Because the outer sex organs appear normal, it is often not found until around age 15, when a young girl notes that she has not had her period and seeks medical care. The diagnosis is made by physical exam and imaging. An ultrasound may be used to check the womb and ovaries. If needed, MRI can show a fuller picture of the reproductive tract.
Most girls do not know about this issue until their teen years. But some cases will be found during infancy, often during an exam or test for other problems.