1. The word "horse" is not in the Constitution so you are not allowed to own one and ride one, right?
2. The word "cancer" is not in the Constitution so you are not allowed to have it treated if you get it, right?
3. The word "music" is not in the Constitution so you are not allowed to play it, write it or listen to it, right?
Of course, this is wrong, and there is a good reason why that is - its thanks to one of your Founding Fathers, John Adams
The presence or non-presence of a word in your Constitution is utterly irrelevant. The right to have an abortion might not specifically appear in the Constitution but is it covered by other rights granted therein. The Constitution cannot specify every possible right a person might be granted, which is why John Adams was so insistent on the inclusion in the Bill or Rights of the Ninth Amendment.
Ninth Amendment
"The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people."
In Roe v Wade, SCOTUS ruled that the right to an abortion was implicit (as in
"capable of being understood from something else though unexpressed"). This is held in the meaning of the Ninth Amendment; which addresses both your claim, and my list above - it ensures that
the Bill of Rights is not seen or interpreted as granting only the specific rights it addresses.
The court ruled that the right to an abortion was one of those non-enumerated rights covered by the Ninth Amendment. Although not touched on by SCOTUS, it could also be argued under the due process clause of the Fifth Amendment that the term
"liberty" as used in that clause means
"freedom from arbitrary and unreasonable restraint upon an individual." , so a blanket ban on abortion could be seen as an unreasonable restraint, therefore a violation of the Fifth Amendment
NOTE: I learned all this stuff in Current Affairs and Civics classes in the 6th and 7th form (year 12 &13 - 1972 & 73), in New Zealand, as it was happening in the US. Don't American kids have Civics classes at school - are they not taught about their own Constitution?
.
.