How effective is growth scan for placenta praevia?

Ultrasound can measure the baby's growth, assess amniotic fluid and show where the placenta lies in relation to the cervix. As pregnancy progresses, the apparent position may change as the uterus grows, so a later assessment may be arranged when clinically appropriate.

The scan is not a test that predicts whether bleeding will occur. It may not answer every question about the safest route or timing of birth, and the view can depend on fetal position and imaging conditions. Your maternity team uses the report with bleeding history and examination findings.

Attend the recommended follow-up scan and ask whether the placenta remains close to or covers the cervix. Follow your team's instructions about activity, intercourse, travel and where to attend if bleeding starts; these recommendations depend on your findings and history.

Do not wait for a scheduled growth scan to report bleeding. Ask how the placental position affects birth planning, whether another type of ultrasound is needed, and which clinicians should review your report. Read more about [Growth Scan](/treatments/pregnancy-and-birth-care/growth-scan/).

Any vaginal bleeding in pregnancy with known or suspected placenta praevia needs urgent contact with your maternity unit, even if it is light or painless. Call emergency services for heavy bleeding, dizziness, fainting, severe pain or feeling unwell. Also seek urgent advice for leaking fluid or regular contractions.

Ask where the placental edge is in relation to the cervix, whether the scan view is clear, and when position should be checked again. Clarify the hospital plan for bleeding, whether vaginal examinations should be avoided until assessment, and how the findings influence birth planning.