The Teaching to the Venerable Nanda on Entry into the Womb
In The Teaching to Venerable Nanda on Entry into the Womb, the Buddha gives a detailed account to his half-brother Nanda of the thirty-eight weeks of human gestation. The sūtra explains conception in terms of how the antarābhava (the being in the state between death in one life and birth in the next) enters the womb, and details the physical composition of the embryo, the suffering of the newborn being, and the miseries experienced over the course of a lifetime. Including as it does the most comprehensive ancient Indian account of gestation, it was an important source for embryology in Tibetan medicine.