死亡原因としては前期では奇形，呼吸適応障害，未熟性，仮死および分娩外傷，感染症，その他の順であり，後期でも奇形が最も多く，感染症，未熟性，呼吸適応障害，その他，仮死および分娩外傷の順であった。
医療技術の進歩に伴い呼吸適応障害による死亡例が減少し，未熟性や感染症が死亡原因として増加していた。死亡率の低下は各種診断・医療技術の進歩を反映していると同時に，診断技術の進歩は剖検率の低下につながっていると思われた。しかしながら，どんなに医療技術が進歩しても，病理解剖の意義は大きく，今後も剖検率の維持と向上の努力の継続を要すると思われる。
Since the establishment of our department, two study periods were divided and compared each other；the first half period（1976-1995）consists of 710 autopsy cases and the second half（1996-2005）of 120 cases.
The overall autopsy rate was 74.1％ in the first half period and 46.5％ in the second half, respectively.
We classified the causes of death into 6 categories；1）Prematurity, 2）Pulmonary maladaption, 3）Asphyxia/birth injury, 4）Congenital anomalies（including chromosomal anomality）, 5）Infection, 6）Miscellanous.
The improved perinatal and neonatal care dramatically decreased the number of deaths from pulmonary maladaption, in the second half period. Instead, infections appeared as a major cause of death because the longer survival chances were given to the premature infants. Congenital anomalies remained the most frequent cause of deaths throughout the study period（46％ in the first half period and 50％ in the second half, respectively）.
Although newly introduced diagnostic technologies have disclosed many concealed causes of death, they did not contribute to the autopsy rate.
