在人类 ,一般一次妊娠仅有一个胎儿 ,多胎是人类妊娠中一种特殊现象 ,当一次妊娠怀有两个或两个以上胎儿称为多胎妊娠。人类的多胎妊娠中以双胎多见 ,三胎少见、四胎和四胎以上罕见。多胎妊娠的早产率、难产率、合并妊娠高血压综合征、产后出血及围生儿死亡率均明显高于单胎妊 In humans, there is usually only one fetus in one pregnancy, and multiple births are a special phenomenon in human pregnancy. When two or more fetuses in one pregnancy are called multiple pregnancies. More common in human multiple pregnancies in twins, rare in three infants, four infants and more than four infants rare. Premature birth rate, refractory rate, pregnancy-induced hypertension syndrome, postpartum hemorrhage and perinatal mortality were significantly higher than those of singleton pregnancy