above the uterine glands. These proliferated cells are called "decidual cells." The ovum, lying in the folds of the hypertrophied mucosa, finally is completely surrounded. That portion of the mucous membrane reflected over the ovum is the decidua reflexa. The portion under the ovum, the decidua serotina, and the uterine mucous membrane elsewhere, the decidua vera. The decidua serotina helps to form the placenta; the decidua vera undergoes a partial atrophy in the latter months of pregnancy and is cast off in part with the ovum in labor, in part by disintegration in the lochial discharge; the decidua reflexa begins to undergo degeneration at the second month and by the seventh month has disappeared. DISEASES. 1. Apoplexies.-These are a common cause of early abortions, and are apt to occur prior to the second or third month. Causes.-Bright's disease, repeated congestions from frequent coitus, injuries, blows, etc. 2. Inflammations, Chronic. (a) Hyperplastic endometritis gravidarum. The hypertrophy of the mucous membrane is exaggerated, deflects nourishment to itself and gives rise to apoplexy and early abortion of a fleshy mass. It is usually the result of chronic endometritis prior to pregnancy. The decidual apoplexies may be multiple and distributed all over the surface of the ovum, projecting into its cavity, producing the socalled "subchorial tuberous hæmatomata of the decidua." (b) Polypoid endometritis gravidarum. The hypertrophy confined to certain areas. Is very rare. Leads to abortion, second to fourth month. (c) Catarrhal endometritis gravidarum. There is an abnormal hypertrophy of the uterine glands, giving rise to the secretion of a few ounces to a pint or more, with periodic discharges, of thin mucus, called hydrorrhoea gravidarum. (d) Cystic endometritis gravidarum occurs very early. The glands hypertrophy. May be cured by subsequent growth of the deciduæ or may continue to produce hydrorrhoea gravid arum. 3. Inflammations, Acute.-(a) Hemorrhagic endometritis, as occurs in cholera. Causes abortion. (b) Exanthematous endometritis, the exanthema developing on the uterine mucous membrane, as on other mucous membranes. In several reported cases of measles complicating pregnancy, abortion has occurred about the time of appearance of the eruption. (c) Purulent endometritis. Very rare. 4. Atrophy.-May affect either of the deciduæ. Ill-developed placenta may result, or ovum not properly held in place may drop and develop a cervical pregnancy." 66 5. Tumors. Decidual polyps of fibrin on a basis of decidual tissue, like stalactitic formation on rocks. "Deciduoma," a tumor composed of decidual elements, remaining, perhaps, a long time in utero, occasioning hemorrhage, discharges, and, perhaps, sepsis, but so lightly attached to the uterine wall that its removal is easy. Another variety of deciduoma (deciduo-sarcoma) is malignant, giving rise to metastases and ending fatally six or seven months after confinement. The Placenta. (A) Development.-At the third month the chorion villi atrophy, except at the decidua serotina, where they take on an extraordinary growth to form the placenta. Each villus is composed of connective tissue holding capillary blood vessels, is covered with epithelium, and projecting into the maternal tissue is surrounded by a capillary network from the maternal bloodvessels. Later, these capillary networks disappear, leaving large sinuses or lacunæ, which receive blood from the little curling arteries rising up through the decidua serotina and into which the villi of the placenta dip. (B) The Fully Developed Placenta.-At term the placenta weighs one pound, is one inch thick at its central portion and seven inches in diameter. The foetal side is covered by the amnion and penetrated by the cord. The maternal surface is dark red, divided by sulci into lobules or cotyledons and covered with a grayish transparent membrane composed of the cells of the upper layer of the decidua serotina. It is normally situated at the fundus, anteriorly or posteriorly. (C) Functions.-It absorbs oxygen and nutriment, acting as vicarious lung or gill, and serves as alimentary tract, kidney, liver, and bowel. The epithelium of the villi, in carrying on these functions, has a selective power. Variola germs are readily absorbed, tuberculosis very rarely. ANOMALIES. (a) Position-as placenta prævia. (d) Weight-may be above or below normal. (e) Number-as placenta duplex, tripartita, etc. There may be accessory growths, as placenta succenturiatæ, placenta spuria, marginata, etc. DISEASES.p (a) Edema.-Often accompanies hydramnion and macerated fœtus; stenosis of umbilical vein; general effusions in the mother. The villi may be normal. (b) Degenerations: 1. Cellular Infiltration. --Occurs in syphilis. Villi are distended with granulation cells, blood vessels obliterated, and foetal life perishes. 2. Fibrous and Fatty Degeneration of Villi.-Causes. Any abnormality, accident or disease of placenta abrogating its function, as hemorrhage from the placenta, chronic interstitial placentitis, diseases of endometrium. "White infarcts" and fibrin nodes of the placenta, formerly believed to be pure fibrin formations, are probably localized degenerations of the decidua. Prognosis. If extensive, foetus dies. If small, a corresponding degree of ill development of foetus. Primary fatty change only occurs after death of the foetus. 3. Phthisical Placenta. - An exudate from villi into lacunæ, which undergoes a cheesy change. 4. Calcareous.-Very common. Occurs in indifferent places, and has no effect on functions of the placenta. |