Mahapadanasutta 1.23.1

1.23.1

Dhammatā esā, bhikkhave, yathā aññā itthikā nava vā dasa vā māse gabbhaṃ kucchinā pariharitvā vijāyanti, na hevaṃ bodhisattaṃ bodhisattamātā vijāyati. Daseva māsāni bodhisattaṃ bodhisattamātā kucchinā pariharitvā vijāyati.

It’s normal that, while other women carry the infant in the womb for nine or ten months before giving birth, not so the mother of the being intent on awakening. She gives birth after exactly ten months.