Placenta Previa: Types, Signs, and Risks

As joyous as pregnancy can be, it can also come with its share of challenges and uncertainties. One such challenge that some expectant mothers may encounter is placenta previa, which is a condition that may affect pregnant women as early as 20 weeks into the pregnancy. While it may sound intimidating at first, it isn’t uncommon. According to the March of Dimes, this condition occurs in approximately 1 in 200 pregnancies and may resolve on its own as the weeks progress. Nearly 90% of placentas identified as “low lying” will ultimately resolve by third semester due to placental migration[1]. However, it is serious when it doesn’t resolve which is why it is important to understand this condition, including its symptoms, causes, concerns, and treatment options. 

What is Placenta Previa?

At the beginning of a pregnancy, it isn’t uncommon for the placenta to be low in the womb. As the pregnancy progresses, the placenta gravitates toward the top of the womb, which leaves the cervix open for delivery. Placenta previa happens when the placenta partially or completely covers the cervix and may lead to complications during pregnancy and childbirth.

Types placenta previa marginal, partial, complete

Placenta previa manifests in three primary types: marginal, partial, and complete. In the case of marginal placenta previa, the placenta's edge extends to the edge of the cervix. A portion of cervix is covered in the case of partial placenta previa. Complete placenta previa is when the placenta fully covers the opening of the cervix. This condition poses a risk for postpartum hemorrhaging and a cesarean delivery is required when the mother has placenta previa.

What are the Signs and Symptoms of Placenta Previa?

The most prominent and concerning sign of placenta previa is the unexpected onset of vaginal bleeding, which may be accompanied by cramps or discomfort. The bleeding can range from mild spotting to heavy hemorrhaging. It is crucial not to dismiss any degree of bleeding during pregnancy. Even if it appears to be minor, it should never be taken lightly and warrants immediate medical attention.
In addition to vaginal bleeding, other signs and symptoms of placenta previa may include:
Abdominal discomfort: While not always present, some individuals with placenta previa may experience mild to moderate abdominal discomfort or pain.
Uterine contractions: In some cases, placenta previa can trigger uterine contractions, which may be mistaken for normal pregnancy discomfort.
Fetal distress: The baby may show signs of distress, such as an abnormal heart rate or reduced fetal movement. This can be an indirect indication of placenta previa.

What Causes Placenta Previa?

While the exact cause of placenta previa isn’t clear, understanding both the potential causes and risk factors provides an idea of who may be at risk. It may be connected to several key factors, including:
Placental Positioning: The location of the placenta within the uterus plays a significant role in placenta previa. In cases where the placenta attaches to the lower portion of the uterus, closer to the cervix, the risk of placenta previa increases.
Uterine Shape: An unusually shaped uterus, whether congenital or due to factors such as fibroids, can contribute to placenta previa. These irregular uterine shapes can disrupt the normal implantation of the placenta.
Uterine Scarring: Scar tissue within the uterine cavity resulting from prior surgeries or procedures, such as a previous cesarean section or dilation and curettage (D&C), can elevate the risk of placenta previa. These scars may alter the ability of the uterus to accommodate the placenta properly.

What are the Risk Factors for Developing Placenta Previa?

Placenta Previa Risk Factors

Certain factors can heighten an individual's susceptibility to placenta previa. These include:

  • Advanced Maternal Age
  • Previous Placenta Previa
  • Multiple Pregnancies
  • Previous Cesarean Sections
  • Smoking During Pregnancy
  • In Vitro Fertilization (IVF)


Advanced Maternal Age: Women who become pregnant at an older age, typically defined as over 35 years, face a higher risk of placenta previa.
Previous Placenta Previa: If a woman had placenta previa in a previous pregnancy, the likelihood of experiencing it again in subsequent pregnancies increases. Multiple Pregnancies: Carrying twins, triplets, or more multiples elevates the risk due to the increased demands on the uterine cavity and placental positioning.
Previous Cesarean Sections: A history of cesarean sections can lead to uterine scarring, potentially raising the risk of placenta previa in future pregnancies.
Smoking During Pregnancy: Smoking is a known risk factor for placenta previa. Expectant mothers who smoke should consider cessation programs to reduce this risk.
In Vitro Fertilization (IVF): The use of assisted reproductive technologies, such as IVF, has been associated with an increased likelihood of placenta previa. Close monitoring is crucial for women who conceive through IVF.
If you fall into one or more of these risk categories, it is essential to communicate openly with your healthcare provider, who can tailor your prenatal care and take the necessary precautions.

How is Placenta Previa Diagnosed?


Ultrasound imaging is the primary method for diagnosis and provides valuable information including:
Location and Extent: It helps to pinpoint the location of the placenta within the uterus and assess the extent to which it may be covering the cervix. This information is vital in determining the type and severity of placenta previa.
Fetal Well-Being: It assesses and monitors the baby's development, ensuring that the placental position does not hinder proper fetal nourishment.
Treatment Planning: The information from the images provides a foundation for a tailored treatment plan. Depending on the type and severity of placenta previa, treatment options and recommendations vary.
However, in cases where there is uncertainty or the need for a more detailed evaluation, your healthcare provider may recommend a transvaginal ultrasound. A transvaginal ultrasound is a specialized imaging procedure that provides a more detailed and precise view of the uterus and placental location. It involves inserting a small ultrasound probe into the vagina, allowing for a close-up examination of the cervix and placental positioning.

What are the Complications of Placenta Previa for Mother and Baby?

Placenta previa can pose risks to both the mother and the baby and requires close attention and careful management due to the potential complications it can introduce.

Placenta Previa Complications for Mother and Baby
  • Premature Labor or Delivery
  • Hemorrhaging (Severe Bleeding)
  • Emergency Cesarean Section
  • Shock Due to Rapid Blood Loss
  • Fetal Distress
  • Fetal Growth Problems
  • Pre-term Birth Complications


Risks to the Mother

Premature Labor or Delivery: Placenta previa can lead to premature contractions and labor, necessitating an early delivery. Premature birth poses various challenges, including potential health issues for the baby.
Hemorrhaging (Severe Bleeding): One of the most concerning complications is hemorrhaging or excessive bleeding. The placenta's abnormal positioning can disrupt blood vessels, leading to significant and potentially life-threatening blood loss.

Emergency Cesarean Section: In cases of severe placenta previa or if bleeding becomes uncontrollable, an emergency cesarean section (C-section) may be required. This surgical intervention aims to protect both the mother and the baby.
Shock Due to Rapid Blood Loss: Severe bleeding can result in shock, a medical emergency characterized by low blood pressure and inadequate blood flow to vital organs. Prompt intervention is critical to stabilize the mother's condition.

Risks to the Baby

Fetal Distress: Placenta previa can compromise the baby's access to oxygen and vital nutrients due to the disruption in blood flow caused by bleeding. This can lead to fetal distress, characterized by abnormal heart rate patterns. Monitoring fetal well-being becomes paramount in such cases.
Fetal Growth Problems: Insufficient oxygen and nutrient supply to the developing fetus can hinder proper growth and development resulting in low birth weight.
Pre-term Birth Complications: Babies born prematurely may face a range of health challenges, including respiratory distress syndrome, jaundice, and an increased risk of infections. They may require specialized medical care in the neonatal unit.

What are the Treatment and Management Options?

The treatment and management of placenta previa depend on several factors, including the type and severity of the condition, the gestational age of the fetus, and the mother's health. Treatment options may include:
Bed rest: Resting and limiting physical activity can help reduce stress on the placenta and minimize the likelihood of bleeding episodes. Bed rest may be prescribed in the hospital or at home, depending on the severity of the condition.
Medications to prevent preterm labor: Preterm labor is a concern with placenta previa, and medications may be administered to delay labor and extend the pregnancy. These medications can include tocolytics, which help relax the uterine muscles, and corticosteroids to promote fetal lung development in case of premature delivery.
Blood transfusions: In cases with severe bleeding, blood transfusions may be necessary to replace lost blood and stabilize the mother's condition. This intervention aims to prevent anemia, shock, and other complications resulting from significant blood loss.
Hospitalization: Depending on the type and severity of placenta previa and the mother's condition, hospitalization may be recommended. In a hospital setting, healthcare professionals can closely monitor the mother and baby, ensuring prompt intervention if complications arise.

Are there Necessary Lifestyle Modifications and Precautions?

Managing placenta previa involves not only medical interventions but also specific lifestyle modifications and precautions to safeguard both the mother and the developing baby. Typically, healthcare professionals prescribe the following:
Avoidance of Sexual Intercourse: Engaging in sexual intercourse can pose a risk of vaginal bleeding. To minimize this risk, healthcare providers usually advise expectant mothers with placenta previa to abstain from sexual activity during their pregnancy.
Refraining from Heavy Lifting: Heavy lifting or strenuous physical activities can place excessive pressure on the uterus and potentially trigger bleeding. It is crucial for pregnant individuals with placenta previa to avoid heavy lifting to reduce the risk of complications.
Refraining from Strenuous Activities: Refraining from strenuous activities that could lead to physical exertion or strain is also recommended. This includes activities that involve significant physical effort or sudden movements.

Are there Ways to Prevent Placenta Previa in Future Pregnancies?

If you've experienced placenta previa in a previous pregnancy, it's natural to be concerned about the possibility of recurrence in future pregnancies. While some risk factors are beyond your control, there are steps you can take in collaboration with your healthcare provider to mitigate your risk and promote a safer pregnancy:
Consult with Your Healthcare Provider: Begin by discussing your previous experience with placenta previa with your healthcare provider. They can provide personalized guidance based on your medical history and risk factors.
Address Modifiable Risk Factors: Placenta previa is associated with certain risk factors, some of which can be modified. These may include smoking during pregnancy or other lifestyle factors. Quitting smoking and adopting a healthy lifestyle can reduce your risk.
Plan Your Pregnancy Timing: If possible, consider the timing of your pregnancies. A shorter interval between pregnancies may increase the risk of placenta previa. Planning a longer gap between pregnancies can be beneficial.
Prioritize Prenatal Care: Attending regular prenatal care appointments is crucial in monitoring your pregnancy's progress and addressing any potential issues early on. Regular check-ups allow healthcare providers to identify and manage placenta previa promptly if it recurs.

While placenta previa can pose challenges in pregnancy, proactive measures, and collaboration with your healthcare team can significantly reduce the risk of recurrence in future pregnancies. By addressing modifiable risk factors and staying vigilant through regular prenatal care, you can work toward a safer and healthier pregnancy experience for both you and your baby. If you suspect you may have placenta previa or have concerns about your pregnancy, reach out to your healthcare provider immediately.

Medical Disclaimer: The information provided should not be used for diagnosing or treating a health problem or disease, and those seeking personal medical advice should consult with a licensed physician.

Last Updated on: 04/15/2024 by Diane Paradise