To examine the association between birth intervals and perinatal mortality in Indonesia.

Cross-sectional study using reproductive calendar data from the 2017 Indonesia Demographic and Health Survey.

Nationally representative households in Indonesia.

A total of 17 171 women aged 15–49 with pregnancies in the 5 years preceding the survey. Women with missing data or multiple births were excluded.

Perinatal mortality, defined as stillbirths and early neonatal deaths.

The perinatal mortality rate was 22 per 1000 births. Short birth intervals (

Short and long birth intervals were associated with higher perinatal mortality in Indonesia, with additional associations observed for antenatal care visits, maternal age and newborn sex. These findings underscore the importance of promoting healthy birth spacing within maternal and child health programmes and integrating postpartum family planning into routine care. Further longitudinal research is needed to confirm causal pathways and inform targeted interventions.