Ovulation is the release of eggs that are ready to be fertilized. A common misconception is that a dog's ovulation happens about 11 days after she comes into heat. Every dog is different, the onset of ovulation can vary vastly from dog to dog. Your vet can confirm where your pup is in her cycle.
The four stages of a dog's heat are proestrus, estrus, diestrus and anestrus. Proestrus, which lasts between one and 17 days, is when the dog's ovaries prepare for ovulation and the uterus prepares for pregnancy. At the end of this stage, your pup's estrogen levels are at their peak. Estrus, which lasts from three to 21 days, is the time for mating. Estrogen decreases and progesterone increases; a release of luteinizing hormone -- or LH -- stimulates ovulation about two days later. Usually, this happens on the third day of estrus but can be different for any dog. Diestrus follows estrus and lasts about two months. If your pup has successfully mated, she's pregnant; if not, she may experience symptoms mimicking pregnancy, known as a false pregnancy. Anestrus is the final stage, lasting 50 to 80 days, and is a period of reproductive rest.
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