OBJECTIVES: To examine the impact of antenatal psychosocial stressors, including maternal common mental disorders (CMD), upon low birth weight, stillbirth and neonatal mortality, and other perinatal outcomes in rural Ethiopia. METHODS: A population-based sample of 1065 pregnant women was assessed for symptoms of antenatal CMD (Self-Reporting Questionnaire-20: SRQ-20), stressful life events during pregnancy (List of Threatening Experiences: LTE) and worry about the forthcoming delivery. In a sub-sample of 654 women from six rural sub-districts, neonatal birth weight was measured on 521 (79.7%) singleton babies within 48 h of delivery. Information about other perinatal outcomes was obtained shortly after birth from the mother's verbal report and via the Demographic Surveillance System. RESULTS: After adjusting for potential confounders, none of the psychosocial stressors were associated with lower mean birth weight, stillbirth or neonatal mortality. Increasing levels of antenatal CMD symptoms were associated both with prolonged labour (>24 h) (SRQ 1-5: RR 1.4; 95% CI 1.0-1.9, SRQ >or= 6: RR 1.6; 95% CI 1.0-2.6) and delaying initiation of breast-feeding more than eight hours (SRQ 1-5: RR 1.4; 95% CI 0.8 to 2.4, SRQ >or= 6: RR 2.8; 95% CI 1.3-6.1). Worry about delivery was also associated with labour longer than 24 h (RR 1.5; 95% CI 1.0-2.1). CONCLUSIONS: This study provides preliminary evidence of important public health consequences of poor maternal mental health in low-income countries but does not replicate the strong association with low birth weight found in South Asia.