I agree with Dr. Newman that the combined pill can reduce milk supply.
 Unfornately, because this is not a universal phenomenon, some MD's think
that BF women can be given the combined pill if they want it as long as they
are warned that it might decrease their milk supply.  And it usually does.

I feel that if a woman wants a pill (usually because that is what she is used
to), the progestin-only pill can be started at 6 weeks postpartum when the
milk supply is well established......V. Nichols-Johnson, MD