Glossary of Terms

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The expulsion from the uterus of a living fetus before it reaches a viable age, or more commonly the expulsion of a dead fetus of recognizable size at any stage of the gestation period.


The failure of the secretion of milk (lactation) from any cause other than the normal ending of the lactation period.

Bicornuate uterus

bi-kor´nu-āte u´ter-us
Two separate uterine “horns” that have separate cervices opening into one vagina.


The opening between the uterus and the vagina.

Cesarean section (C-section)

The process of delivering offspring by surgical incision through the abdomen (laparotomy) and uterus (hysterotomy) to deliver one or more offspring.


Female parent, mother.


Difficult delivery.


An organism in its early stages of development, especially before it has reached a distinctively recognizable form.


The periodic state of sexual excitement that immediately precedes ovulation and during which the female is most receptive to mating. In rats it occurs every 4-5 days and is not seasonal.


The term denoting irregular, reduction and cessation of estrus cycles due to disruption of hormones in the aged female rat. Can occur starting at 9-12 months of age, but more typically seen between 15-18 months of age.


The unborn young having a basic structural resemblance to the adult animal.


See Estrus.


The process by which birth occurs, beginning with contractions of the uterus and ending with the expulsion of the fetuses and the placentas.


The secretion of milk by the mammary gland that provides nourishment to the pups.


A ventral arching of the spine by the female during estrus.

Maceration (fetal)

The degenerative changes with discoloration and softening of tissues, and eventual disintegration, of a fetus retained in the uterus after its death.


The act of pairing a male and female for reproductive purposes.


An infection of the uterus after delivery.


A nutritious fluid produced by the dam’s mammary glands for feeding their offspring.

Mummification (fetal)

The conversion of a retained dead fetus to a dehydrated state.



Oxytocin (natural)

A hormone produced by the pituitary gland that stimulates the contraction of uterine muscles during labor and facilitates lactation.

Oxytocin (injectable Pitocin)

A hormone given IM to stimulate labor.


The act or process of giving birth.


A temporary vascular organ joining the dam and fetus that transfers oxygen and nutrients from the mother to the fetus, and permits the release of carbon dioxide and waste products from the fetus.


Existing or occurring after birth.


Existing or occurring before birth.


Relating to a first pregnancy or birth.


Offspring (immediate descendants).


The term for rat offspring.


A uterine infection where the uterus fills with pus.

Resorption (embryonic/fetal)

The organic process in which the embryo/fetus undergoes lysis and assimilation.


A profound hemodynamic and metabolic disturbance due to failure of the circulatory system to maintain adequate perfusion of vital organs.


Male parent, father.


A fetus which has died in the uterus, during labor, or during delivery that exits the body.

Torsion (uterine)

The act or process of the uterine horn(s) being twisted or rotated.

Umbilical cord

A flexible cord, containing the umbilical arteries and vein, which connects the developing embryo or fetus with the placenta.


To accustom the young of a mammal to take nourishment other than by suckling.


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