Are women allowed to wear jewelery during pregame warmup in NCAA women's basketball?

RULE 3 Players, Substitutes and Player Equipment
Section 7. Players’ Equipment
Art. 7. Head decorations, head wear and jewelry are illegal. Headbands no wider than 2 inches made of non-abrasive, unadorned (except for the manufacturer’s logo, which shall meet the size restrictions of Rule 3-6), single-color cloth, elastic, fiber, soft leather, pliable plastic or rubber shall be legal.
A.R. 19. Substitute A6 attempts to enter the playing court wearing jewelry, an illegal headpiece or hat. RULING: Substitute A6 shall not be permitted to enter before
removing the jewelry, illegal headpiece or hat. A6 cannot “buy” his or her way into the game and the right to wear the illegal jewelry, illegal headpiece or hat by being
charged with an indirect technical foul.
A.R. 20. Player A5 is found to be wearing jewelry. RULING: At the first dead ball, A5 shall be required to remove the jewelry immediately or be required to leave the game and not return until after removing the jewelry. A5 cannot “buy” the right to wear the jewelry by being charged with an indirect technical foul.

While pregame is not mentioned specifically in the NCAA book, I'd have to say no based on what is there.

Yes.