Incidence of twin births among the Chinese in Taiwan

The incidence of twin births in Taiwan is 1:166.4, while that in the National Taiwan University Hospital is 1:80.1. The incidence of twin births in Taiwan is quite similar to that in Japan and much lower than that of the Caucasian and Negro races. The ratio of monozygotic twinning to dizygotic twinning in Taiwan is about 2:1, contrary to the 1:2 seen in the Caucasians. The incidence of dizygotic but not monozygotic twinning is affected by age and parity of the mother. A higher incidence of monozygotic twinning in blood type O mothers and a very high incidence in AB mothers and a low incidence in B mothers of dizygotic twinning are observed.