Divorcing a pregnant woman is valid and effective. Her `Iddah (woman's prescribed waiting period after divorce or widowhood) ends when she delivers.
If a husband steals his wife's jewelry, she has the right to claim it back, if it is hers or she has borrowed it. However, if the jewelry is the husband's possession or he has borrowed it for his wife, she has no right to demand it. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.