Maternal iron status during pregnancy and attention deficit/hyperactivity disorder symptoms in 7-year-old children: a prospective cohort study

Evidence suggests that iron status may be linked to symptoms of childhood attention deficit/hyperactivity disorder (ADHD), but there is little data available on the relationship between iron status in pregnancy and the risk of developing ADHD. And the data that does exist is inconsistent. Our aim here is to assess the effect of maternal serum ferritin (SF) and haemoglobin (Hb) levels during pregnancy on manifestations of ADHD in children at 7 years of age. This prospective study analysed data from 1204 mother-child pairs from three Spanish cohorts participating in the INMA project. Maternal SF and Hb levels during pregnancy and other mother and child characteristics were collected. The children's ADHD behaviours were reported by their parents using Conners' Parent Rating Scale-Revised Short Form (CPRS-R:S). In the unadjusted regression analysis, maternal SF was positively associated with children's T-scores on the subscales Cognitive problems/Inattention (β: 0.63, 95%CI 0.06-1.19; p = 0.029) and ADHD index (β: 0.72, 95%CI 0.20-1.24; p = 0.007). These associations were not present after multivariate adjustment or stratification by first and second trimester of pregnancy. The Hb levels were not related to any of the CPRS-R:S subscales in unadjusted or multivariate-adjusted models. We observed no association between maternal SF or Hb levels and the risk of ADHD symptomatology (T-score ≥ 65 for CPRS-R:S subscales). Our results suggest that neither maternal SF nor Hb levels during pregnancy are related to ADHD symptoms in 7-year-old children.This work was supported by official Spanish institutions that fund scientific biomedical research, the Instituto de Salud Carlos III (ISCIII) through the projects CP14/00108 & PI16/00261, which is co-funded by European Regional Development Fund ‘A way to make Europe’. A.D. is a Serra Hunter Fellow, Spain. J.J., S.L., and M.G. hold the Miguel Servet-II contract (CPII19/00015, CPII20/00006, and CPII18/00018) awarded by the Spanish ISCIII (Ministry of Economy and Competitiveness). This study was additionally funded by Grants from ISCIII (Red INMA G03/176; CB06/02/0041; FIS-FEDER: PI03/1615, PI04/1509, PI04/1112, PI04/1931, PI041436, PI05/1079, PI05/1052, PI06/1213, PI07/0314, PI081151, PI09/02647, PI11/01007, PI11/02591, PI11/02038, PI13/1944, PI13/2032, PI14/00891, PI14/01687, PI16/1288, PI17/00663, and PI19/1338), CIBERESP, Generalitat de Catalunya-CIRIT 1999SGR 00241, Generalitat de Catalunya-AGAUR 2009SGR 501, TV3’s La Marató foundation (090430), EU Commission (261357). ISGlobal is a member of the CERCA Program of the Government of Catalonia. This study was additionally funded by EU Grants (FP7-ENV-2011 cod 282957 and HEALTH.2010.2.4.5-1), Government of Valencia: FISABIO (UGP 15-230, UGP-15-244, and UGP-15-249), and the Alicia Koplowitz Foundation, 2017. None of the funding sources took part in the design, collection, analysis, interpretation of data, writing of the report, or the decision to submit the manuscript for publication