Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 3
वृद्धं तं पञ्चतां प्राप्तं महिष्यनुमरिष्यती ।और्वेण जानतात्मानं प्रजावन्तं निवारिता ॥ ३ ॥
vṛddhaṁ taṁ pañcatāṁ prāptaṁmahiṣy anumariṣyatīaurveṇa jānatātmānaṁprajāvantaṁ nivāritā
Bāhuka died when he was old, and one of his wives wanted to die with him, following the satī rite. At that time, however, Aurva Muni, knowing her to be pregnant, forbade her to die.