Kato Noriko, Matsuda Tomohiro
Department of Education Training Technology and Development, National Institute of Public Health, Saitama, Japan.
Twin Res Hum Genet. 2006 Apr;9(2):292-7. doi: 10.1375/183242706776382365.
This study aimed to evaluate the prevalence of birthweight discordance among twins, to determine the risk cut-off point for birthweight discordance, and to clarify whether perinatal deaths are aggravated by birthweight discordance or by low birthweight itself. A population-based analysis of all twins born between 1995 and 1999 in Japan was conducted using data collected from national birth, death and stillbirth certificates. Birthweight discordance was determined as: higher birthweight minus lower birthweight divided by higher birthweight multiplied by 100. Among twins with a birthweight discordance of more than 15%, the fetal and perinatal mortality rate was higher than that of twins with a discordance of less than 15%. Ninety per cent of the relative cumulative frequency of twin live-births were within 25% of the birthweight discordance. Logistic regression analysis showed that the stillbirth of at least one of the twins is associated with the birthweight of the larger twin and birthweight discordance. It also showed that the stillbirth of both twins in the twin pair is associated with the birth-weight of larger twins and the gestational weeks. It was clarified that birthweight discordance was associated with the stillbirth of only one twin in the twin pair, and the stillbirth of both twins in the twin pair was associated with low birthweight itself.
本研究旨在评估双胞胎出生体重不一致的患病率，确定出生体重不一致的风险临界点，并阐明围产期死亡是由出生体重不一致还是低出生体重本身加剧的。利用从国家出生、死亡和死产证明收集的数据，对1995年至1999年在日本出生的所有双胞胎进行了基于人群的分析。出生体重不一致的定义为：较高出生体重减去较低出生体重，再除以较高出生体重，然后乘以100。在出生体重不一致超过15%的双胞胎中，胎儿和围产期死亡率高于不一致低于15%的双胞胎。双胞胎活产相对累积频率的90%在出生体重不一致的25%以内。逻辑回归分析表明，至少有一个双胞胎死产与较大双胞胎的出生体重和出生体重不一致有关。分析还表明，双胞胎对中两个双胞胎均死产与较大双胞胎的出生体重和孕周有关。结果表明，出生体重不一致与双胞胎对中仅一个双胞胎死产有关，而双胞胎对中两个双胞胎均死产与低出生体重本身有关。
