Placenta Praevia: What It Means for Your Pregnancy

How it is discovered

Placenta praevia is almost always found during your anomaly scan at 18 to 21 weeks. At this stage, a low-lying placenta is quite common. As the uterus expands during the third trimester, the placenta is usually carried upward. In the majority of cases, a low placenta at 20 weeks is no longer low by delivery.

If your placenta is low at 20 weeks, you will be offered a follow-up scan at around 32 weeks.

Types of placenta praevia

Minor (low-lying) means the placenta is in the lower uterus but not covering the cervix. Major means the placenta partially or completely covers the cervix.

A minor low-lying placenta may still allow vaginal birth. Major placenta praevia means the baby cannot be delivered vaginally, and a caesarean will be recommended.

Symptoms to watch for

The main symptom is painless vaginal bleeding in the second or third trimester. If you experience any vaginal bleeding after 20 weeks, contact your maternity unit immediately. Some people have no bleeding at all.

How it is managed

If your placenta remains low in the third trimester, you will have additional scans, may be advised to avoid penetrative intercourse, and will be offered a planned caesarean section, usually between 36 and 37 weeks for major placenta praevia, or 38 to 39 weeks for a low-lying placenta close to the cervix.

If you are Rhesus negative and experience bleeding, you will need anti-D injections.

Emotional impact

Being told your placenta is in an unusual position can feel unsettling. In most cases a low placenta at 20 weeks resolves on its own, and even when it does not, a planned caesarean with a specialist team is a safe and well-managed way to deliver your baby.