Low-lying placenta

The placenta is located low in the uterus and may be close to or slightly cover the cervix. In many cases, it moves upward as pregnancy progresses. Monitoring is needed to avoid delivery complications. In most cases, the placenta moves upwards and out of the way as the uterus grows during pregnancy. For some women, however, the placenta continues to lie in the lower part of the uterus as the pregnancy progresses. This condition is known as low-lying placenta, where the placenta is less than 20 mm from the cervix, or as placenta praevia if the placenta completely covers the cervix. Having a low-lying placenta at 20 weeks means you need to have a repeat ultrasound at 32 weeks to check the placental site again. 

However it is very important that, if you experience any vaginal bleeding, contractions or pain you should contact the hospital straight away If the placenta remains low-lying, you will have an additional scan at 36 weeks. If the placenta remains low at 36 weeks then you will see an obstetrician who will to decide the safest way to deliver the baby.