There are three distinct stages of labor in the dog and cat. Dystocia can occur in any of the three stages:
1. The first stage is characterized by cervical dilatation and rupture of the amniotic fetal sac.
2. The second stage is the actual delivery and or passing of the fetus through the birth canal into the real world.
3. The third stage is the delivery of the afterbirth; known as the placenta. Dogs and cats are multiparous, that is they usually give birth to multiple fetuses. A female may pass one fetus than its afterbirth or pass two fetuses and one afterbirth and so on. There is no logic so owners have to be patient.
About 24 hours prior to the first stage of labor the body temperature in the dog (not cat) will drop to about 97 degrees F. The normal canine temperature is 102.0 F. That always indicates labor will start in about 18-24 hours. The female will appear restless, pace around, lay down in her whelping box and just be totally uncomfortable. Once labor begins, a fetus should arrive anywhere up to an hour or they may be born one after another in short order. Never let contractions go longer than 2-3 hours. If this occurs, placental abruption and separation occur and the fetus may be born stillborn.
Learn more about canine obstetrical care of the dog & cat.