A former Hilton Head Hospital executive pleaded guilty to federal charges Thursday stemming from an alleged scheme to pay kickbacks and increase Medicaid reimbursements. Gary W. Lang, the hospital's vice president of business development from 2004 to 2006, pleaded guilty to conspiracy to violate an anti-kickback law and will enter into a plea agreement with the U.S. Attorney's Office, court documents said. The accusations stem from a "whistleblower" civil lawsuit that contends the prenatal clinic, Clinica de la Mama, was paid to refer clients to Hilton Head Hospital and four Georgia hospitals for Medicaid-paid deliveries.