Had a ultrasound of my ovaries and they saw a cyst 2cm on my left ovary. obgyn said it's normal and that we will do another ultrasound in 3 months. isn't 2cm really big? shouldn't we do a biopsy? worried?

Monthly, a woman's ovaries grow an ovum within a cystlike structure which is eventually released. It is likely that this ovum-cyst will rupture, releasing the ovum and will heal as normal. This is most likely the reason for the Dr's desire to wait. If the cysts persists or enlarges, then the Dr will reevaluate the situation and may recommend further treatment.

A 2 cm cyst is not really big and will most likely resolve spontaneously. A 5 cm or greater cyst would require closer follow up and a cyst 10 cm or more would probably require surgical removal. If your cyst remains stable and its appearance does not otherwise change, it only needs to be periodically monitored.