveries were to women who identified themselves as asthmatics. Of these, 15.6% reported exacerbations of their asthma symptoms during pregnancy, with the remainder reporting improvement or stabilization. There was an increased rate of preterm birth (12.9%) in the asthmatic population, compared to the non-asthmatic population (OR = 1.48, CI [1.12-1.95], P = 0.005). Asthma remained significantly associated with an increased risk of preterm birth after adjusting for maternal smoking status using logistic regression analysis (Adjusted OR 1.41, CI [1.07-1.86], P = 0.01). Women were also at increased risk of developing pre-eclampsia (OR 1.71, CI [1.09-2.67], P = 0.02) but not fetal growth restriction. Women identifying themselves as asthmatics were also more likely to deliver by caesarean section (OR 1.32, CI [1.09-1.6], P = 0.003).

CONCLUSION

These findings suggest that maternal asthma may be associated with an increased risk of preterm birth, pre-eclampsia and caesarean delivery.

A meta-analysis of adverse perinatal outcomes in women with asthma

BACKGROUND

Asthma is a common condition during pregnancy and may be associated with adverse perinatal outcomes.

OBJECTIVE

This meta-analysis sought to establish if maternal asthma is associated with an increased risk of adverse perinatal outcomes, and to determine the size of these effects.

SEARCH STRATEGY

Electronic databases were searched for the following terms: (asthma or wheeze) and (pregnan* or perinat* or obstet*).

SELECTION CRITERIA

Cohort studies published between 1975 and March 2009 were considered for inclusion. Studies were included if they reported at least one perinatal outcome in pregnant women with and without asthma.

DATA COLLECTION AND ANALYSIS

A total of 103 articles were identified, and of these 40 publications involving 1,637,180 subjects were included. Meta-analysis was conducted with subgroup analyses by study design and active asthma management.

MAIN RESULTS

Maternal asthma was associated with an increased risk of low birthweight (RR 1.46, 95% CI 1.22-1.75), small for gestational age (RR 1.22, 95% CI 1.14-1.31), preterm delivery (RR 1.41, 95% CI 1.22-1.61) and pre-eclampsia (RR 1.54, 95% CI 1.32-1.81). The relative risk of preterm delivery and preterm labour were reduced to non-significant levels by active asthma management (RR 1.07, 95% CI 0.91-1.26 for preterm delivery; RR 0.96, 95% CI 0.73-1.26 for preterm labour).

AUTHOR'S CONCLUSIONS

Pregnant women with asthma are at increased risk of perinatal complications, including pre-eclampsia and outcomes that affect the baby's size and timing of birth. Active asthma management with a view to reducing the exacerbation rate may be clinically useful in reducing the risk of perinatal complications, particularly preterm delivery.

Maternal allergy acts synergistically with cigarette smoke exposure during pregnancy to induce hepatic fibrosis in adult male offspring

Maternal environmental exposures during pregnancy are known to affect disease onset in adult offspring. For example, maternal asthma exacerbations during pregnancy can worsen adult asthma in the offspring. Cigarette smoking during pregnancy is associated with future onset of cardiovascular disease, obesity and diabetes. However, little is known about the effect of maternal environmental exposures on offspring susceptibility to liver disease. This pilot study examined the long-term effect of maternal allergen challenge and/or cigarette smoking during pregnancy on hepatic inflammation and fibrosis in adult mouse offspring. Ovalbumin (OVA) or phosphate-buffered saline (PBS)-sensitized/challenged CD-1 dams were exposed to mainstream cigarette smoke (MCS) or filtered air from gestational day 4 until parturition. Eight weeks postnatally, offspring were sacrificed for comparison of hepatic histology and mRNA expression. Adult male offspring of OVA-sensitized/challenged dams exposed to MCS (OSM) displayed significantly increased liver fibrosis (9.2% collagen content vs. <4% for all other treatment groups). These mice also had 1.8-fold greater collagen 1A1 mRNA levels. From the results here, we concluded that maternal allergen challenge in combination with cigarette smoke exposure during pregnancy may be an important risk factor for liver disease in adult male offspring.

Asthma, asthma medications and their effects on maternal/fetal outcomes during pregnancy

Maternal asthma may increase the risk of adverse fetal and maternal outcomes such as low birth weight, perinatal mortality, preterm birth, preeclampsia, hypertensive disorders, maternal mortality, uterine hemorrhage, and gestational diabetes. Controlling asthma during pregnancy with appropriate medications leads to improved intrauterine growth of the fetus and fewer adverse perinatal outcomes. Prospective population or birth cohort studies have shown that the medications used to treat asthma, such as bronchodilators (short-acting β2-agonists) and controller medications (inhaled corticosteroids, cromones, theophylline, leukotriene inhibitors), have no or minimal effects on fetal growth, and perinatal complications are reduced when maternal asthma is adequately controlled. However, taking oral corticosteroids during pregnancy may confer increased risk of lower birth weight and congenital malformations. Therefore, managing pregnant asthmatics requires a careful benefit-risk analysis, and when indicated, the benefits of a medication that may have increased risks can dictate its use in severe uncontrolled asthma.

The presence of maternal asthma during pregnancy suppresses the placental pro-inflammatory response to an immune challenge in vitro

The mechanisms that contribute to adverse outcomes for the neonate in pregnancies complicated by asthma may be mediated via changes in placental immune function. This study was designed to determine whether the presence of maternal asthma during pregnancy alters the placental pro-inflammatory immune response in vitro. A prospective cohort study of women with asthma (n = 22) and control (n = 11) subjects had placentae collected immediately after delivery. Placental explants were exposed to an immune challenge, lipopolysaccharide, in the presence and absence of cortisol in vitro. Cytokines, glucocorticoid receptor α (GR α) and p38 MAPK protein were measured. Placentae of control pregnancies had an increase in pro-inflammatory cytokine production over a 24 h period. Placentae from pregnancies complicated by maternal asthma had a reduced pro-inflammatory cytokine response to an immune challenge relative to the controls especially in relation to the production of interleukin (IL)-1β and TNFα regardless of fetal sex. Cortisol inhibition of placental cytokine production was dependent on timing of exposure, fetal sex and presence and absence of asthma. GRα and p38 MAPK protein expression did not appear to contribute to differences in response to endotoxin or cortisol. Maternal asthma during pregnancy induces a hyposensitive inflammatory state in the placenta which is regulated by cortisol in a sexually dimorphic manner.

Asthma in pregnancy

Worldwide the prevalence of asthma among pregnant women is on the rise, and pregnancy leads to a worsening of asthma for many women. This article examines the changes in asthma that may occur during pregnancy, with particular reference to asthma exacerbations. Asthma affects not only the mother but the baby as well, with potential complications including low birth weight, preterm delivery, perinatal mortality, and preeclampsia. Barriers to effective asthma management and opportunities for optimized care and treatment are discussed, and a summary of the clinical guidelines for the management of asthma during pregnancy is presented.

Air pollution toxicology--a brief review of the role of the science in shaping the current understanding of air pollution health risks

Human and animal toxicology has had a profound impact on our historical and current understanding of air pollution health effects. Early animal toxicological studies of air pollution had distinctively military or workplace themes. With the discovery that ambient air pollution episodes led to excess illness and death, there became an emergence of toxicological studies that focused on industrial air pollution encountered by the general public. Not only did the pollutants investigated evolve from ambient mixtures to individual pollutants but also the endpoints and outcomes evaluated became more sophisticated, resulting in our present state of the science. Currently, a large toxicological database exists for the effects of particulate matter and ozone, and we provide a focused review of some of the major contributions to the biological understanding for these two "criteria" air pollutants. A limited discussion of the toxicological advancements in the scientific knowledge of two hazardous air pollutants, formaldehyde and phosgene, is also included. Moving forward, the future challenge of air pollution toxicology lies in the health assessment of complex mixtures and their interactions, given the projected impacts of climate change and altered emissions on ambient conditions. In the coming years, the toxicologist will need to be flexible and forward thinking in order to dissect the complexity of the biological system itself, as well as that of air pollution in all its varied forms.

Effect of maternal asthma, inhaled glucocorticoids and cigarette use during pregnancy on the newborn insulin-like growth factor axis

BACKGROUND

Fetal growth varies in a sex-specific manner in response to maternal asthma during pregnancy, but the mechanisms are unclear.

OBJECTIVE

We examined the influence of maternal asthma severity and associated exposures, inhaled glucocorticoid treatment, maternal cigarette use, and fetal sex on fetal growth and placental function during pregnancy and on the newborn insulin-like growth factor (IGF) axis. STUDY SUBJECTS AND DESIGN: Fetal growth was assessed in a prospective cohort of asthmatic and non-asthmatic women (n=145). At delivery, umbilical vein plasma was collected from male (n=61, controls n=16 and asthmatic n=45) or female (n=84, controls n=22 and asthmatic n=62) fetuses. Cord plasma insulin-like growth factor (IGF) binding protein (BP)-1, IGFBP-3, IGF-1 and IGF-2 were measured by radioimmunoassay and ELISA.

RESULTS

Cord plasma IGF-1 was the main component of the neonatal IGF axis altered by asthma and cigarette use. IGF-1 was increased in the presence of mild asthma and a male fetus and decreased in the presence of a female fetus and maternal asthma with cigarette use. IGFBP-3 was also decreased in the female fetuses of pregnancies complicated by asthma and cigarette use. Inhaled glucocorticoid use for the treatment of asthma did not affect the IGF axis. The strongest overall predictor of female birth weight after accounting for asthma severity, inhaled glucocorticoid treatment and cigarette use was IGF-1. For males, the strongest predictor of birth weight was IGFBP-3.

CONCLUSION

The data suggest male and female fetuses institute different strategies in response to adverse pregnancy conditions such as asthma and cigarette use.

Changes in human placental 5alpha-reductase isoenzyme expression with advancing gestation: effects of fetal sex and glucocorticoid exposure

5alpha-reduced steroids, including allopregnanolone, suppress neuronal activity and can have neuroprotective effects in the fetus. 5alpha-reductases in the placenta may contribute precursors to brain allopregnanolone synthesis. Preterm birth and glucocorticoids, administered for fetal lung maturation or for maternal asthma, may influence reductase expression. The aims of the present study were to evaluate placental 5alpha-reductase isoform expression during late gestation and to examine fetal sex differences and the effects of glucocorticoid therapies on the expression of these enzymes. Expression of the two 5alpha-reductase isoenzymes was measured in placental samples, whereas cortisol concentrations were measured in cord blood, from two cohorts. The first cohort consisted of women who delivered preterm and received betamethasone treatment (n=41); the second cohort consisted of women who delivered at term and were either healthy controls (n=30) or asthmatics who had used glucocorticoids (n=24). Placental expression of both isoenzymes increased with advancing gestation and there were marked sex differences in levels of 5alpha-reductase I (P<0.05), but not of 5alpha-reductase II. The expression of both enzymes was positively correlated with cortisol levels (P<0.05), but there was no effect of recent glucocorticoid exposure. These findings suggest that the preterm neonate may have lower developmental exposure to 5alpha-reduced steroids and may lack steroid-mediated neuroprotection depending on fetal sex.

Placental cytokine expression covaries with maternal asthma severity and fetal sex

In the presence of maternal asthma, we have previously reported reduced placental blood flow, decreased cortisol metabolism, and reductions in fetal growth in response to maternal asthma and asthma exacerbations. We have proposed that these changes in placental function and fetal development may be related to activation of proinflammatory pathways in the placenta in response to maternal asthma. In the present study, we examined the influence of maternal asthma severity, inhaled glucocorticoid treatment, maternal cigarette use, placental macrophage numbers, and fetal sex on placental cytokine mRNA expression from a prospective cohort study of pregnant women with and without asthma. Placental expression of TNF-alpha, IL-1beta, IL-6, IL-8, and IL-5 mRNA were all increased significantly in placentae of female fetuses whose mothers had mild asthma, but no changes were observed in placentae of male fetuses. The proinflammatory cytokines TNF-alpha, IL-1beta, and IL-6 were negatively correlated with female cord blood cortisol, but there were no such correlations in placentae from males. Multivariate analysis indicated the strongest predictor of both cytokine mRNA expression in the placenta and birth weight was fetal cortisol but only in females. Placental cytokine mRNA levels were not significantly altered by inhaled glucocorticoid use, placental macrophage numbers, cigarette use, moderate-severe asthma, or male sex. These data suggest that placental basal cytokine mRNA expression is sex specifically regulated in pregnancies complicated by asthma, and interestingly these changes are more prevalent in mild rather than severe asthma.

Maternal asthma and placental morphometry: effects of severity, treatment and fetal sex

Asthma is the most common respiratory disease to complicate pregnancy. Although adverse effects on the fetus have been documented, there is a paucity of information regarding the effects of asthma, and its treatment, on placental morphology. The aim of this study was to test for volumetric differences in placental composition between non-asthmatic pregnancies and those associated with maternal asthma grouped according to asthma severity and glucocorticoid (GC) treatment. Each placenta was weighed and random samples of tissue were fixed in formalin-saline, embedded in wax and analysed by design-based stereology. Volume densities of parenchymal compartments (peripheral villi and maternal intervillous space) and residual non-parenchyma were estimated by test point counting and converted to absolute volumes by taking into account placental size. Relative and absolute lengths of villi and capillaries were also estimated and used to derive secondary quantities related to villous capillarization and maturation. Between-group comparisons were drawn by two-way analysis of variance with group and fetal sex as the principal factors. Compared to non-asthmatic controls, asthmatics had reduced absolute volumes of fetal capillaries which was most marked in those with moderate/severe asthma and those using low and high doses of inhaled GCs. Changes in the total length and mean cross-sectional area of capillaries and peripheral villi were also observed. Lengths were greater in mild asthmatics and lowest in those with high GC usage. Calibre areas were lower in mild asthmatics and villous calibres in the high GC group were greater than those in asthmatics not taking GCs. Those making greatest use of inhaled GCs also had villi which were hypovascularized in terms of capillary:villus length ratios. The findings suggest that the morphometric differences in fetoplacental vascularity are likely to be due to the effects of asthma and use of inhaled GCs rather than the effects of maternal or fetal hypoxic stress.

The effect of a mast cell degranulating agent on vascular resistance in the human placental vascular bed and on the tone of isolated placental vessels

The objective of this study is to investigate the effect of a mast cell degranulating agent, compound 48/80, on vascular resistance in the perfused human placenta and on the tone of isolated human chorionic vessels. Human placenta was obtained from term nonlaboring women undergoing cesarean delivery. Placental vascular bed perfusion pressure and isometric tension for segments of chorionic plate artery and vein were obtained in response to potassium chloride, compound 48/80, a mast cell stabilizer (cromolyn), and thromboxane A2 mimetic (U46619). Compound 48/80 significantly increased perfusion pressure in isolated human placental cotyledons. This effect was significantly potentiated further after induction of active vascular tone by thromboxane A2 mimetic U46619. Cromolyn significantly attenuated responses to compound 48/80 in these preparations. Compound 48/80 also significantly increased tone in isolated human chorionic artery and vein rings, and responses were abolished by cromolyn. In conclusion, degranulation of placental and intravascular mast cells by compound 48/80 leads to the release of vasoconstrictive substances. This could impair placental blood flow and result in growth restriction in fetuses of women with type l hypersensitivity reactions.

A stereological perspective on placental morphology in normal and complicated pregnancies

Stereology applied to randomly-generated thin sections allows minimally-biased and economical quantitation of the 3D structure of the placenta from molecular to whole-organ levels. With these sampling and estimation tools, it is possible to derive global quantities (tissue volumes, interface surface areas, tubule lengths and particle numbers), average values (e.g. mean cell size or membrane thickness), spatial relationships (e.g. between compartments and immunoprobes) and functional potential (e.g. diffusive conductance). This review indicates ways in which stereology has been used to interpret the morphology of human and murine placentas including the processes of villous growth, trophoblast differentiation, vascular morphogenesis and diffusive transport. In human placenta, global quantities have shown that villous maturation involves differential growth of fetal capillaries and increases in endothelial cell number. Villous trophoblast is a continuously renewing epithelium and, through much of gestation, exhibits a steady state between increasing numbers of nuclei in cytotrophoblast (CT) and syncytiotrophoblast (ST). The epithelium gradually becomes thinner because its surface expands at a faster rate than its volume. These changes help to ensure that placental diffusing capacity matches the growth in fetal mass. Comparable events occur in the murine placenta. Some of these processes are perturbed in complicated pregnancies: 1) fetoplacental vascular growth is compromised in pregnancies accompanied by maternal asthma, 2) changes in trophoblast turnover occur in pre-eclampsia and intrauterine growth restriction, and 3) uteroplacental vascular development is impoverished, but diffusive transport increases, in pregnant mice exposed to particulate urban air pollution. Finally, quantitative immunoelectron microscopy now permits more rigorous analysis of the spatial distributions of interesting molecules between subcellular compartments or shifts in distributions following experimental manipulation.

Effect of maternal asthma and asthma control on pregnancy and perinatal outcomes

BACKGROUND

Asthma is a common condition during pregnancy.

OBJECTIVE

We sought to determine the effect of asthma on the rates of adverse pregnancy and fetal outcomes.

METHODS

We identified pregnancies among black and white women age 15 to 44 with singleton gestations enrolled in the Tennessee Medicaid program over a period of 9 consecutive years, from 1995to 2003, and used claims data to determine the relationship of maternal asthma and asthma exacerbations on pregnancy and infant outcomes.

RESULTS

Among the 140,299 pregnancies, 6.5% were in women with asthma. Among women with asthma, 23% had a hospital or emergency department visit (exacerbated asthma); 40% of black and 23% of white women received hospital or emergency department care for asthma during pregnancy. After controlling for race and other covariates, birth weights among infants of women with asthma were, on average, 38 g lower, and among infants of women with exacerbated asthma they were, on average, 56 g lower. There were moderate, dose-dependent relationships between asthma alone and exacerbated asthma with hypertensive disorders of pregnancy, membrane-related disorders, preterm labor, antepartum hemorrhage, and cesarean delivery. Maternal asthma was not associated with preterm birth or birth defects.

CONCLUSION

Asthma is a risk factor for several common adverse outcomes of pregnancy, and poorly controlled asthma during pregnancy increases these risks.

CLINICAL IMPLICATIONS

It is possible that both maternal and infant outcomes could be improved in this population with appropriate asthma care, especially among black women.

Ambient air pollution and low birth weight in Connecticut and Massachusetts

BACKGROUND

Several studies have examined whether air pollution affects birth weight; however results vary and many studies were focused on Southern California or were conducted outside of the United States.

OBJECTIVES

We investigated maternal exposure to particulate matter with aerodynamic diameter < 10, < 2.5 microm (PM(10), PM(2.5)), sulfur dioxide, nitrogen dioxide, and carbon monoxide and birth weight for 358,504 births in Massachusetts and Connecticut from 1999 to 2002.

METHODS

Analysis included logistic models for low birth weight (< 2,500 g) and linear models with birth weight as a continuous variable. Exposure was assigned as the average county-level concentration over gestation and each trimester based on mother's residence. We adjusted for gestational length, prenatal care, type of delivery, child's sex, birth order, weather, year, and mother's race, education, marital status, age, and tobacco use.

RESULTS

An interquartile increase in gestational exposure to NO(2), CO, PM(10), and PM(2.5) lowered birth weight by 8.9 g [95% confidence interval (CI), 7.0-10.8], 16.2 g (95% CI, 12.6-19.7), 8.2 g (95% CI, 5.3-11.1), and 14.7 g (95% CI, 12.3-17.1), respectively. Lower birth weight was associated with exposure in the third trimester for PM(10), the first and third trimesters for CO, the first trimester for NO(2) and SO(2), and the second and third trimesters for PM(2.5). Effect estimates for PM(2.5) were higher for infants of black mothers than those of white mothers.

CONCLUSIONS

Results indicate that exposure to air pollution, even at low levels, may increase risk of low birth weight, particularly for some segments of the population.

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.

Proteomic study of plasma proteins in pregnant women with asthma

OBJECTIVE AND BACKGROUND

The course of asthma may be altered during pregnancy with at least one-third of women experiencing a worsening of asthma and 20% having an exacerbation during pregnancy. This study used the novel proteomic technique, surface-enhanced laser desorption ionization-time of flight mass spectrometry to determine if the presence of asthma during pregnancy was associated with alterations in plasma proteins.

METHODS

Plasma collected from healthy (n = 23) and asthmatic (n = 27) pregnant women at 18 and 30 weeks gestation was applied to strong anion exchange (SAX2), weak cation exchange (WCX2) and immobilized metal affinity capture (IMAC-Cu(2+)) chips. Mass analysis was conducted using Ciphergen Protein Biology System IIc and significant differences in individual peak intensities between groups determined.

RESULTS

At 18 weeks gestation, 91 peaks were significantly different between pregnant women with and without asthma, representing 28% of the total peaks identified. At 30 weeks gestation, 51 peaks were significantly different. There were two peaks that were significantly different between groups at both 18 and 30 weeks gestation and expressed at a similar level at both time points. One was increased in asthmatics (MW = 6444 Da) whereas the other decreased in asthmatics compared with non-asthmatic women (MW = 1846 Da).

CONCLUSIONS

This study demonstrated that there are differences in protein patterns between pregnant women with and without asthma. Other techniques are needed to define the molecular species and classify pathophysiological significance. Surface-enhanced laser desorption ionization-time of flight mass spectrometry has potential as a tool to monitor disease progression in situations such as pregnancy.

Effect of inhaled glucocorticoid treatment on placental 11beta-hydroxysteroid dehydrogenase type 2 activity and neonatal birthweight in pregnancies complicated by asthma

BACKGROUND

Asthma is a common disease affecting 12% of Australian women with 55% of women experiencing at least one exacerbation during pregnancy. Exacerbations during pregnancy are associated with low birthweight neonates and stillbirth. One of the main reasons for maternal exacerbations during pregnancy is non-compliance with inhaled glucocorticoid treatment due to the misconception that inhaled glucocorticoids are harmful to the fetus.

AIMS AND METHODS

We have therefore assessed whether the commonly used inhaled glucocorticoids reduce placental glucocorticoid metabolising capacity, by measuring 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD-2) activity. As these treatments potentially increase the exposure of the fetus to the growth-inhibiting effects of glucocorticoids, we also examined the question of whether inhaled glucocorticoid use was associated with reduced birthweight. Pregnant women using budesonide (n = 18), fluticasone propionate alone (n = 14) and fluticasone propionate in combination with the long-acting beta2 agonist salmeterol (n = 9) were compared to a non-asthmatic control group (n = 20).

RESULTS

The use of inhaled budesonide was associated with significantly increased placental 11beta-HSD-2 activity relative to the control group. Inhaled glucocorticoid use for the treatment of asthma was associated with normal birthweight. In the small number of women using combination therapy (fluticasone and salmeterol), there was reduced birthweight compared to the control group.

CONCLUSION

Inhaled glucocorticoids alone do not adversely affect fetal growth and placental function.

Endocrine regulation of human fetal growth: the role of the mother, placenta, and fetus

The environment in which the fetus develops is critical for its survival and long-term health. The regulation of normal human fetal growth involves many multidirectional interactions between the mother, placenta, and fetus. The mother supplies nutrients and oxygen to the fetus via the placenta. The fetus influences the provision of maternal nutrients via the placental production of hormones that regulate maternal metabolism. The placenta is the site of exchange between mother and fetus and regulates fetal growth via the production and metabolism of growth-regulating hormones such as IGFs and glucocorticoids. Adequate trophoblast invasion in early pregnancy and increased uteroplacental blood flow ensure sufficient growth of the uterus, placenta, and fetus. The placenta may respond to fetal endocrine signals to increase transport of maternal nutrients by growth of the placenta, by activation of transport systems, and by production of placental hormones to influence maternal physiology and even behavior. There are consequences of poor fetal growth both in the short term and long term, in the form of increased mortality and morbidity. Endocrine regulation of fetal growth involves interactions between the mother, placenta, and fetus, and these effects may program long-term physiology.

Metabolism of synthetic steroids by the human placenta

Pregnant women with asthma are frequently exposed to synthetic glucocorticoids and glucocorticoids are known to reduce fetal growth. The fetus is normally protected from the harmful effects of maternally derived glucocorticoids by the placental enzyme 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2). Whether 11beta-HSD2 inactivates the synthetic glucocorticoids used for asthma treatment during pregnancy (budesonide, beclomethasone dipropionate and fluticasone propionate) remains unknown. To investigate the relationship between steroid use during pregnancy and fetal growth and development, pregnant women with (n=119) and without asthma (n=84) were followed throughout pregnancy. Data on asthma medication use, neonatal size at birth, placental weight and cord blood cortisol and estriol were collected. Placental tissue samples were collected from non-asthmatic women (n=8) for metabolism studies. Placental 11beta-HSD2 activity was determined using beclomethasone dipropionate, budesonide, fluticasone propionate, prednisolone, dexamethasone and betamethasone as steroid substrates. Steroids and their oxidised metabolites were examined using thin layer chromatography and densitometry. Placental 11beta-HSD2 metabolised beclomethasone, prednisolone, dexamethasone and betamethasone, but not budesonide or fluticasone. No association between the use of inhaled steroids for asthma treatment during pregnancy and alterations in neonatal size, placental weight, gestational age at delivery, or umbilical vein estriol concentrations was demonstrated compared to non-asthmatic women. In conclusion, the use of inhaled steroids for asthma treatment does not affect fetal growth, despite differences in placental metabolism by 11beta-HSD2.

The effect of maternal asthma on placental and cord blood protein profiles

OBJECTIVE

We conducted a comparative proteomic analysis of placental and umbilical cord blood proteins using surface-enhanced laser desorption ionization-time of flight mass spectrometry (SELDI-TOF MS) to examine the associations among asthma, fetal gender, and protein profiles.

METHODS

Placental tissue and umbilical vein plasma were collected from 10 healthy and 20 asthmatic women. Placental proteins were extracted using phosphate-buffered saline containing protease inhibitors. Samples were applied to the surfaces of strong anion exchange (SAX2), weak cation exchange (WCX2) and immobilized metal affinity capture (IMAC-Cu(2+)) chips. Mass analysis was conducted using a Ciphergen Protein Biology System IIc (Freemont, CA), and differences in individual peak intensities between groups were determined.

RESULTS

Fourteen placental peaks were significantly different between asthmatic and non-asthmatic women (seven more highly expressed and seven less highly expressed). Ten umbilical cord blood peak differences were identified, with four peaks more highly expressed and six peaks less highly expressed in asthmatics. Four placental and three umbilical cord blood proteins differed significantly between male and female fetuses. Two placental and five umbilical cord blood peaks were specifically increased in a subgroup of samples collected from asthmatic women who did not use inhaled glucocorticoids and were pregnant with a female fetus, a group previously found to have altered placental function.

CONCLUSIONS

This study demonstrates the abilities of the SELDI technique as a tool for protein profiling in tissue or plasma. Further work to positively identify the candidate peptides found in this study may provide a greater understanding of the placental mechanisms leading to alterations in fetal growth in patients with bronchial asthma.

Asthma exacerbations during pregnancy: incidence and association with adverse pregnancy outcomes

Exacerbations of asthma during pregnancy represent a significant clinical problem and may be related to poor pregnancy outcomes. A systematic review of the literature was conducted for publications related to exacerbations during pregnancy. Four studies with a control group (no asthma) and two groups of women with asthma (exacerbation, no exacerbation) were included in meta-analyses using fixed effects models. During pregnancy, exacerbations of asthma which require medical intervention occur in about 20% of women, with approximately 6% of women being admitted to hospital. Exacerbations during pregnancy occur primarily in the late second trimester; the major triggers are viral infection and non-adherence to inhaled corticosteroid medication. Women who have a severe exacerbation during pregnancy are at a significantly increased risk of having a low birth weight baby compared with women without asthma. No significant associations between exacerbations during pregnancy and preterm delivery or pre-eclampsia were identified. Inhaled corticosteroid use may reduce the risk of exacerbations during pregnancy. Pregnant women may be less likely to receive oral steroids for the emergency management of asthma. The effective management and prevention of asthma exacerbations during pregnancy is important for the health of both the mother and fetus.