Objective: Maternal eating disorders (EDs) are associated with adverse pregnancy and child outcomes. There is limited research investigating the influence of maternal EDs on foetal brain development. Method: Using foetal magnetoencephalography (fMEG), an auditory sequence was presented for 10 min to assess brain response latencies in foetuses of mothers with (n = 12) and without (n = 11) a history of anorexia nervosa (AN) in the third trimester of pregnancy. ED history and severity were assessed using the structured clinical expert interview eating disorder examination (EDE) and the self-report questionnaire EDE-Q. Results: Foetuses of mothers with AN showed delayed foetal brain responses to auditory stimulation compared to foetuses of control women. Self-reported ED symptom severity explained 34% of variance in foetal brain response latencies in the AN group. Conclusions: ED pathology was strongly associated with foetal brain response latencies in the third trimester with longer latencies in foetuses of women with a history of AN reporting more ED symptoms. Follow-up on the children is pivotal to investigate if fMEG outcomes are associated with later child development.