James W H
Ann Hum Biol. 1980 Mar-Apr;7(2):163-75. doi: 10.1080/03014468000004191.
A study has been made of the twin births in England and Wales 1952-59 and 1963-75. There is good evidence that the incidence of opposite-sexed (and by inference, dizygotic) twin births is seasonal, being about 5% higher in December than June. Triplet births seen to show a seasonal variation at about the same location and with double the amplitude. It seems likely that this seasonal variation of polyzygotic maternities is due to seasonal variation in the rates of multiple ovulation rather than to seasonal variation in any of the other reproductive parameters which could, in principle, be responsible (coital rate, spontaneous abortion, probability of fertilization). It is possible that such an hypothesized variation is due to seasonal variation in food consumption. Evidence in regard to seasonal variance in monozygotic twinning rates is equivocal but a number of considerations suggest that they too are subject to seasonal variation. If this is so, the peak incidence of MZ twin births occurs around November.
对1952 - 1959年以及1963 - 1975年英格兰和威尔士的双胞胎出生情况进行了一项研究。有充分证据表明，异性（由此推断为异卵）双胞胎出生的发生率具有季节性，12月比6月高出约5%。三胞胎出生似乎在大致相同的位置呈现季节性变化，且幅度为双胞胎的两倍。多合子生育的这种季节性变化似乎是由于多次排卵率的季节性变化，而非原则上可能起作用的任何其他生殖参数（性交频率、自然流产、受精概率）的季节性变化。这种假设的变化有可能是由于食物摄入量的季节性变化。关于单卵双胞胎发生率季节性差异的证据并不明确，但一些因素表明它们也会受到季节性变化的影响。如果是这样，单卵双胞胎出生的高峰发生率出现在11月左右。
