Objective Assess the mental health, physical health, cognitive and language development of 10-year old children in families where mothers have reported intimate partner violence (IPV) compared with children with no reported IPV exposure.

Design Prospective pregnancy cohort. Maternal report of IPV (Composite Abuse Scale) at 1, 4 and 10 years. Maternal and direct assessment of child mental health (probable psychiatric diagnosis, anxiety and emotional/behavioural difficulties), cognition (IQ and executive function), language (general, pragmatic and receptive) and physical health at 10 years.

Setting A subsample of 615 mother–child dyads drawn from a pregnancy cohort of 1507 nulliparous women recruited from six public hospitals in Melbourne, Australia.

Results Any IPV exposure from infancy to age 10 was associated with poorer child outcomes at age 10. Specifically, twice the odds of a probable psychiatric diagnosis, emotional/behavioural difficulties, impaired language skills (general and pragmatic), and having consulted a health professional about asthma or sleep problems. IPV exposure at age 10 associated with two to three times higher odds of all mental health outcomes, elevated blood pressure and sleep problems. Early life exposure alone (at 1 and/or 4 years) associated with three times higher odds of a general language problem and asthma at age 10.

Conclusion The high prevalence of IPV and increased risk of poorer health and development among children exposed highlights the burden of ill health carried by children in families experiencing IPV. Fewer difficulties where exposure was limited to the early years builds the case for better identification, understanding and resourcing of effective early intervention.