What to Know About Placenta Previa

Understanding Placenta Previa: A Guide to Diagnosis, Management, and Delivery

During pregnancy, the placenta is your baby's lifeline, providing oxygen and nutrients. Normally, it implants high in the uterus, away from the cervix (the opening to the womb). But in the case of placenta previa, the placenta attaches low in the uterus, partially or completely covering the cervix. This condition requires careful management and almost always changes your birth plan.

While a placenta previa diagnosis can be concerning, understanding the condition empowers you to work with your healthcare team for the safest possible outcome for you and your baby.

What is Placenta Previa? The Different Types

The diagnosis and its implications depend on how much of the cervix is covered. There are three main types:

1. Complete or Total Previa: The placenta completely covers the opening of the cervix.

2. Partial Previa: The placenta covers only a part of the cervical opening.

3. Marginal Previa: The placenta is positioned at the very edge of the cervix but does not cover it.

It's also common to hear the term "Low-Lying Placenta," which means the placenta is near the cervix but not covering it. Many low-lying placentas detected early in pregnancy resolve on their own.

Why Does It Happen? Causes and Risk Factors

The exact cause of placenta previa is unknown, but several factors increase the risk:

• Previous Uterine Surgeries: A prior C-section, D&C, or other surgery that created scar tissue on the uterine wall.

• Multiple Pregnancies: Carrying twins, triplets, or more.

• Advanced Maternal Age: Mothers over 35 have a higher risk.

• Multiparity: Having had several previous pregnancies.

• Smoking and Cocaine Use.

• History of Placenta Previa: A previous pregnancy with this condition increases the risk in a subsequent one.

The Primary Symptom: Painless Bleeding

The most classic and significant symptom of placenta previa is sudden, painless, bright red vaginal bleeding in the second or third trimester. This bleeding occurs because as the lower part of the uterus stretches and thins in preparation for labor, it can cause the placenta to separate from the uterine wall, resulting in bleeding.

Important: Not all women with previa will bleed before going into labor, but any bleeding during pregnancy should be reported to your healthcare provider immediately.

How is it Diagnosed and Managed?

Placenta previa is almost always diagnosed during a routine second-trimester anatomy ultrasound (around 18-20 weeks).

Management is focused on getting you as close to your due date as possible while preventing bleeding and preterm labor:

1. Activity Restrictions (Pelvic Rest): This is a critical component. You will be advised to avoid anything that could irritate the cervix or cause bleeding, including:

   • Sexual intercourse

   • Using tampons

   • Douching

   • Strenuous exercise

   • Heavy lifting

2. Possible Bed Rest: If bleeding occurs, you may be put on modified or complete bed rest to reduce pressure on the placenta.

3. Hospitalization: For significant bleeding, hospitalization may be necessary for close monitoring of you and your baby. You may receive medications to help the baby's lungs mature faster in case of early delivery and blood transfusions if needed.

4. Corticosteroids: If delivery before 37 weeks seems likely, you will be given steroid injections to help accelerate your baby's lung development.

The Impact on Your Birth Plan: Delivery by Cesarean Section

For women with a complete or partial placenta previa, a planned C-section is the only safe delivery method. Attempting a vaginal delivery would cause life-threatening hemorrhage for the mother as the placenta would detach before the baby.

The timing of the C-section is typically scheduled around 36 to 37 weeks of pregnancy to avoid the risk of going into labor naturally, which could trigger a dangerous bleeding episode.

For women with a marginal or low-lying placenta, a vaginal birth may still be possible if the placenta is at least 2 centimeters away from the cervix. Your doctor will perform a final ultrasound in the third trimester to check the placenta's position and make the final call.

Looking Forward

A placenta previa diagnosis means your pregnancy will be monitored more closely. It requires adapting your expectations and following your medical team's guidance carefully. While it involves risks and a different path to delivery, with modern obstetric care, the vast majority of women with placenta previa go on to have healthy babies and safe recoveries.

The key is vigilance: report any bleeding immediately, adhere to your activity restrictions, and attend all your prenatal appointments. Your cooperation is the most important factor in navigating this condition successfully.