I'm not familiar with 'Micro' Retin-A, but Dr. Hale's book does have information about Retin-A used topically for acne or wrinkling. Retin-A is the trade name (also Renova, Vesanoid, Vitamin A Acid, etc.) and Tretinoin is the generic name.
When used topically, Retin-A is unlikely to cause any problems in nursing mothers, because so little of it is absorbed and the concentration in the blood is essentially zero. However, it is sometimes given orally to treat leukemia or psoriasis, and in this case, Dr. Hale states that "transfer into milk is likely and it should be used with great caution by a breastfeeding mother."
Not all herbal preparations are safe to take while breastfeeding. While herbs are "natural", they can be quite potent and cause serious side effects. Dr. Hale's book does contain some information about herbs and lactation. For more information about herbs and breastfeeding, check out
http://lalecheleague.org/llleaderweb...nJul98p43.html or contact Mechell Turner, IBCLC and herbalist at birthandbreastfeeding.com or directly via e-mail at mrturner@vnet.net.
I hope this information helps,
Anne