placenta previa
Abnormal placental implantation where placental tissue covers or lies near the cervical opening.
Full Definition
A condition where the placenta implants in the lower uterine segment, either partially or completely covering the internal cervical os. Classification includes complete previa (placenta completely covers the os), partial previa (placenta partially covers the os), and marginal previa (placental edge reaches the os). This condition occurs in approximately 0.5% of pregnancies and may cause painless vaginal bleeding, particularly in the third trimester. Risk factors include advanced maternal age, multiparity, previous cesarean delivery, and smoking. Management depends on the degree of previa, gestational age, and bleeding severity, often requiring cesarean delivery to prevent hemorrhagic complications.
Usage
Usage note: Specify the type and distance from cervical os when documenting.
In Context
- "Complete placenta previa was diagnosed at 20 weeks, requiring pelvic rest and activity modification." — Maternal-fetal medicine consultation
- "Cesarean delivery was planned for persistent placenta previa at 36 weeks gestation." — Delivery planning documentation