To Denise Parker-- re the data on contraceptive failure-- 0.1% vs 1%-- this
is the old apples and oranges thing.

Contraceptive failure is measured two ways-- ideally, and really.

The doctor was giving the ideal rate, if everything is done absolutely
correctly, how it should be.  Under these cicumstances, estrogen-progestin
combination pills have a theoretical pregnancy rate of 0.1%.

However, in real life-- in actuality, in studies of real women, motivated and
really using it, but living real lives, with all the complications real life
involves, so that there is occasional pill skipping, forgetting, remembering,
taking it different times of day, etc., you get an actual failure rate of 1
to 3%.

This is where the discrepancy comes from.

Failure rates, by the way, are given per year of use, so 0.1% means 1 chance
in a thousand of getting pregnant while using this method for a year, 3%
means 3 chances in a hundred of getting pregnant using the method for a
 year. (They use the term "women-years"-- the number of pregnancies to be
expected in a hundred women-years-- if 100 women took it for one year, ten
women for ten years, 50 women for two years, all of these are a hundred
women-years of contraceptive use. So 0.1% means one pregnancy in a thousand
women-years. 3% means 3 in a 100, or 30 in a thousand.)

I believe that the lactational amenorrhea rate is only measured in real life,
so you've got to compare reality to reality.

Comparing ideal to ideal is often worthless.. For example, abstinence as a
birth control method has an ideal pregnancy rate of 0%, but, among teens, it
has the highest actual failure rate of all methods practiced.  (Among nuns,
the failure rate would be quite a bit better, but still not 0%.)

For discussion and data on this, see Contaceptive Technology, updated yearly,
by Stewart et al. (no data on nuns, and I think there's no data on LAM, altho
I'm not looking at it now-- it's at work.)

--Tina, who has to get back to studying for the IBLCE.