No, cats do not stay in heat after they get pregnant. The more technical word for “heat” is oestrus (estrus in America) which is the period of sexual receptivity. During oestrus the queen (unspayed female cat) seeks out males and allows mating. Mating is necessary for ovulation to occur in the female cat.
This is quite technical and difficult in terms of timing. When mating occurs stimulation of the female’s vagina causes the female’s anterior pituitary gland to release luteinising hormone. It’s normal for several matings to occur before luteinising hormone is released. Once this hormone surge has taken place ovulation occurs 24 to 30 hours after the release of luteinising hormone. Between three and seven ova (eggs) are released in each cycle depending upon environmental conditions and the cat’s age and physiological condition. Fertilisation takes place in the upper region of the oviducts. The newly formed embryos move slowly from the oviducts to the uterus over a period of 5 to 6 days.
Diestrus begins at the ending of sexual receptivity after ovulation and lasts until the corpus lutea regress. Corpus luteum is a mass of cells that forms in an ovary and is responsible for the production of the hormone progesterone during early pregnancy.
To recap, sexual receptivity i.e. the period described as “heat” ends after ovulation. Ovulation describes the release of eggs from the ovary and fertilisation can take place immediately after ovulation. Hope this helps. I am indebted to Linda P Case’s book The Cat, It’s Behavior, Nutrition & Health (at page 58).
Pregnancy: the term used to describe the period in which a fetus develops inside the womb or uterus. I have decided that for cats pregnancy starts on conception (fertilisation). For women it apparently begins from the first day of the woman’s last normal menstrual period (LMP), even though the development of the fetus does not begin until conception (americanpregnancy.org).
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