We explored the association between caregiving for preschool children with developmental disabilities and maternal health and healthcare use using linked primary care and Born in Bradford birth cohort data. Adjusting for prenatal health, healthcare use and socioeconomic status, mothers who were caregivers were more likely than other mothers to have symptoms of psychological distress (odds ratio 1.24; 95% CI 1.01, 1.53), exhaustion (1.42; 1.12, 1.80) and possibly head and musculoskeletal pain (1.18; 0.97, 1.43). Despite the higher prevalence of symptoms, they did not access healthcare services more and may seek healthcare for psychological distress less often (0.64; 0.40, 1.02). In general, socioeconomic disadvantage was associated with worse health. Pakistani ethnicity (versus white British) and prenatal consultation were strongly associated with higher postnatal consultation rates. Prenatal ill health, healthcare use and socioeconomic status are important factors in the detection of postnatal ill health via primary care services. If caregiver burden and the risk of under-detecting (and thus under treating) caregiver ill health is not addressed during the preschool period health inequalities between caregivers and other mothers and their families may persist and grow. The health of mothers of young disabled children, in particular their unmet health needs, warrants attention in research and clinical practice.