Imaizumi Y
Institute of Population Problems, Ministry of Health and Welfare, Tokyo, Japan.
Paediatr Perinat Epidemiol. 1994 Apr;8(2):205-15. doi: 10.1111/j.1365-3016.1994.tb00451.x.
Perinatal mortality rates (PMR) decreased significantly per year in single, twin, triplet, quadruplet and quintuplet births during the period 1980-1991. The PMRs were 7.7 per 1000 livebirths for singletons, 45.6 for twins, 89.0 for triplets, 116.8 for quadruplets, and 476.2 for quintuplets during the 12 years. The relative risks of perinatal death in multiplets vs. singletons were 6 for twins, 12 for triplets, 15 for quadruplets and 62 for quintuplets. The PMR was significantly higher in males than females for singletons and twins, but there was no sex differential in PMRs for higher order of multiple births. The PMR increased with birth order in twins and triplets, whereas there was no birth order effect on the PMR for quadruplets. An increasing proportion of multiple births among perinatal deaths may be related to the increasing multiple birth rate in Japan.
1980年至1991年期间，单胎、双胎、三胎、四胎和五胎分娩的围产期死亡率（PMR）逐年显著下降。在这12年中，单胎的围产期死亡率为每1000例活产7.7例，双胎为45.6例，三胎为89.0例，四胎为116.8例，五胎为476.2例。多胎与单胎相比，围产期死亡的相对风险分别为：双胎6倍，三胎12倍，四胎15倍，五胎62倍。单胎和双胎中男性的围产期死亡率显著高于女性，但多胎分娩中围产期死亡率不存在性别差异。双胎和三胎的围产期死亡率随出生顺序增加，而四胎的围产期死亡率不受出生顺序影响。围产期死亡中多胎分娩比例的增加可能与日本多胎出生率的上升有关。
