Missouri is stepping up... I believe the law below is the one being used for when the mother uses drugs to the extent it hams the child.
Missouri Revised StatutesChapter 1
Laws in Force and Construction of Statutes
Section 1.205
August 28, 2013
Life begins at conception--unborn child, defined--failure to provide prenatal care, no cause of action for.
1.205. 1. The general assembly of this state finds that:
(1) The life of each human being begins at conception;
(2) Unborn children have protectable interests in life, health, and well-being;
(3) The natural parents of unborn children have protectable interests in the life, health, and well-being of their unborn child.
2. Effective January 1, 1988, the laws of this state shall be interpreted and construed to acknowledge on behalf of the unborn child at every stage of development, all the rights, privileges, and immunities available to other persons, citizens, and residents of this state, subject only to the Constitution of the United States, and decisional interpretations thereof by the United States Supreme Court and specific provisions to the contrary in the statutes and constitution of this state.
3. As used in this section, the term "unborn children" or "unborn child" shall include all unborn child or children or the offspring of human beings from the moment of conception until birth at every stage of biological development.
4. Nothing in this section shall be interpreted as creating a cause of action against a woman for indirectly harming her unborn child by failing to properly care for herself or by failing to follow any particular program of prenatal care.
http://www.moga.mo.gov/statutesearch/StatHtml/0010000205.htm
As we can see legal protections are already there this is an enforcement of those protections.