Unexplainable Demographic Phenomena of Multiple Births in Hungary

Abstract

The decrease trend of multiple births temporarily broke off in Hungary in 1970, with an increase from 18.18‰ (1968) to 20.94‰ (1970), i.e., about 400 cases of excess.The male preponderance in twin births is lower than in single births, and triplets actually show a female excess.There are more boys than girls among the first-born of multiple births.According to the 1959 and 1968 figures, both DZ and MZ twin births were significantly more frequent in mothers aged 16 or less than in mothers aged 17-19 years.The monthly distribution of DZ twins is characteristic, while the monochorial MZ twins did not show seasonal variations.