This regulation also governs Institutional Review Board (IRB) membership, functions, and operations. In addition, it includes the general requirements for informed consent and codifies additional protections for vulnerable participants. Subpart A of this regulation is also known as the Common Rule. Subparts B, C, and D include additional protections to vulnerable populations, such as pregnant women, prisoners, and children. It is enforced by the DHHS Office for Human Research Protections.