Eileithyia is the goddess of childbirth and labor pains. According to some there were two Eileithyiai, one who furthered birth and one who protracted the labor.
She was born in a cave near Knossos, Crete, and became the main place of worship for the goddess. The goddess was also worshipped in Olympia, which is attested by the discovery of a shrine attributed to her, while other shrines have also been found in Tegea, Argos and Aigion; icons of the goddess were also found in Athens.
Birth of Herakles
When Alkmene went into labor Eileithyia (or arguably The Moirai aka The Fates) at the request of Hera sat outside Alkmene's bedroom with her legs crossed and held together by both hands with intertwined fingers. This was preventing Alkmene from giving birth to either Iphikles or Herakles. This continued for several days and the delivery was killing Alkmene and would have subsequently killed Iphikles & Herakles but Galinthias (who in some lesser accepted versions was aided by The Furies) emerged and falsely announced that Alkmene had given birth. This news shocked Eileithyia and caused her to break her concentration and position allowing Alkmene to actually give birth. Hera (or in some versions Eileithyia) was so furious that Galainthias's lie had allowed the birth of Herakles (she did not care that Iphikles had been born) that she punished Galinthias by transforming her into a weasel. Hekate (goddess of witchcraft) however took pity on Galinthias and made her an attendant. Herakles even built a temple to Galinthias later in life.