20 weeks is 4 1/2 months. Abortion after 6 months generally is banned, with the wide maternal health exception.
A baby at 20 weeks looks like a baby at 26 weeks, except smaller and scrawnier - the mother’s uterus reaches the height of her navel, and the baby would fit curled on her palm.
You might not have meant to be misleading, but your phrase "...generally banned" IS misleading.
Using your "health" exception, babies up to 40 weeks gestation (full term) are destroyed by abortionists who, on camera, have laughingly described how they will interpret (i.e. fabricate) that "health" exception in any way they please.
This happens all over America, every day, in "clinics" aka abortuaries like Gosnell's -- which are de facto legal because state gov'ts willingly look the other way.
And while the abortion industry claims that "only" about 500 post-20 week abortions are performed, nationwide, per year, that claim was long ago been exposed as a lie.
in 1997, reporter and journalism professor Ruth Padawer found that one single abortion clinic in Englewood, New Jersey --alone-- blithely admitted to performing over 1500 post-20 week abortions per year.