CHAPTER 4--OF ADOPTION
Art. 214. Reciprocal rights and duties of adopter and adopted
A. Married persons must concur in the adoption of another person. One of them cannot adopt without the consent of the other.
B. The adopted person is considered for all purposes as the legitimate child and forced heir of the adoptive parent or parents, including the right of the adopted person or his lawful descendants to inherit from the adoptive parent or parents or the relatives of the latter by blood or by adoption, and the right of the adoptive parent or parents or the relatives of the latter by blood or by adoption to inherit from the person adopted or his lawful descendants, in the same manner and to the same extent as if the person adopted were in fact the legitimate child of the adoptive parent or parents. The adopted child is a forced heir to the same extent as other children.
C. If the adoptive parent is married to a blood parent of the adopted person, the relationship of that blood parent and his blood relatives to the adopted person shall remain unaltered and unaffected by the adoption. Otherwise, upon adoption: the blood parent or parents and all other blood relatives of the adopted person, except as provided by Ch.C. Article 1264, are relieved of all of their legal duties and divested of all of their legal rights with regard to the adopted person, including the right of inheritance from the adopted person and his lawful descendants; and the adopted person and his lawful descendants are relieved of all of their legal duties and divested of all of their legal rights with regard to the blood parent or parents and other blood relatives, except the right of inheritance from them.
Amended by Acts 1948, No. 454,§ 1; Acts 1958, No. 514,§ 1; Acts 1978, No. 458,§ 1; Acts 1990, No. 147,§ 1, eff. July 1, 1990; Acts 1995, No. 1180,§ 1, eff. Jan. 1, 1996.
To me, this sounds like: you adopt her and maternal grandparents (and all other relatives on the mother's side) loose all rights to the child.