Yes, that seems to be it.
Yet another liturgical carry-over stemming from Jewish origins. I had never seen or heard of it in the Latin Rite.
The rite of thanksgiving after childbirth still appears in the 1979 edition of the
Book of Common Prayer. Since the first Prayer Book was drawn from the Latin rites used in England in the 16th Century its origin is quite ancient, and certainly has as its supreme example the festival of the Presentation of our Lord and the Purification of Mary celebrated on February 2.