Cheryl Roth, a nurse practitioner at HonorHealth's Labor & Delivery unit at HonorHealth Scottsdale Shea Medical Center, answers questions about placenta previa. It's one of the many reasons why prenatal care is so critical for the health of you and your baby.
Q. What is placenta previa?
A: When you're pregnant, a placenta begins growing on the upper inside wall of your uterus soon after conception. This is how your growing fetus will get necessary oxygen and nutrients. Sometimes the placenta begins growing on the bottom of the uterus, and can completely or partially block the opening to your vagina – your cervix. If the placenta completely blocks your cervix, it's called placenta previa. If it's partially blocking the cervix, it's called partial or marginal placenta previa.
Q. Why is placenta previa a concern?
A: If your cervix is completely blocked, it's not possible for you to deliver your baby vaginally. A C-section will be necessary for the safety of you and your baby.
Q. How is placenta previa diagnosed?
A: Typically, your OB/GYN will detect placenta previa on an 18- to 20-week routine ultrasound. Placenta previa may also be diagnosed by ultrasound if you're experiencing any painless bleeding. Typically bright red, the bleeding can be light (spotting) or quite heavy.
Q. What happens if I'm diagnosed with placenta previa?
A: Your OB/GYN may prescribe pelvic rest, which means nothing can go in the vagina. This includes avoiding sexual intercourse. If you have an episode of bleeding in the latter half of pregnancy, you'll probably be admitted to the hospital for up to a week because of the likelihood of subsequent bleeding, which could be life-threatening for you and your baby. If vaginal bleeding continues to occur, you may be hospitalized until it's safe to deliver your baby by C-section.
Q. What causes placenta previa? Can you prevent it?
A: Although the cause of placenta previa is unknown, it occurs more frequently in women who have had a previous C-section or uterine surgery. The more C-sections you've had, the higher the risk. There's no known way to prevent placenta previa. If you do have it, future pregnancies are more likely to have placenta previa. More severe forms of placenta previa do occur, which may require hysterectomy at the time of delivery.
Q. Can placenta previa resolve on its own?
A: It can, especially if your cervix is only partially blocked. As the uterus grows, the placenta can move away from your vaginal opening. Close supervision of your pregnancy by your OB/GYN will be necessary.