Placenta Previa: Symptoms, Causes, Treatment

What are the symptoms of placenta previa?

Placenta previa is a condition during pregnancy where the placenta partially or completely covers the cervix, the opening to the uterus. The main symptom of placenta previa is painless vaginal bleeding, which typically occurs in the second or third trimester of pregnancy. Other symptoms may include:

1. Painless Vaginal Bleeding: This is the most common symptom and can vary in amount. The bleeding can start suddenly, without warning, and is usually bright red. It often occurs after 20 weeks of pregnancy and can happen repeatedly.
2. Contractions: In some cases, women with placenta previa may experience contractions, though this is less common.
3. Abdominal Pain: While placenta previa typically causes painless bleeding, some women may experience mild cramping or abdominal discomfort.
4. Signs of Preterm Labor: In some cases, symptoms like regular contractions, back pain, and pressure in the pelvis may indicate preterm labor associated with placenta previa.
5. Unusual Fetal Position: During an ultrasound, the baby may be in an unusual position, such as breech or transverse, which can sometimes be associated with placenta previa.

It’s important to note that not all women with placenta previa experience noticeable symptoms. Sometimes the condition is discovered during a routine ultrasound without any symptoms. However, if you experience any vaginal bleeding during pregnancy, it’s crucial to seek immediate medical attention, as it can indicate placenta previa or other complications.

What are the causes of placenta previa?

The exact cause of placenta previa isn’t fully understood, but several factors may increase the risk of developing this condition. These include:

1. Previous Uterine Surgery: Women who have had previous surgeries on the uterus, such as a cesarean section, myomectomy (fibroid removal), or other uterine operations, are at a higher risk of placenta previa.
2. Multiple Pregnancies: Having multiple pregnancies, especially if they are closely spaced, increases the likelihood of placenta previa.
3. Advanced Maternal Age: Women over the age of 35 are at an increased risk for placenta previa.
4. Multiple Gestations: Carrying twins or more can increase the risk of placenta previa.
5. Uterine Abnormalities: Abnormalities in the structure of the uterus, such as a septate uterus or other congenital uterine anomalies, may contribute to placenta previa.
6. Previous Placenta Previa: Having had placenta previa in a previous pregnancy increases the risk of it occurring again.
7. Smoking and Drug Use: Smoking and the use of certain drugs may increase the risk of placenta previa.
8. High Parity: Women who have had many pregnancies are at higher risk for placenta previa.
9. Increased Number of Placental Sites: The presence of multiple placental sites can increase the likelihood of placenta previa.

While these factors can increase the risk, many women with these risk factors do not develop placenta previa, and it can occur in those without any identifiable risk factors. Regular prenatal care and ultrasounds help in early detection and management of this condition.

How is the diagnosis of placenta previa made?

Diagnosing placenta previa typically involves a combination of the following methods:

1. Ultrasound: The primary tool for diagnosing placenta previa is an ultrasound. This imaging technique uses sound waves to create images of the uterus and placenta. A transabdominal ultrasound (performed on the abdomen) is usually the first step, but a transvaginal ultrasound (performed with a probe inserted into the vagina) may be used for a clearer view. The ultrasound can determine the position of the placenta relative to the cervix and whether it is partially or completely covering the cervical opening.
2. Medical History and Symptoms: The diagnosis may be prompted by symptoms such as painless vaginal bleeding in the second or third trimester. A thorough medical history and description of symptoms are important for the diagnosis.
3. Physical Examination: While physical examinations are less definitive for diagnosing placenta previa, they may be used to assess overall health and any associated symptoms. However, digital vaginal examinations are generally avoided in cases of placenta previa due to the risk of causing bleeding.
4. Follow-Up Ultrasound: If placenta previa is detected, follow-up ultrasounds may be scheduled to monitor the placenta’s position as the pregnancy progresses. In some cases, the placenta may move away from the cervix as the uterus expands, which could resolve the condition.

Diagnosis is typically confirmed if the placenta is found to be covering or lying very close to the cervix in these imaging studies. If placenta previa is suspected or diagnosed, management strategies are discussed to ensure the safety of both the mother and the baby.

What is the treatment for placenta previa?

The treatment for placenta previa largely depends on the severity of the condition, the presence of symptoms, and the stage of pregnancy. Here are the main approaches to managing placenta previa:

1. Monitoring and Bed Rest: In cases where placenta previa is diagnosed but there is no significant bleeding or other complications, the management may include close monitoring with regular ultrasounds and sometimes bed rest. This helps to reduce the risk of bleeding and allows for early detection of any changes.
2. Avoiding Vaginal Examinations: To prevent triggering bleeding, vaginal examinations are generally avoided until the placenta has moved away from the cervix or the condition resolves.
3. Medications: In cases of bleeding, medications may be administered to help manage symptoms and control bleeding. For example, medications may be used to help with uterine contractions or to prevent preterm labor.
4. Planned Cesarean Section (C-Section): If placenta previa is diagnosed, especially in the third trimester, a cesarean section is usually planned to avoid the risk of bleeding during a vaginal delivery. The timing of the C-section is typically scheduled between 34 and 37 weeks of gestation to allow for fetal lung maturity while minimizing risks associated with placenta previa.
5. Hysterectomy: In severe cases where the placenta is deeply embedded or if there is significant bleeding that cannot be controlled, a hysterectomy (removal of the uterus) may be performed after the delivery to prevent further complications and control bleeding.
6. Blood Transfusions: Due to the risk of significant bleeding, blood transfusions may be necessary during or after delivery to replace lost blood and manage anemia.
7. Delivery Planning: The delivery plan will involve a multidisciplinary team including obstetricians, anesthesiologists, and neonatologists to manage any complications that arise and ensure the safety of both mother and baby.
8. Postpartum Care: After delivery, the mother will receive close monitoring to manage any residual bleeding or complications. Follow-up care is important to ensure recovery and address any issues.

The specific approach to managing placenta previa is tailored to each individual’s situation, taking into account the gestational age, severity of the placenta previa, and overall health of the mother and baby.