The placenta develops at the same time as your baby and is attached to the lining of your uterus (womb) during pregnancy.
It allows for oxygen and nutrients to pass from you to your baby as well as producing hormones that support your pregnancy.
Sometimes the placenta develops in the lower part of a woman’s uterus.
If the placenta is covering or partly covering your cervix towards the end of your pregnancy, it will block your baby’s path through your vagina and you’ll have to deliver your baby by caesarean section.
Placenta praevia diagnosis
If your placenta is lying low in your uterus, it may show up in the ultrasound scan that many women have between 18 to 20 weeks of pregnancy. If the scan shows that you may have placenta praevia, you’ll probably be asked to have another scan at about 32 weeks.
For most women, that second scan will show the placenta has naturally moved up as the uterus expanded during pregnancy. Sometimes it moves up between the second scan and the baby’s due date.
Your doctor may find that placenta praevia is the reason a baby is in the breech position or lying across your bump.
Sudden, painless bleeding is another symptom of placenta praevia.
You should have any bleeding during pregnancy checked by your doctor.
Placenta praevia risks and complications
Most women with placenta praevia don’t have any complications, but if there are complications, they can be serious.
They may cause early labour or bleeding that can be dangerous to you and your baby.
Managing placenta praevia
There’s nothing that can be done to move the placenta, you must wait to see if it moves naturally.
Whether you’ve had bleeding or not, your doctor is likely to suggest you have someone nearby to help you at all times, and that you are close to a hospital.
You may be advised not to do strenuous exercise or other activities.
Your doctor may suggest that you go into hospital before the birth, and that you have a caesarean section.
Learn more about placenta praevia treatment on the Pregnancy, Birth and Baby website.
Last reviewed: October 2015