Leviticus - Chapter 12

This chapter sets out the rules for purification after childbirth.  

On the eight day the boy is to be circumcised.  Then the woman must wait 33 days to be purified from her bleeding.  When the time of purification is completed, the woman must bring a one-year-old lamb for a burnt offering and a young pigeon or turtledove for a purification offering. She must bring her offerings to the priest at the entrance of the Tabernacle.  The priest will then present them to the Lord to purify her.   Then she will be ceremonially clean again after her bleeding at childbirth. If a woman cannot afford to bring a lamb, she must bring two turtledoves or two young pigeons. One will be for the burnt offering and the other for the purification offering.

These rules were followed on the birth of Jesus, as recorded in Luke Chapter 2:

"And when eight days were completed for the circumcision of the Child, His name was called Jesus, the name given by the angel before He was conceived in the womb. Now when the days of her purification according to the law of Moses were completed, they brought Him to Jerusalem to present Him to the Lord (as it is written in the law of the Lord, “Every male who opens the womb shall be called holy to the Lord”),  and to offer a sacrifice according to what is said in the law of the Lord, “A pair of turtledoves or two young pigeons.”"