Complex sentence: In the United States, the middle classes were especially receptive to the medicalization of childbirth, which promised a safer and less painful labor, and in fact the ability to labor without pain was part of the early feminist movement.
Split into simpler sentences: In the United States, the middle classes were especially receptive to the medicalization of childbirth, which promised a safer and less painful labor. In fact, the ability to labor without pain was part of the early feminist movement.