The original Hippocratic Oath literally has a line that says “I will not perform an abortion on a woman”. It also says “I will not use the knife”, aka perform surgery. Assisted suicide is also banned.
Again, it’s the product of an ancient time. Back then physicians and surgeons were completely different professions, often rivals. Women had fewer rights.
Furthermore, the Hippocratic Oath takes a very paternalistic view of medicine (ie doctors should do what they think patients need, disregarding what patients want). Modern oaths are more likely to take into account patient autonomy and consent. That’s why modern doctors generally prefer more modern vows. Or no vow at all.