lo loestrin/all pill effectiveness?

[helpme11111.livejournal.com]

 Hi all,

Perhaps this question is best posed to a birth control specific community but I love you guys here so perhaps you'll be able to advise me.

I've just recently re-started hbc after a short break. My doctor prescribed the new lo loestrin with the lowest dose of estrogen available. I love it so far.

Anyway, my question is, the insert information for the pill pack says that the average chance of pregnancy while taking the pill is 2-4 women in 100.  This seems very high to me, so I did a search and found on the birthcontrol community a few users who commented that they believe the 2-4 statistics show just one rate of use, and not "perfect use" vs. "typical use" as other warnings use.

In this post it was said that "we think the only thing that's changed is the wording, the actual rates have been the same all along."  BUT the posters are clear that they only "think" this is true, and there is no person with this information for sure.

Naturally, I'm a little worried.  4 in 100 seems high.  I am an example of perfect use (knock on wood!). I take my pill at 8PM ON THE DOT every day.  My old pill (Levora) said that perfect use had a .1% failure rate, and typical use had a 2% failure rate.  Now the only listed rate is 2-4%.  So, forgoing the "there's always a CHANCE and if you're worried you should use a condom" advice, does anyone know anything about this new percentage? Do you think it's a question I should pose to the manufacturers?

Comments

[sweetchild92.livejournal.com]

As was explained to me in birthcontrol the reasoning is that perfect use, to get that 99.7% effectiveness, is usually only achieved in a clinical setting. You're taking it as accurately as possible, which is going to give you more protection, but for many, that perfect use (and for on I admire that because even when I set an alarm I would blatantly forget) is not going to be achievable, and are falling more along the lines of that 2-4% failure rate.

[helpme11111.livejournal.com]

Yes, this is exactly what I thought. But my main problem is that this 2-4% is listed in the same way as the .1% was listed on my last bc insert, and I wondered if anyone has actually asked a doctor, manufacturer, or pharmacist whether this reasoning is correct.

[queensugar.livejournal.com]

Okay, I have a few thoughts on this.

One thing to be aware of is that "perfect use" is theoretical. It's a figure determined by contraceptive researchers, based on various bits of evidence that determine the total likelihood, in a year, of method failure. (I.E. the method itself failing to act properly.) Oral contraceptives have generally had a listed perfect use efficacy rate of 99.8% or so, meaning about 2 women in 1,000 will get pregnant in a year of using just HBC.

"Typical use" -- which is usually pegged at about 92% efficacy in a year for HBC use, or about 8 in 100 women becoming pregnant in a year -- is the data taken from real populations, meaning that that's the number of pregnancies they see in a year in actual populations they have surveyed.

However, "typical use" stats also have their problems. For one, the measurements can be very poor at measuring multiple methods -- i.e. in many surveys, if two methods are used, they only count the most effective method.

On the other hand, with hormonal birth control pills, most pregnancies in the "typical use" surveys occured when pill users stopped taking pills entirely, but did not begin a new method at all. Their pregnancies are still counted against the pill because of the way the surveys work -- even though they weren't using the pill at the time.

One thing I have wondered -- and for the record I have NOT looked into this at all, but we had a discussion in the past -- is the LoEstrin stat actually represents the "typical use" stat minus the pregnancies occured when pill users quit but didn't switch. I ran the numbers once, and it worked out to bump that 92% typical use efficacy up to the 96% to 98% efficacy LoEstrin now names.

Anyway, it would make sense to me, but I can't comment exactly. But it's worth noting for your own understanding that "perfect use" has always been theoretical, and while in some ways "typical use" is more "realistic," it's also itself a highly problematic statistic.

[helpme11111.livejournal.com]

Okay, that makes a lot of sense. So I guess my question is, is lo loestrin any less effective than other low-dose hbc pills because of the 10mg dosage, or is it just a new way of writing dow the statistics?

[queensugar.livejournal.com]

My personal understanding (and again, I haven't looked into this super deeply and fully concede I may be wrong) is that it should not be any less effective, with the caveat that some research I believe has raised the question that low-estrogen pills may be slightly less effective in people of a certain weight or above (I believe its 180 lbs., but I may be wrong), if you might fall into that category -- though the answer to that question is still being debated.