Placenta Previa
EDP column by Dr Ketan Dhatariya

“I am pregnant and had a small bleed. After my scan I was told I have a ‘placenta previa’. What is this?"

The placenta is the part of the developing baby that allows transfer of energy and oxygen to be delivered to the baby and to allow the removal of waste products from the baby. Because it has to work very hard, the placenta has an extensive blood supply. The baby is attached to the placenta by the umbilical cord.

The placenta can be attached anywhere on the inside of the uterus. Normally the placenta causes no problems, and is safely out of the way until the baby is born. The placenta is then delivered a few minutes after the baby. Placenta previa is where the placenta lies over the inside of the cervix. The cervix is the neck of the womb between the vagina and the uterus. It is where the baby comes out from.

Often the placenta moves upwards during pregnancy. As the uterus gets bigger, the placenta moves off the cervix and uncovers it, ensuring that no problems arise as a result. However, in about 1 in 200 pregnancies the placenta can remain over the cervix. It could be ‘low lying’, where the placenta lies in the lower part of the uterus, but does not touch the neck of the womb, or it could completely covering the opening, or anywhere in between. If the placenta is in the way, then this can cause problems for the baby and for the mother. It can come to light either during an ultrasound scan, or it can cause bleeding during the pregnancy. This bleeding tends to be bright red and painless. If this bleeding occurs, you should contact your doctor quickly. Usually things will settled down without any problems, but very occasionally you or the baby may need help.

If all has stayed well during the pregnancy, and depending on where the placenta is at the end of your pregnancy, your midwife or doctor will discuss the options with you. They may let you have a ‘trial of labour’, or if the placenta lies directly over the opening, then they would probably advise you to have a caesarean section.

As always, if you do not understand something that your doctor or midwife has told you, then ask them to explain it to you in a way that you do understand.