ANALYSIS FOR PERINATAL MORTALITY OF TWIN PREGNANCIES AND SINGLETON PREGNANCY.

Objective:To investigate the influential factors for perinatal mortality of twin pregnancies and singleton pregnancy.Methods:The retrospective analysis included data on a total of 155 twin pregnancies and 10 599-singleton pregnancy delivered at the Department from 1989 to 1998.Results:Excluding congenital deformities,the total perinatal mortality of twin preganancies was significantly higher than that of singleton pregnancy(χ~2=94.71,P0.001).Perinatal mortality of twin pregnancies in ≥37 gestational weeks group and 32 to 36~(+6) gestational weeks group were significantly higher than that of singleton pregnancy(χ~2=9.85,P0.01;χ~2=7.61,P0.01,respectively),however,in32 gestational weeks group the result was reverse(χ~2=12.93,P0.0001).Perinatal mortality of twin pregnancies in ≥2 500 g birth weight group was significantly higher than that of singleton pregnancy,but in 1 500～g and 1 500 g birth weight group,their mortality had no significantly difference(χ~2=0.182,P0.05;χ~2=1.536,P0.05,respectively).Perinatal mortality of twin and singleton pregnancy decreased with gestational weeks and birth weight increasing.Conclusions:Perinatal mortality is markedly influenced by gestational weeks and birth weight.Compared with singleton pregnancy,twin pregnancies have their own characteristics.Further studies are necessary to investigate the standard of suitable gestational weeks and birth weight for twin pregnancies.