Stage One: The first stage of labor may pass largely unnoticed. During this stage, the cervix dilates and the uterus starts contracting. It can last for a few hours or for as long as 24 hours. Queens may be restless, overgrooming, pacing, panting, or even vomiting during this stage. They may not eat for up to 24 hours before active labor, although some queens eat normally right up to stage two. No visible contractions are seen, although there may be a clear mucous discharge from the vagina. As the end of stage one labor approaches, most queens will settle in the birthing box, purring loudly and scratching around to prepare their "nest." It is important to ensure that the location where the queen will give birth is warm enough for the neonatal kittens.
Stages Two and Three: During these stages of labor the kittens are delivered (stage two) and the placentas are delivered (stage three). The delivery of the litter is actually a series of stage two and stage three labors. Strong uterine contractions help deliver each kitten from its uterine horn into the uterine body and through the cervix and vagina. Once strong labor starts the entire litter may be born in under two hours, or it may take as long as 24 hours. Most commonly, kittens are delivered every 30 to 60 minutes, although they may be delivered more rapidly. Both head first (2/3 of births) and hindquarters first (1/3 of births) presentations are normal in the cat. A true breech birth is when the tail and rump are presented before the hind legs, and this is a more difficult delivery. The time from the start of active labor to the birth of the first kitten is usually less than 60 minutes. A queen who is in active, hard labor for two hours without delivering a kitten must be assumed to need veterinary attention.