Maternal haemoglobin levels and cardio-metabolic risk factors in childhood: the Generation R Study

ObjectiveTo assess whether variations in maternal haemoglobin levels during pregnancy are associated with cardio-metabolic risk factors in school age children. DesignPopulation-based prospective cohort study. SettingRotterdam, The Netherlands, 2002-2012. PopulationMothers and children (n=5002) participating in the Generation R Study. MethodsWe obtained maternal haemoglobin levels during early pregnancy (median gestational age 14.6weeks [95% range 10.3, 25.3]) from venous blood samples. Maternal anaemia and elevated haemoglobin levels were based on World Health Organization criteria. We measured childhood cardio-metabolic risk factors at age 6years. Main outcome measuresCardio-metabolic risk factors included body mass index, total fat mass percentage, android/gynoid fat mass ratio, systolic and diastolic blood pressure, left ventricular mass, and blood levels of cholesterol, insulin and C-peptide. ResultsMaternal haemoglobin levels were not associated with childhood body mass index, total fat mass percentage, android/gynoid fat mass ratio, systolic blood pressure, cholesterol or insulin levels. Compared with children with normal maternal haemoglobin levels, children from anaemic mothers had slightly higher diastolic blood pressures (difference 0.70mmHg, 95% CI 0.12, 1.29) and lower C-peptide levels (difference factor 0.93, 95% CI 0.88, 0.98), and children of mothers with elevated haemoglobin levels had lower left ventricular masses (difference -1.08g, 95% CI -1.88, -0.29). These associations attenuated after adjustment for multiple testing and were not consistent within linear models. ConclusionThese results do not strongly support the hypothesis that variations in maternal haemoglobin levels during pregnancy influence cardio-metabolic risk factors in childhood.