progesterone assay

progesterone assay,

a blood test that is useful in documenting whether ovulation has occurred and, if so, when. This information may be used to help women with difficulty becoming pregnant. Repeated assays may also be used to monitor the status of the placenta in high-risk pregnancy and progesterone supplementation in patients with an inadequate luteal phase.

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progesterone

a steroid sex hormone that is the principal progestational hormone. Used therapeutically in the treatment of threatened abortion in some species, in estrus control in dogs and cats, and occasionally in treatment of some types of skin diseases.

During the maturation of the ovum, estrogen, the principal female sex hormone, is produced at a high rate. At ovulation estrogen production is sharply reduced and the follicle is replaced by the corpus luteum of which the main function is to produce progesterone. Unless fertilization takes place, the corpus luteum disappears when it has performed its function.

The progesterone produced by the corpus luteum is promptly carried by the blood to the uterus, as was the estrogen that preceded it. Both hormones now work to prepare the uterus for possible conception.

In pregnancy, progesterone acts in a way that protects the embryo and fosters growth of the placenta. By decreasing the frequency of uterine contractions it helps to prevent expulsion of the implanted ovum. It also promotes secretory changes in the mucosa of the uterine tubes, thereby helping to provide nutrition for the fertilized ovum as it travels through the tube on its way to the uterus.

Another function of progesterone is promotion of the development of the mammary glands in preparation for lactation. Prolactin, from the anterior lobe of the pituitary gland, stimulates production of the milk, and progesterone prepares the glands for secretion.

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progesterone assay

the estimation of progesterone in milk is used as a pregnancy test.

progesterone-induced lactation

see lactation induction.

progesterone milk test

assay of progesterone in milk used as a pregnancy test.

progesterone plasma test

the original pregnancy test which survives as the milk progesterone test; used in dogs as a guide in predicting the time of ovulation.

progesterone releasing intravaginal device

used as a means of synchronizing estrus in cows and sheep as an aid to structured artificial insemination programs. Called also PRID.