DISCUSSION
anaemia, autism spectrum, high‐dose iron, hyperactivity, neurodevelopmental disorders
ANAEMIA, ADVERSE EFFECTS, EARLY PREGNANCY
The present study found that adapting prenatal iron supplementation in non‐anaemic women according to their Hb levels and iron reserves in early pregnancy would reduce behavioural problems in children aged 4 years. We obtained information from both parents and teachers and observed that the relationship between iron supplementation adjusted to maternal baseline SF levels and children's behavioural problems was more evident when considering information reported by parents. Some studies have previously shown differences between the data reported by different informants, with parents more frequently rating their children higher than teachers on behavioural problems and hyperactivity (Sans et al., To the best of our knowledge, this is the first study that considers together Hb level and iron stores at the beginning of pregnancy to evaluate the effect of different doses of prenatal iron supplements on the child's behavioural problems, which makes it difficult to compare the current results. Previous studies evaluating the effects of routine prenatal iron supplementation with a single dose of iron failed to provide clear evidence of benefits. As it is well known that both ID and excess during pregnancy can have long‐term consequences on the child's neuropsychological development and increase the risk of behavioural problems by being detrimental to the development and maturation of the fetal brain, one could argue that having administered a single dose to all women in those studies may have been insufficient or excessive, depending on the case, to observe positive effects or even to report, by contrary, adverse effects after prenatal supplementation.It is worth mentioning that as anaemia was an exclusion criterion for participation in the study, none of the participants was anaemic at the beginning of pregnancy, but some of them showed ID at that time. Further, this point is relevant in the present study, because the differences found in the effect of prenatal iron doses on children's behavioural problems depended on women's iron stores at the beginning of pregnancy beyond their Hb levels. Specifically, prenatal administration of high‐dose iron (80 mg/day) in women with normal Hb concentration improved, according to information reported by parents, most of the executive functions and reduced all the behavioural problems in their 4‐year‐old children when the women had baseline ID, whereas it resulted in worse scores for some items about executive functioning, as well as for internalizing, externalizing and total problems, and most DSM scales, specifically autism spectrum problems in the children of those who began pregnancy with normal‐high iron stores (SF ≥ 65 µg/L). This is consistent with previous results from our own study regarding different scales of child cognitive development (Iglesias‐Vázquez et al., That a high prenatal iron dose improves the behaviour and executive functioning and reduces behavioural problems of children when women entered the pregnancy with ID was an expected finding. Indeed, there is abundant evidence in the literature that low iron status during pregnancy is associated with an increased risk of a wide range of neurodevelopmental disorders in children (Gaillard et al., 