Towards the end of his career as senator, Loudon introduced an amendment to a health insurance bill that legalized the practice of midwifery in Missouri. (Missouri had previously been one of a minority of states that prohibited anyone other than registered nurses from serving as a midwife.) The Missouri State Medical Association, which represents physicians in the state, sued to block the controversial provision, arguing that it violated the state's single-subject rule for legislation. In 2008, the Missouri Supreme Court voted, 5–2, to uphold the legislation, finding that the Missouri State Medical Association lacked standing to sue.