Mortality Rate of Japanese Twins and Triplets II. Socioeconomic Factors Influencing Infant Deaths of Twins After Birth to One Year of Age

Abstract

The rates of infant mortality of twin individuals were 4.38% and 7.76% for mothers healthy and nonhealthy after delivery, respectively, and the difference is significant at the 0.01 level. The lowest infant mortality rate was seen in the mothers with paid work during pregnancy (4.56%), followed by the mothers engaged only in housekeeping (4.72%) and by those self-employed during the pregnancy (4.99%). Infant mortality rate for MZ twins decreased with increased monthly expenditure of the household, whereas the rate for DZ twins remained constant with expenditure. Socioeconomic factors still affect the infant mortality of twins, and the infant mortality rate can be improved.