To many, the insertion of the mitzvah of mila, circumcision, in the presentation of the laws of the yodedet, the woman who gave birth, may just seem to be a narrative coincidence. Once the Torah was taking about the birth of a boy, it also mentioned mila. The commentators, however, find it bewildering. What does one have to do with the other?
Rabbi Hecht addresses this issue in an Insight from 5756 available at http://www.nishma.org/articles/insight/spark5756-14.html