Krueger J, Propping P
Acta Genet Med Gemellol (Roma). 1976;25:36-40. doi: 10.1017/s0001566000013799.
The decline of the twinning rate in Germany since 1900 is exclusively due to a fall of the DZ rate. The analysis of the birth data in Baden-Württemberg from 1955 to 1972 shows that the decline of the DZ twinning rate can be explained only to a small extent by the shift of the maternal age-parity distribution towards younger mothers and lower parities. It appears reasonable that the greater part of this decline is caused by the lessening prevalence of the more fecundable, DZ twin-prone women due to the growing influence of family planning. Furthermore, it is imaginable that the probability for multiple ovulation is decreased after cessation of hormonal contraception.
自1900年以来，德国双胞胎出生率的下降完全是由于异卵双胞胎出生率的下降。对1955年至1972年巴登-符腾堡州出生数据的分析表明，异卵双胞胎出生率的下降只能在很小程度上通过母亲年龄-胎次分布向更年轻母亲和更低胎次的转变来解释。似乎有理由认为，这种下降的很大一部分是由于计划生育影响的增加，导致生育能力更强、易生异卵双胞胎的女性比例减少。此外，可以想象，停止激素避孕后多排卵的概率会降低。
