When your pregnant female cat starts dripping milk out of her nipples, her kittens should arrive within 48 hours. That's one of the initial signs that she is going into labor. Once you notice milk production, keep an eye on her for further signs of labor, but don't hover over her and make her uncomfortable. She needs peace and quiet for the birthing process.
A cat's gestation period is approximately two months long, between 60 and 70 days. But if you didn't deliberately breed your cat, you might not know when she got pregnant or how far along in her pregnancy she is. Even your vet can only give you an estimate. About a week before she gives birth, a cat's nipples become larger and pinker. Actual milk leakage tells you the birth is just a day or two away.
Other Signs of Labor
Besides the milk discharge, your mother-to-be cat might become restless, constantly getting up and down. She's not very active, however, just distracted. She might start licking her genitals or meowing a lot. She'll look for a nesting place to have her babies, so prepare a box lined with clean towels or newspapers. She might not use it, but close the door to any areas or closets you definitely don't want the cat giving birth in. If you have other pets in the house, keep them away from her.
Once she's in her nesting box or chosen birthing area, keep an eye on her but leave her alone. She'll start having contractions. You'll see her straining to push out her newborns. Each kitten arrives in an amniotic sac, which usually breaks as he enters the world or is licked away by his mother licks. The placenta follows soon after. Subsequent kittens will arrive in 10- to 60-minutes intervals. If your cat experiences contractions with no sign of a kitten within one hour, call the vet.
A cat going into labor before her milk comes in is a sign that the birth might be premature. Stress can bring on early labor, so avoid doing anything that might distress your cat while she's heavily pregnant. Scenarios that would put her babies in jeopardy include moving to another location, putting her in a boarding situation, bringing new pets into the household, or anything that significantly upsets her routine. Infections, death of a fetus and other issues can also cause premature labor. Take your cat to the vet, as premature labor is likely due to sickness or dead kittens.