Maternal anaemia diagnosed before 31 weeks’ gestation is associated with an increased risk of neurodevelopmental disorders in offspring, a study shows.

Swedish researchers have found that anaemia in early pregnancy is linked to double the risk of the child having an intellectual disorder, and also to increased risks of autism and ADHD.

The associations account for potentially confounding socioeconomic, maternal and pregnancy-related factors, the authors say, and were not apparent when anaemia was diagnosed later in the pregnancy.

The researchers evaluated health data from 300,000 mothers and their 530,000 children — the Stockholm Youth Cohort — who were born between 1987 and 2010, and followed until the end of 2016.