Czeizel A, Pazonyi I, Métneki J, Tomka M
Acta Genet Med Gemellol (Roma). 1979;28(1):73-6. doi: 10.1017/s0001566000009375.
The Budapest Twin Register recorded 88.6% of the 1739 multiple births that occurred between 1970 and 1974. Of these, 31.2% were male-female pairs. Based on the examination of the placenta (19.8% monochorial) and of genetic makrers, 406 pairs proved to be monozygotic and 645 dizygotic. Sex ratio of twins at birth showed a female preponderance (1000 F: 1009 M) in comparison to singletons (1000 F: 1071 M). Average birthweight of the twins was 2101 g. The frequency of stillbirths was about four times higher in twins than in singletons, twice as high in monozygotic than in dizygotic twins, and 2.4 times higher among second than first-born twins.
布达佩斯双生子登记处记录了1970年至1974年间发生的1739例多胞胎中的88.6%。其中，31.2%为异性双胞胎。通过对胎盘（19.8%为单绒毛膜）和基因标记的检查，证实406对为单卵双胞胎，645对为双卵双胞胎。与单胎（1000名女性：1071名男性）相比，双胞胎出生时的性别比显示女性占优势（1000名女性：1009名男性）。双胞胎的平均出生体重为2101克。双胞胎的死产频率约为单胎的四倍，单卵双胞胎的死产频率是双卵双胞胎的两倍，二胎双胞胎的死产频率比头胎双胞胎高2.4倍。
