That is the major flaw in Roe v. Wade. They just made up the trimester thing on the fly. The truth is that there have been great advances since Roe was decided, and the day will come when a fertilized egg can be removed safely from a woman's womb, placed into an artificial womb and then go to full term. Does this mean Roe will be its own demise? Quite possibly.
Justice O'Connor raised this point in the 80s. The state's interest in the health of the mother and prenatal child will always be weighed against the mother's privacy right under the XIV Amendment, the reasoning of Roe is on shifting sands, subject to advances in science that push back the date of fetal viability. When we reach that point, the matter will be decided on Roe's judicial progeny.
