Cycles with an IUD

[paperstar19.livejournal.com]

I know the periods you get when taking HBC pills are not real periods at all, but progesterone withdrawal bleeding. I know that a "real" period only happens after you've ovulated. I have a Mirena IUD which give me a small, constant dose of progesterone. This means I never have an off week; I've been getting the same amount of hormones everyday for the last three years. Still, I have a (very short and pretty irregular) period. Why? Am I still ovulating? If so, how am I being protected against pregnancy? If I am not ovulating, what is causing my "periods"?

P.S. There is no cause for concern here, I am just super curious.

EDIT: If I am likely ovulating, and I wanted to chart my cycles as if I were practicing FAM (just for curiosity's sake, mainly), would the progesterone muck too my with my symptoms? I assume I won't have the normal pattern of cervical fluid, but will I see the BBT hike after I ovulate?

Comments

[sarahbear1.livejournal.com]

maybe the lining builds up until it can't anymore and then sheds sporadically. That's the only thing I can think of.

Re: How the IUD 'works' its magic =)

[paperstar19.livejournal.com]

I feel like I should have known that, considering I've had the thing in me for 3 years.

[h0rsegurrrl.livejournal.com]

Mirena doesn't have a high enough dose of hormones to stop ovulation in most people. So you probably are still ovulating. A lot of people with Mirena, even those who don't get periods, may still have a "bloodless" cycle, with other period symptoms but no bleeding or very slight bleeding.

The Mirena works by thickening the cervical mucus to make it difficult for sperm to get through, and also makes the uterus hostile to sperm and eggs. It also thins the uterine lining possibly making implantation difficult in the unlikely event that an egg gets fertilized.

[frolicnaked.livejournal.com]

Am I still ovulating?

Statistically, Mirena users ovulate about 40% of the time in their first year with the IUD in place; at the 4th year, about 70% of cycles are ovulatory.

If I am not ovulating, what is causing my "periods"?

For those times where your bleeds are anovulatory, it's pretty much breakthrough bleeding. (This can happen with anovulatory cycles for folks who aren't on any HBC, too.) Eventually, the uterine lining gets built up enough -- or hangs around long enough -- that the body just finally goes, "Um... okay. You. Out now."

[h0rsegurrrl.livejournal.com]

Yes, you can still do FAM charting with Mirena. You're right that it probably makes cervical mucus pattern inaccurate, but I'm fairly certain you'll still have the BBT hike after ovulation, so in that way it should be accurate.