Understanding stillbirth: a retrospective cohort study using WHO ICD-PM criteria at a tertiary perinatal center in Germany

Abstract Objectives The aim of this study was to identify maternal and fetal risk factors associated with stillbirth and to differentiate intrauterine fetal death (IUFD) from late termination of pregnancy (TOP). Methods Analyses were performed on births from 2014 to 2024 at Charité Berlin, characterizing the overall cohort, IUFD, and TOP, respectively. Descriptive characterizations and regressions were applied to evaluate the impact of modifiable risk factors and trends within the overall study cohort and 3rd trimester IUFDs. Results Three hundred and eighty five stillbirths and 58,631 live births were identified (59,016 births, 0.65 % stillbirths). Of these, 177 (46 %) were categorized as IUFD and 208 (54 %) as TOP. The stillbirth rate rose from 0.45 % (2014) to 1.2 % (2024) (odds ratio 1.13, p<0.001). Advanced maternal age, higher maternal BMI before pregnancy, and smoking during pregnancy were associated with stillbirths p<0.01. TOPs and IUFDs differed in their occurrence time (most IUFDs in 28-36+6 weeks of pregnancy [44 %], most TOPs 20-27+6 weeks [75 %; p<0.001]) and in terms of their risk profiles (IUFDs associated with higher gravity, parity and BMI as well as higher rates of multiple gestations compared to TOPs). Differences in disease burden (WHO ICD-PM criteria) were not significant over the year but formed a distinct contrast between IUFD and TOP. 3rd trimester IUFD was associated with higher parity, gravidity and BMI (p<0.05). Conclusions IUFD and TOP cohorts naturally represent different risk profiles. As cohort size and power limited analytical possibilities standardized, differentiated recording and data pooling is crucial to advance stillbirth research and develop effective preventive strategies targeting modifiable risk factors.