MacGillivray I
Acta Genet Med Gemellol (Roma). 1979;28(4):289-91. doi: 10.1017/s0001566000008801.
The urinary nitrogen output appears to be related to both protein and energy intake, so that women having heavier babies probably eat more, although this may simply mean that they are larger women. Women with twin pregnancies have been found to have a lesser urinary nitrogen output, but it seems unlikely that this be due to lower intakes. They might simply utilize their diet more efficiently--a hypothesis that is now being tested.
尿氮排出量似乎与蛋白质和能量摄入都有关,因此生下较重婴儿的女性可能吃得更多,尽管这可能仅仅意味着她们体型更大。已发现怀有双胞胎的女性尿氮排出量较少,但这似乎不太可能是由于摄入量较低。她们可能只是更有效地利用了饮食——这一假设目前正在接受检验。