S.D. Codified Laws § 58-18-32
Any group health insurance policy and group service or indemnity type contract issued by a nonprofit corporation which offers coverage for a family member of an insured or subscriber shall provide that the health insurance benefits applicable for children are payable with respect to a newly born child of the insured or subscriber from the moment of birth or to a newly adopted child of the insured or subscriber from the beginning of the six-month adoption bonding period. The newly born or newly adopted child shall be added to the policy without underwriting and without the imposition of any preexisting waiting period. Any policy or contract issued before July 1, 1984, shall, upon its next anniversary date, also provide that the health insurance benefits applicable for children shall be payable with respect to a newly born child of the insured or subscriber from the moment of birth or to a newly adopted child of the insured or subscriber from the beginning of the six-month adoption bonding period.
SDCL 58-18-32