postterm delivery

...The number of months of pregnancy is not calculated based on calendar days, but on 4 weeks as 1 month, and is called the xxth month of pregnancy. A birth that is not viable before 24 weeks of pregnancy is called a miscarriage, a birth between 24 and 37 weeks is called a preterm delivery, a birth between 37 and 42 weeks is called a term delivery, and a birth over 42 weeks is called a postterm delivery. Until 1978, a birth weight of 2500g or less was called premature, but because weight and prematurity are not necessarily in balance, a birth weight of less than 2500g came to be called a low birth weight infant. ...

*Some terminology explanations that mention "postterm delivery" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…また妊娠月数は暦日によるのではなく，4週をもって1月として数えて計算し，妊娠第○月とする。妊娠24週未満の児の生存が不可能な出産は流産とし，24週から37週未満を早産preterm delivery,37週から42週未満を正期産term delivery,42週以上を過期産postterm deliveryという。1978年までは出産体重2500g以下を未熟児と呼んでいたが，体重と未熟性とは必ずしも平衡しないことから，出産体重2500g未満を低出産体重児low birth weight infantと呼ぶことになった。…

※「postterm delivery」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報