I may not be qualified to answer this question, but I would like to
share my experience. There are many issues involved in the use of
fertiltiy drugs during breastfeeding.  The first issue is what effect
lactation is having on a woman's fertility and fecundity, lactation
itself may be contributing to infertility.  The second big unknown is
the effects of the drugs if any on the nursing child.  The third over-
riding issue I have seen is the desire of the mother to not lose the
breastfeeding relationship in hopes of conceiving another baby that
may never become a reality. The fear of loss is very great in
infertile women,  especially those who had a long period of primary
infertility. The issue of the biological clock is another
consideration, many mothers with infertility problems are older and
really feel the clock ticking. As a child grows and is nursing less
and less, the potential exposure to the drugs in reduced. For
instance a 3 year old who nurses twice a day will not receive as much
exposure as a six month old exclusively breastfed baby.  Many
fertility drugs inhibit lactation, clomid and parlodel have been
known to dry up milk fast. Taking all of these things into
consideration, it has been my experience that some MDs are willing to
treat a lactating mother of an older baby (child).  I know of several
women who conceived on clomid while nursing. In spite of the unknown,
but potentially harmful risks, they have used the drugs. I have a
beautiful daughter who is an example of this.  Cathy