Placenta previa is generally defined as the implantation of the placenta over or near the internal os of the cervix after 28 Gestational weeks.是什么意思_Placenta previa is generally defined as the implantation of the placenta over or near the internal os of the cervix after 28 Gestational weeks.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句