In Mexico is it believed that exposure of a pregnant woman to an eclipse will cause her infant to have a cleft lip or palate. The belief originated with the Aztecs, who thought that an eclipse occurred because a bite had been taken out of the moon. If the pregnant woman viewed the eclipse, her infant would have a bite taken out of its mouth. An obsidian knife was placed on the woman’s abdomen before going out at night to protect her. This belief remains intact hundreds of years later, the only difference being that today a metal key or safety pin is used for protection”

The Han people have a custom that a pregnant woman is not allowed to eat rabbit meat for fear that the child will be born with a harelip.

A superstition observed among Mexican-Americans involving pregnancy - a pregnant woman who goes out during a full moon or lunar eclipse will give birth to a baby with a harelip or with the features of a wolf. To prevent this, the women would carry a bunch of keys around her waist so that they hang over the baby in order to deflect the moonlight.

From Claude Levi-Strauss' book 'Myth and Meaning: Cracking the Code of Culture:

... a puzzling observation recorded by a Spanish missionary in Peru, Father P.J. de Arrigia, at the end of the sixteenth century, and published in his 'Extirpacion de la Idolatria del Peru' (Lima 1621). He noted that in a certain part of Peru of his time, in times of bitter cold the priest called all the inhabitants who were known to have been born feet first, or who had a harelip, or who were twins. They were accused of being responsible for the cold because, it was said, they had eaten salt and peppers, and were ordered to repent and to confess their sins.

The fable which follows is entitled "From an original manuscript in English, by Mr. John Priestly, in Sir G. Grey's library."

"The moon, on one occasion, sent the hare to the earth to inform men that as she (the moon) died away and rose again, so mankind should die and rise again. Instead, however, of delivering this message as given, the hare, either out of forgetfulness or malice, told mankind that as the moon rose and died away, so man should die and rise no more. The hare, having returned to the moon, was questioned as to the message delivered, and the moon, having heard the true state of the case, became so enraged with him that she took up a hatchet to split his head; falling short, however, of that, the hatchet fell upon the upper lip of the hare, and cut it severely. Hence it is that we see the 'hare-lip.' The hare, being duly incensed at having received such treatment, raised his claws, and scratched the moon's face; and the dark parts which we now see on the surface of the moon are the scars which she received on that occasion."