KARACHI, Pakistan — Nusrat Mochi, now 25, left her parents’ home one day to go to work and never returned. Instead of starting a job as a domestic worker, she ran away to begin a new life, against her family’s wishes, with a husband of her choosing rather than the one they had chosen for her. Her parents’ wrath has trailed her ever since.

In the four years since she and her husband, Abbas Bhatti, now 27, eloped, they have moved twice to escape threats to their lives, they say. Even today, with two small children, they try to keep the location of their home a secret. If threats were not enough, Ms. Mochi’s parents also brought a legal case charging that Mr. Bhatti had kidnapped her.

“I don’t care about my father and mother,” Ms. Mochi said, sitting in her two-room house and cradling her youngest child in her lap. “When they are sending some person to kill me, how can I?”

Their story illustrates the conflicts some women encounter in Pakistan when choosing what are known here as freewill marriages. It also shows how women are increasingly asserting their rights against the traditions of forced marriage and parental authority, implicitly challenging one of the most powerful institutions in Pakistani society.