Maternal iron deficiency anaemia and risk of cardiac abnormalities in newborns
M B Fosgaard, A F Mariager, A M Dehn, A A Raja, A S Sillesen, R O B Voegg, H A Boyd, R Frikke-Schmidt, H Bundgaard, K K IversenAbstract
Background
Congenital heart defects (CHD) are the most common birth defects. Maternal iron deficiency anaemia (IDA) early in pregnancy is a risk factor for major CHDs in the offspring. In this population-based study, we determined the prevalence of first-trimester IDA among mothers of newborns and investigated its association with minor CHD and changes in left ventricular structure and function in the offspring.
Purpose
To evaluate whether maternal IDA is associated with minor CHDs and neonatal cardiac parameters.
Methods
This study included all participants from a large, prospective cohort in Northern Europe with systematic neonatal transthoracic echocardiography and available first-trimester maternal haemoglobin and serum ferritin measurements. Maternal IDA was defined by four approaches based on World Health Organization (WHO) definitions for pregnant and non-pregnant women: IDA group A (true IDA in pregnancy), haemoglobin <110 g/L and ferritin <15 μg/L; IDA group B (low or depleted iron stores in pregnancy), haemoglobin <110 g/L and ferritin ≤30 μg/L; IDA group C (definition of low iron outside pregnancy), haemoglobin <120 g/L and ferritin <15 ug/L; and IDA group D (definition of true IDA outside pregnancy) haemoglobin <120 g/L and ferritin <15 μg/L. Newborns were considered unexposed if maternal haemoglobin was >120 g/L and ferritin >30 μg/L. Associations between maternal IDA and minor CHDs, including atrial septal defects, ventricular septal defects, bicuspid aortic valve, and persistent ductus arteriosus, were assessed using chi-squared tests. Fisher’s exact test was used when expected frequencies were <5. Using multiple linear regression, we estimated mean differences in left ventricular structural and functional parameters from echocardiography between newborns exposed to maternal IDA and unexposed newborns, adjusting for weight at examination.
Results
A total of 4,713 mothers had both haemoglobin and serum ferritin measurements obtained on the same date during the first trimester. The prevalence of maternal IDA in the first trimester was 1,2%, 1,5%, 2% and 3,8% for IDA definition A, B, C and D respectively. We observed no statistically significant associations between maternal IDA and the risk of CHDs or differences in left ventricular structural or functional parameters in newborns, regardless of the IDA definition used.
Conclusion
In this study of over 4,000 newborns, first-trimester maternal IDA was not associated with an increased risk of minor CHD or differences in left ventricular structure or function.