Eleven-Year Trends in Stillbirth, Neonatal and Infant Mortality and Birthweight-Specific Risk: A BABIES Matrix Analysis from a Tertiary Maternity Center in Kazakhstan, 2015–2025

Background/Objectives: Long-run facility-level perinatal data from Central Asia are scarce. We described eleven years of stillbirth, neonatal, infant and perinatal mortality at one tertiary maternity center in Kazakhstan, and used the Birthweight and Age-at-death Boxes for Intervention and Evaluation System (BABIES) matrix to locate where feto-infant deaths concentrated. Methods: Retrospective ecological analysis of aggregated annual institutional records, 2015–2025: 102,481 total births, 101,544 live births, 937 stillbirths and 489 infant deaths. Rates were modeled by Poisson regression with the log birth denominator as offset, refitted as quasi-Poisson and negative binomial. Composite feto-infant mortality (antenatal and intrapartum stillbirth plus death at 0–27 days, per 1000 total births in each birthweight band) was examined by direct standardization and Kitagawa decomposition, using the nine years whose matrix cells reconciled with the registry. The study was not preregistered. Results: Infant mortality fell from 7.07 to 3.57 per 1000 live births (rate ratio 0.50, 95% CI 0.33–0.77) and stillbirth from 10.07 to 5.42 per 1000 total births (0.54, 0.38–0.76), an average annual decline near 8% for neonatal and infant mortality. Antenatal stillbirth declined; no clear change was detected for intrapartum stillbirth (1.11 to 1.04 per 1000; 0.94, 0.38–2.32). Births below 2500 g were 5.9% of all births but 71.1% of composite feto-infant deaths (rate ratio 39). Decomposition placed the reduction within birthweight bands rather than in the birthweight distribution, in single-year and pooled-period versions. Conclusions: The design is ecological and descriptive: it shows where feto-infant deaths are concentrated, not why. Intrapartum stillbirth and births below 2500 g are the groups in which any further reduction would have to be found.