正常妊娠时,胎盘附着在子宫体的前壁、后壁和侧壁上,如果胎盘附着在子宫下段、或直接覆盖在子宫颈内口上,则称为前置胎盘。这种病的发病率比较高,大约每200～400名孕妇就有一例前置胎盘的患者,尤其是高龄经产妇的发病更多些。前置胎盘是妊娠晚期阴道出血的重要原因之一,对胎儿、孕妇及分娩影响都很大。一、前置胎盘的分类 Normal pregnancy, the placenta attached to the anterior wall of the uterus, posterior wall and sidewall, if the placenta attached to the lower uterine segment, or directly covered in the mouth of the cervix, then called the placenta previa. The incidence of this disease is relatively high, about every 200 to 400 pregnant women have a case of placenta previa patients, especially older women by the incidence of more. Placenta previa is one of the important reasons for vaginal bleeding in late pregnancy, the fetus, pregnant women and childbirth are great. First, the classification of placenta previa