What is the most likely cause of profuse vaginal bleeding in a 32-year-old pregnant woman who denies abdominal pain?

The most likely cause of profuse vaginal bleeding in a pregnant woman who denies abdominal pain is placenta previa. This condition occurs when the placenta is implanted in such a way that it partially or completely covers the cervix. As the pregnancy progresses and the cervix begins to thin and dilate in preparation for labor, the placenta can be disrupted, leading to significant vaginal bleeding.

Since the woman is not experiencing abdominal pain, this further supports placenta previa as the likely cause, as other conditions associated with bleeding, such as ectopic pregnancy or uterine rupture, typically present with severe abdominal pain. While gestational hypertension can lead to complications such as placental abruption, which does cause pain, the absence of abdominal pain makes placenta previa a more fitting diagnosis in this case.