How many millimeters is the normal value for the lower margin of the placenta from the internal os of the cervix?

Patient's question:

No

Doctor's answer:

Hello, this condition is currently referred to as placenta previa. It will gradually move upwards as the gestational age progresses. It is important to have regular follow-up examinations because the lower position may lead to bleeding, and sexual activity and strenuous exercise should be avoided.