Is my wife’s position of placenta normal?

Question
My 35 years old wife is in her 21st week of pregnancy. She underwent a scan, which showed the placenta positioned 4 cm from cervical opening. The doctor told us that the normal distance should be 5 cm. Is the position of placenta normal?
Expert Answer
S
The location of the placenta is well away from the opening and this should not pose a problem at all. As she is only 21 weeks pregnant further migration upwards will occur and there is no cause for worry.