已有许多妊娠期阴道出血伴胎儿Down综合征发生率高的报告。Ingalls及其同事1957年研究了52例Down综合征妊娠和52例与同年龄孕妇配对的对照组的产科记录,分别在10例病人(19%)和5例对照组(9.6%)有妊娠早期出血,Down综合征出血相对危险率是2.2。Boue等人于80年代收集了46例Down综合征和74例母亲的年龄及孕龄类似的未受累妊娠,由于母亲年龄增加而行羊水穿刺术 There have been many reports of gestational vaginal bleeding with a high incidence of fetal Down syndrome. In 1957, Ingalls and colleagues studied the obstetric records of 52 pregnant women with Down syndrome and 52 matched controls of the same age, in 10 patients (19%) and 5 controls (9.6%) with early gestational age Bleeding, Down syndrome, the relative risk of bleeding is 2.2. Boue et al. Collected 46 cases of Down syndrome and 74 unrelated pregnancies of similar age and gestational age in the 1980s. Amniocentesis was performed due to increased age of mothers