I get ovarian cysts quite often but they usually resolve themselves after a few months. I usually don;t go until after about 4mths. I have never heard of getting them removed, my last one was over 10cm but they just kept me on monthly scans until it disappeared. But I have heard they can be dangerous if they burst or they can contort the ovary/tube. I would go and get it checked if you are worried.

I find mine are usually quite while breastfeeding but flare up again afterwards like now :-)