Yesterday, May 31, is the date in the West on which is celebrated the Visitation of Mary to her relative Elizabeth; they are both pregnant. Mary is pregnant with Jesus and Elizabeth with John the Baptist. And in this extraordinary embroidered, Bohemian orphrey panel which dates from the 1400s, the babies are depicted in their mothers' wombs with great anatomical accuracy.
My understanding had always been that it was Leonardo Da Vinci who had been the first to depict the unborn foetus sometime between 1510-1511. It may well be that the Visitation above is later than recorded, or that it shows there was another, earlier anatomical study that we do not know about. How wonderful it would be to have further research.