In 1902 the Midwives Act for England and Wales established certified midwifery as an official part of the medical profession. Women were initially allowed to work as midwives if they had either completed training or proven to the board that they had practiced for a minimum of one year prior to the passing of the Act and were of “good character.” Changes to the Act, culminating in the 1936 Midwives Act, saw such provisions for existing midwives removed, and only women who had completed the training and examination as set out by the Central Midwives Board were permitted to work as midwives in England and Wales. The changes to the Act brought in restrictions as to who could work as a midwife, but also granted greater medical autonomy to midwives. Such medical autonomy was recognised through increased freedom to administer medications—although the administering of drugs was still highly regulated—and the potential for training in gas and air analgesia. The changes to the Midwives Act and the training of midwives changed midwifery and gave more parturient women access to medicalized care. This paper addresses how professional hierarchies influenced the practice of midwifery in England and Wales and argues that, throughout the first half of the twentieth century, the influence of these professional hierarchies lessened as midwifery became a relatively autonomous branch of the medical profession. This paper focuses especially on advancements in obstetrical science and technology to consider how midwives both used and influenced these advancements. Looking at the regulation of midwives and the associated disciplinary hearings reveals a change in emphasis throughout the first half of the twentieth century: by the latter half of this period such hearings were predominantly about the midwife’s medical technique rather than her character or hygiene. Studying the correlation between medical advancements and the associated professional hierarchies shows that, while the regulation of midwifery became more rigorous throughout the twentieth century, midwifery also became an integral branch of the medical profession.