I have never understood my colleagues' agreement to give combination birth
control pills to breastfeeding mothers, because "only some women have a
decrease in milk supply."  We're not talking about giving a cancer patient
needed chemotherapy, even though some people develop life-threatening
neutropenia.  Of course, some babies might develop severe illness if they
don't get enough of their mothers' milk.

Because there are other choices, in my opinion, one should not give
combination birth control pills to lactating mothers.  I even worry about
using other hormonal methods (Depo, progestin-only pill, Norplant) before 6
weeks postpartum.  Also, mothers become excellent lactaters knowing that they
are depending on LAM for the first 6 weeks.  I have a few that accept LAM
after that 1st 6 weeks, too.