<Ul> <Li> Accumulation of fluids other than blood or of unknown constitution . One study came to the conclusion that postmenopausal women with endometrial fluid collection on gynecologic ultrasonography should undergo endometrial biopsy if the endometrial lining is thicker than 3 mm or the endometrial fluid is echogenic . In cases of a lining 3 mm or less and clear endometrial fluid, endometrial biopsy was not regarded to be necessary, but endocervical curettage to rule out endocervical cancer was recommended . </Li> <Li> Myometritis--inflammation of the muscular uterine wall . </Li> </Ul> <Li> Accumulation of fluids other than blood or of unknown constitution . One study came to the conclusion that postmenopausal women with endometrial fluid collection on gynecologic ultrasonography should undergo endometrial biopsy if the endometrial lining is thicker than 3 mm or the endometrial fluid is echogenic . In cases of a lining 3 mm or less and clear endometrial fluid, endometrial biopsy was not regarded to be necessary, but endocervical curettage to rule out endocervical cancer was recommended . </Li> <Li> Myometritis--inflammation of the muscular uterine wall . </Li> <P> Most animals that lay eggs, such as birds and reptiles, including most ovoviviparous species, have an oviduct instead of a uterus . However, recent research into the biology of the viviparous (not merely ovoviviparous) skink Trachylepis ivensi has revealed development of a very close analogue to eutherian mammalian placental development . </P>

When does the uterus become a pelvic organ in pregnancy