When I had my scan they offered two types, external (on the belly) and internal (a probe) - I ended up having both. Make sure you have a full bladder for the external and you should be fine. The probe isn't painful just more uncomfortable.
My symptoms were that I never had periods, im talking like 1-2 a year if that. Didn't really realize how abnormal it was until I worked in an office full of women and they used to moan about their periods each month. Other than that I didn't have the excess hair, acne or weight problems like other people sometime have (my weight problems came from chocolate & cake

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