Sara,
        Alesse is a "new" OCP released in the US approximately 6/97. It contains
0.1mg levonorgestrel and 20 micrograms ethinyl estradiol.  It is not the
only OCP available in the US with this low estrogen dosage - Lo-Estrin 1/20
has been available for awhile.  These pills still contain estrogen - most
other commonly used OCP's have 30 or 35 micrograms of estrogen.  I imagine
there is no data on lactation performance comparing these 2 different
estrogen doses... I still tend to recommend the " minipill" which has no
estrogen to my breastfeeding mothers who desire to use an OCP.  The
advantage to the estrogen containing pills is regular menstraul periods but
I often find that the potential irregular bleeding with the minipill (I use
Micronor) is not a large problem for breastfeeding mothers as long as it is
something they are aware may happen (though it often doesn't).

Lisa,
        Tom Hale's book regarding Levothyroxine states that most studies indicate
there is minimal transfer into milk but that reports " conflict" It
suggests that checkiing the infants thyroid function  may be indicated.  He
reports adverse effects to include: " nervousness, tremor, agitation and
weight loss".  Hope this info helps.
                                Pamela Berens M.D. OB/GYN