Letters.

Breast-Feeding and DMPA

I applaud Dr. Anita L. Nelson for prioritizing breast-feeding enough to study the effects of medications on milk supply ("Postpartum DMPA Doesn't Prevent Lactation" Jan. 1, 2002, p. 7). It is interesting that the duration of lactation was not different in the study groups, but does this prove that the contraceptive is not interfering with lactation or that it has no effect on milk supply?

Most mothers in the study reported that they didn't have enough milk, but it is not clear whether this was real or perceived. If it is real, and if injection of depot medroxyprogesterone acetate (DMPA) is not the cause of a low milk supply what is?

It also is true that many hospital practices interfere with milk supply and that many mothers misread or misunderstand normal infant feeding cues. Many don't know that there are growths spurts in the first few weeks of life that are characterized by increased feeding frequencies. Simply because there were equal numbers of mothers reporting that there was a problem with milk supply, one cannot assume that the group given the DMPA did not have an actual lack of milk unless milk output was measured, which is unclear in the report.

The main objection to use of DMPA before 5 days postpartum is that it will intherefere with lactogenesis II (the "milk coming in"), and it would be useful to have an assessment of a delay in this event.

Finally, given all the hospital practices that can interfere with milk supply and the apparent lack of measurement of milk output, has this study really proved that DMPA doesn't lower milk supply? Or do all theother confounding factors simply have a greater combined effect than that of DMPA?

Christine Betzold