Abstract
SummaryBackgroundLimited epidemiological evidence suggests that low maternal iron status and anaemia in pregnancy may increase the risk of childhood respiratory and allergic outcomes.ObjectivesTo investigate the relation between maternal haemoglobin concentrations in pregnancy and childhood respiratory and allergic outcomes.MethodsIn the Avon Longitudinal Study of Parents and Children (ALSPAC), we examined associations of maternal haemoglobin concentrations (g/dL) in pregnancy with hayfever, eczema, wheezing, doctor‐diagnosed asthma, allergic sensitisation and total IgE at 7 years, and with lung function at 8‐9 years in the offspring, after controlling for potential confounders (N = 3234‐5335).ResultsMaternal haemoglobin was not associated with offspring hayfever, eczema, wheezing or asthma. However, the first haemoglobin measurement in pregnancy (<18 weeks' gestation) and the last measurement (>28 weeks' gestation) were negatively associated with allergic sensitisation (adjusted odds ratio [95% CI] per g/dL 0.91 [0.83 to 0.99] and 0.90 [0.83 to 0.98], respectively). The last haemoglobin measurement was also negatively associated with total IgE (adjusted geometric mean ratio 0.94 [0.88 to 0.99]). Anaemia (haemoglobin <11 g/dL) in late pregnancy was negatively associated with forced vital capacity (difference in standard deviation score −0.07 [−0.13 to −0.01]).Conclusions and Clinical RelevanceLower maternal haemoglobin in pregnancy may be a risk factor for allergic sensitisation, elevated IgE and lower FVC in childhood, which may reflect effects of lower prenatal iron status. However, maternal haemoglobin was not associated with risk of childhood asthma or other allergic disorders.
Highlights
There is a substantial body of epidemiological evidence implicating the prenatal environment in the aetiology of childhood respiratory and allergic disorders,[1] and there has been considerable interest in the possible role of maternal nutrition during pregnancy.[2]
The first clues that prenatal iron status might be important came from the Avon Longitudinal Study of Parents and Children (ALSPAC), the study used in this paper, in which we found that umbilical cord iron concentration in over 2000 participants was negatively associated with wheezing and eczema in early childhood.[10]
The authors found some evidence to suggest that different indicators of lower maternal iron status in early gestation were associated with an increased risk of wheezing and lower lung function in the offspring at 10 years of age, findings were inconsistent across the different indicators, and no associations were found with asthma or eczema.[11]
Summary
There is a substantial body of epidemiological evidence implicating the prenatal environment in the aetiology of childhood respiratory and allergic disorders,[1] and there has been considerable interest in the possible role of maternal nutrition during pregnancy.[2]. Gestational age at delivery and offspring birthweight are associated with maternal haemoglobin concentration,[4] as well as with offspring wheezing, asthma, eczema, allergic sensitisation and impaired lung function.[5,6,7,8] animal data suggest that an adequate supply of iron is required for optimal lung, and airway, development.[9]. The authors found some evidence to suggest that different indicators of lower maternal iron status in early gestation were associated with an increased risk of wheezing and lower lung function in the offspring at 10 years of age, findings were inconsistent across the different indicators, and no associations were found with asthma or eczema.[11] A small study from the USA (n = 97) suggested that poor foetal iron status may increase the risk of infant eosinophilia.[12]
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