Pregnancy benefit for what?

Discovery has a basket of blood tests that they cover during pregnancy. One of them is listed as 'glucose'. So I went for the glucose test that my doctor prescribed. Now suddenly they come back to me to say that they don't really cover the glucose tests that gets done during pregnancy. Discovery, your pregnancy benefit is a joke! first my benefit was randomly cancelled, now I find out that, ONCE AGAIN you don't really cover things. At this point I really don't even know why we have medical insurance. You have caused me so much stress during my pregnancy and made it a horrible experience. How many moms have you **********??