14th under privacy which includes the government not invading your privacy of what you do with your own body. Back when the Constitution was being written. Nothing like today was possible, it was medically very ancient.
Medically ancient? LOL!
Maybe they left out a "medical amendment" because they knew that the FEDERAL government had no reason, or jurisdiction, to intervene in medical questions.
That by default makes abortion and all other medical (it's my body) questions up to the states -- as it should be.
It's almost impossible to pass any one-size-fits-all laws at the federal level of ANY issues. Most are best left to the state and local governments, since they are closer to the people affected by the laws.
Federal laws are intended to protect the states. Unfortunately, the politicians were able to start down that slippery slope when they started making Constitutional amendments like Prohibition. The fact that it was repealed proves the federal government is not the appropriate level for making universal laws unless the issue is DIRECTLY called out in the Constitution.
Abortion is according to you a medical issue. Ask yourself why there is not a federal law protecting all specific medical procedures. Haven't seen anyone marching for Constitutional protections for, say, fertility treatments, or transgender hormone therapy, or even organ donations and transplants.
Maybe it's because abortion is not about protecting a woman's rights, but more about blocking state's rights to debate, vote on and pass their own laws on the issues?