Breech birth

A  is when a baby is born bottom first instead of head first, as is normal. Around 3–5% of pregnant women at term (37–40 weeks pregnant) have a breech baby. Due to their higher than average rate of possible complications for the baby, breech births are generally considered higher risk. Breech births also occur in many other mammals such as dogs and horses, see veterinary obstetrics.

Quotes

 * Those at whose birth the feet appeared first, instead of the head, which is considered the most difficult and dangerous form of parturition, are called Agrippae, a word formed from aegritudo, or "difficulty," and pedes (feet). But Varro says that the position of children in the womb is with the head lowest and the feet raised up, not according to the nature of a man, but of a tree. For he likens the branches of a tree to the feet and legs, and the stock and trunk to the head. "Accordingly," says he, "when they chanced to be turned upon their feet in an unnatural position, since their arms are usually extended they are wont to be held back, and then women give birth with greater difficulty. For the purpose of averting this danger altars were set up at Rome to the two Carmentes, of whom one was called Postverta, the other Prorsa, named from natural and unnatural births, and their power over them."
 * Aulus Gellius, Attic Nights, XVI, xvi. That the name Agrippa was given to those whose birth was difficult and unnatural; and of the goddesses called Prorsa and Postverta.
 * John C. Rolfe, ed. The Attic Nights of Aulus Gellius, vol. 3 (1928), p. 185
 * Varro] Ant. Rer. Div. xiv, frag. 17b, Agahd.
 * Carmentes] Carmenta was a birth-goddess, whose festival, the Carmentalia (or Karmentalia) occurred on 11 and 15 January. The Carmentes may originally have been wise women who assisted at births and were later deified (Fowler, Roman Festivals, pp 290 ff.).
 * Postverta] That is, head foremost.
 * Prorsa] That is, feet foremost.