Understanding Placenta Praevia, Placenta Accreta, and Vasa Praevia

During pregnancy, the placenta is a vital organ, providing your baby with oxygen and essential nutrients through a connection to your bloodstream. Occasionally, however, complications such as placenta praevia, placenta accreta, and vasa praevia can occur, potentially affecting your health and the safety of your baby. In recognition of Cesarean Awareness Month, we’re highlighting these important conditions, ensuring you’re informed and prepared.

What is Placenta Praevia?

Placenta praevia occurs when the placenta attaches low in the uterus, sometimes partially or completely covering the cervix (the entrance to the womb). Normally, as pregnancy progresses, the placenta moves upward, but in some cases, it remains low-lying. If the placenta stays within 20 mm of the cervix, it’s called a low-lying placenta. If it completely covers the cervix, it’s known as placenta praevia.

Who is at Risk? Placenta praevia is more common among women who have had previous cesarean births, fertility treatments, or those who smoke.

Risks and Symptoms Placenta praevia can cause significant vaginal bleeding, particularly in the later stages of pregnancy. This bleeding is typically painless but can be heavy and may threaten both mother and baby. It can also mean your baby needs to be delivered by cesarean, as the placenta can block the birth canal.

Diagnosis and Care Placenta praevia is usually identified during the routine 20-week ultrasound. Follow-up scans at 32 and possibly 36 weeks will monitor its position. If confirmed, additional measures such as steroid injections to mature your baby’s lungs, medication to delay premature labour, and potential hospitalisation to manage risks might be recommended.

Birth Considerations If placenta praevia remains close to or covering your cervix by 36 weeks, a planned cesarean between 36-37 weeks is advised. Special preparations, including having senior medical professionals and blood transfusions available, are typically arranged.

What is Placenta Accreta?

Placenta accreta is a rare but serious condition where the placenta grows deeply into the uterine wall muscle, complicating its removal after birth. Occurring between 1 in 300 and 1 in 2,000 pregnancies, it’s more common in women with placenta praevia who’ve had previous cesareans, uterine surgeries, fertility treatments, or are older mothers.

Risks and Symptoms Placenta accreta can lead to severe bleeding at delivery, often necessitating a hysterectomy (removal of the uterus) to control blood loss. There is also an increased risk of bladder injury during birth.

Diagnosis and Care Placenta accreta might be identified through ultrasound and possibly MRI during pregnancy, though final confirmation is often at delivery. Birth is typically scheduled early (between 35-37 weeks) in a specialist centre with experienced medical teams available. Options discussed might include a planned cesarean hysterectomy or, in some cases, leaving the placenta in place, though the latter carries additional risks.

What is Vasa Praevia?

Vasa praevia is an extremely rare condition (affecting between 1 in 1,200 and 1 in 5,000 pregnancies), where fetal blood vessels cross the cervix without protection from the placenta or umbilical cord. These vessels can easily rupture when labour begins or waters break, putting your baby’s life in serious danger due to rapid blood loss.

Risks and Symptoms If vasa praevia is not identified early, sudden heavy bleeding from the baby’s vessels can occur during labour or water breaking, significantly risking the baby’s life.

Diagnosis and Care Risk factors include low-lying placentas, multiple pregnancies, and abnormal placenta or cord development. Additional ultrasound scans may identify vasa praevia during pregnancy. If confirmed, a planned cesarean is recommended between 34-36 weeks, alongside steroid injections to assist your baby’s lung maturity.

Empowering Your Choices

If you’re diagnosed with placenta praevia, placenta accreta, or vasa praevia, it’s essential to discuss your options thoroughly with your healthcare team. Remember to ask:

• What are my options?
• What are the benefits and risks?
• What support is available to help me decide?

Being well-informed and prepared helps ensure the best outcomes for you and your baby. For more detailed information and support, consult with your healthcare provider and trusted resources like MAMA Academy, the RCOG, NCT, and Tommy’s.