Threescore and six days — The time in both particulars is double to the former, not so much from natural causes, as to put an honour upon the sacrament of circumcision, which being administered to the males, did put an end to that pollution sooner than otherwise had been.
Related Commentaries of Leviticus 12:5
Leviticus 12:5
5 But if she bear a maid child, then she shall be unclean two weeks, as in her separation: and she shall continue in the blood of her purifying threescore and six days.