Subpart B of 45 Code of Federal Regulations Part 46 (CFR) identifies the criteria according to which research involving pregnant women, human fetuses, and neonates can be conducted ethically in the United States. As such, pregnant women and fetuses fall into a category requiring “additional protections,” often referred to as “vulnerable populations.” The CFR does not define vulnerability, but merely gives examples of vulnerable groups by pointing to different categories of potential research subjects needing additional protections. In this paper, I assess critically the role of this categorization of pregnant women involved in research as “vulnerable,” both as separate entities and in combination with the fetuses they carry. In particular, I do three things: (1) demonstrate that pregnant women qua pregnancy are either not “vulnerable” according to any meaningful definition of that term or that such vulnerability is irrelevant to her status as a research participant; (2) argue that while a fetus may be vulnerable in terms of dependency, this categorization does not equate to the vulnerability of the pregnant woman; and (3) suggest that any vulnerability that appends to women is precisely the result of federal regulations and dubious public perceptions about pregnant women. I conclude by demonstrating how this erroneous characterization of pregnant women as “vulnerable” and its associated protections have not only impeded vital research for pregnant women and their fetuses, but have also negatively affected the inclusion of all women in clinical research.