Do I need to stop taking birth control before gettting an FSH LH blood test?

Dear Ask The Doctor: I was prescribed birth control, and I've taken two pills. Do I need to stop before getting the FSH LH blood test? My gynecologist is checking for PCOS. She didn't say anything about not starting the pill until after the test, but I was doing a little research and it seems like I need to stop taking them so the FSH and LH levels will be my own and not altered because of the pill. I'm taking Lo Loestrin Fe.

Dear Elizabeth: OCP's contain estrogen and progesterone and thus can essentially affect the level of FSH and LH in the body through something called a feedback mechanism. Thus it is advisable that you stop taking your OCP's some days prior to taking the blood test. All the best.