Background Childbirth-related post-traumatic stress disorder (CB-PTSD) is an important international health concern. Despite increasing recognition of the public health burden of CB-PTSD, little is known about how CB-PTSD symptoms present across different countries. Aims This study examined cross-national differences in CB-PTSD symptom severity and presentation to inform culturally sensitive screening and intervention strategies. Method Data were drawn from the International Survey of Childbirth-Related Trauma (INTERSECT) cross-sectional survey of 11,302 women 6–12 weeks postpartum in 31 countries using a standard protocol. CB-PTSD symptoms were assessed using the City Birth Trauma Scale, measuring DSM-5 symptom components (re-experiencing, avoidance, negative cognitions and mood, hyperarousal). Results Participants were mostly married, aged 30–34 years, with average household income, and higher education. CB-PTSD symptom severity varied substantially across countries, with the highest mean scores in Pakistan (M = 23.49, SD = 13.23) and lowest in Nigeria (M = 1.89, SD = 3.66). Despite these differences, symptom patterns were largely consistent across countries, with avoidance symptoms lowest and hyperarousal symptoms highest. Exceptions were observed in countries with particularly high symptom levels. Decision tree analysis identified avoidance symptoms (>3.1) as the strongest discriminator of CB-PTSD cases vs non-cases (F(1,11,204) = 4820.54, p = .000), followed by negative cognitions and mood (>10; F(1,716) = 143.69, p = .000). Conclusions While CB-PTSD severity varies internationally, symptom presentation is largely consistent, supporting its relevance as an international construct. Avoidance symptoms were the least commonly endorsed yet the most discriminative for identifying CB-PTSD in decision tree analyses, suggesting they may serve as a useful clinical flag for women who warrant more detailed assessment. Variations in symptom expression in countries with high levels of symptoms highlight the importance of culturally sensitive approaches to screening and assessment.