Placenta Previa Diagnosis and Treatment

There are three types of placenta previa.

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During pregnancy, the placenta normally attaches to the upper part of the uterus, away from the cervix. With placenta previa, the placenta attaches low within the uterus, covering all or part of the cervix.

This can be problematic later on in pregnancy, as it may cause severe bleeding, leading to a preterm delivery.

Types of Placenta Previa

  • Complete previa: the cervical opening (where the cervix opens into the uterus) is completely covered by the placenta
  • Partial previa: some of the cervical opening is covered by the placenta
  • Marginal previa: the placenta extends to edge of the cervix (so close by but not covering)

Risk Factors

There are a number of potential factors that may increase a woman's chance of having a placenta previa. Remember, your chance of having a placenta previa is still low (about 1 in 200 women in the third trimester), though it does increase if you have one or more of these risk factors:

  • Previous placenta previa
  • Advanced maternal age
  • Increased parity (number of pregnancies)
  • Being pregnant with more than one baby (for example, twins or triplets)
  • Previous uterine surgery, including cesarean section (regardless of incision type) or a D&C
  • Prior abortion
  • Infertility treatment
  • Smoke cigarettes
  • Cocaine use


During a second trimester ultrasound (done in many places on a routine basis around the 20th week), some women will get a diagnosis of placenta previa. The good news is that the majority of these placenta previas resolve on their own.

Other women may receive a diagnosis of placenta previa when they begin experiencing painless bleeding from their vagina during the third trimester. That being said, it's important to note that not all women with placenta previa experience bleeding. In addition to vaginal bleeding, some women also experience premature uterine contractions.

Complications for Mother and Baby

True placenta previa at full term is serious for both the mother and baby.

Complications for Baby

Some potential complications for the baby include:

  • Health problems for the baby, requiring a NICU admission
  • Preterm birth 
  • Intrauterine growth restriction (IUGR) due to poor placental perfusion
  • Increased risk of perinatal/neonatal death (stillbirth or babies who die within one week to one month of life).

This increased risk of perinatal or neonatal death is a result of babies being born early.

Complications for Mother

For mothers in advanced countries like the United States, placenta previa is rarely fatal. That being said, bleeding may occur prior to, during, or after labor and delivery. Sometimes, a woman may require blood transfusions for severe, life-threatening bleeding. 

Other potential risks for a mother from having placenta previa include:

  • Preterm labor and premature rupture of membranes
  • Need for a cesarean delivery (this is common)
  • Increased risk of placenta accreta (this is when the placenta attaches directly to the uterine muscle)

Treatment for Placenta Previa in the Third Trimester

If you have persistent placenta previa in the third trimester, your doctor may advise that you avoid sex, strenuous exercise, and using tampons. A doctor may also recommend bed rest, frequently in the hospital. Depending on the gestational age, steroid shots may be given to help mature the baby's lungs.

If the placenta previa does not resolve by the third trimester, a cesarean delivery will nearly always be performed. In addition, if at any time, the bleeding cannot be controlled, an immediate cesarean delivery is needed. 

A Word From Verywell

Placenta previa can be a stressful diagnosis for all involved. The period of time from the diagnosis to the delivery are often periods of great worry and fear. The good news is that there are support groups for those who have been diagnosed with placenta previa, and/or who are under bed rest orders.

Be sure to reach out to your doctor if you experience any vaginal bleeding during pregnancy, or if you have any questions or concerns related to your placenta previa or pregnancy in general. 

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Article Sources
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  1. Kollmann M, Gaulhofer J, Lang U, Klaritsch P. Placenta praevia: incidence, risk factors and outcome. J Matern Fetal Neonatal Med. 2016;29(9):1395-1398. doi:10.3109/14767058.2015.1049152

  2. Jauniaux E, Alfirevic Z, Bhide AG, et al. Placenta Praevia and Placenta Accreta: Diagnosis and Management: Green-top Guideline No. 27a. BJOG. 2019;126(1):e1-e48. doi:10.1111/1471-0528.15306

  3. Zlatnik MG, Little SE, Kohli P, Kaimal AJ, Stotland NE, Caughey AB. When Should Women With Placenta Previa Be Delivered? A Decision Analysis. J Reprod Med. 2010;55(9-10):373-381.

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