Hyperplasia of the uterine parenchyma, affecting either the whole organ or a large part, and characterized either by enlargement of the entire organ, or only by thickening and elongation of the cervix, may hinder the incubation of the ovum. It may be due to endometritic catarrhal processes; to venous hyperaemia, especially in cases of valvular heart disease; to subinvolution; and sometimes to excessive sexual stimulation, as in prostitutes. Both the change in the shape of the cervix, and the changes undergone by the uterine mucous membrane in cases of extensive uterine hyperplasia (it commonly becomes atrophic and discharges a watery secretion), interfere with the reproductive capacity.
In all cases of chronic metritis, the hyperaemia and hyperplasia of the uterus may give rise to haemorrhages; these sweep away the ovum, and thus lead to impotentia gestandi. And the nutritive changes in the mucous membrane that occur in chronic metritis also interfere with the implantation and incubation of the ovum. Moreover, it is well known that in these cases, even if conception is effected, abortion is extremely apt to occur, owing to the pathological state of the endometrium, which interferes with the normal development of the decidua. Haemorrhages occur in the decidua, and are followed by abortion. And further, the replacement of portions of the muscular tissue of the uterine wall by fibrous tissue, a change which is apt to occur in long continued metritis, interferes with the proper expansion of the uterus during pregnancy, and thus leads to abortion.
On the other hand, it cannot be denied that frequently enough patients with well marked chronic metritis nevertheless conceive in a normal manner, and give birth to a healthy child; and this not once only, but again and again.
As sterility due to mesometritis, von Grünewaldt classes the numerous cases in which sterility ensues upon a confinement in which the patient reports that inflammation followed delivery—or sometimes in which nothing abnormal was noticed. The results of local examination are negative: there is no displacement, no exudation or swelling, and no relevant affection of the endometrium. But the characteristic feature of these cases is, according to von Grünewaldt, that after her last full-time delivery, a woman has had a miscarriage or a premature delivery, and subsequently has been completely sterile. The degenerative process is at first partial, so that it does not prevent conception, but renders it impossible for the pregnancy to go on to full term; subsequently it extends throughout the mesometrium, and conception is no longer possible.
Cole of San Francisco regards as the most frequent cause of sterility ensuing upon a single delivery, subinvolution of the uterus, most commonly due to rising too early after delivery. He therefore considers it of especial importance after a first delivery that the physician should satisfy himself that no serious injury has been effected by the process.
Chronic endometritis is a very frequent cause of sterility: in the first place, the catarrhal swelling of the mucous membrane, which often extends from the os uteri externum to the ostium abdominale of the Fallopian tubes, offers an obstacle alike to the downward passage of the ovum and the upward passage of the spermatozoa; and secondly, in long standing cases, the large size of the uterine cavity and the smoothness of the surface of the atrophied mucous membrane, render the lodgment of the ovum in the uterus very unlikely. A further powerful obstacle to impregnation in cases of endometritis is offered by the profuse muco-purulent secretion which usually, though not invariably, accompanies that disease. This secretion, in some cases flowing freely over the surface of the membrane, but in others adhering to it with tenacity, whitish-yellow in colour, rendered cloudy by admixture of pus, or tinted red by admixture of blood, sometimes of a gelatinous consistency with a strongly alkaline reaction, contains globules of mucus, ciliated and cylindrical epithelial cells, pus corpuscles, bacteria and cocci,—and, if the endometritis is of gonorrhoeal origin, the gonococcus of Neisser. This secretion, when profuse and thinly fluid, pours out through the os, and sweeps away the semen; when tenacious and gelatinous, it fills up the dilated cervical canal above the constricted os uteri externum, and constitutes a powerful barrier to the upward passage of the spermatozoa; when purulent, it is destructive to the vital activity of the spermatozoa. The changes in the mucous membrane in cases of long standing endometritis whereby the uterus is rendered unfit for the implantation and incubation of the ovum, are the following. The epithelial cells, as usual in cases of continued catarrh, change in form, the ciliated cells disappear, and are replaced, first by cylindrical cells, later by polymorphic cells, approaching in type those of pavement epithelium. The mucous membrane is swelled, the vessels are dilated, there is hyperplasia of the glands, with a moderate amount of small-celled infiltration of the interglandular tissue (Fig. [83]). Ultimately the mucous membrane undergoes atrophy, its glands disappear, it comes to resemble a thin stratum of connective tissue.
Fig. [83].—Uterine Mucous Membrane in Endometritis. (After A. Martin.)
Thus, in severe and long-continued endometritis, the changes that occur in the uterine mucous membrane render the implantation of the ovum and the formation of normal decidua impossible; even if conception does occur, the fertilized ovum is speedily discharged. Frequently, in cases of endometritis, there is consecutive displacement of the uterus which acts as a contributory cause of sterility. When endometritis lasts a long time, proliferation of connective tissue in the uterine parenchyma also occurs, leading often to hypertrophy of the cervix, and to stenosis of the cervical canal. Since in so many different ways endometritis may give rise to sterility, the importance that must be attached to this condition is evident.
The great significance of gonorrhoeal infection in relation to sterility in women depends, not only on the changes this disease causes in the Fallopian tubes, leading to interference with the necessary contact of ovum and spermatozoon, but further, upon the occurrence of gonorrhoeal cervical and corporal endometritis, of perimetritis, and secondary parenchymatous metritis. Still, under appropriate treatment, the inflammatory changes consequent on gonorrhoeal infection are in many cases curable, and, after absorption of the exudations and restoration of the normal nutritive conditions of the tissues, conception may take place. Fritsch, who points out that in the woman infected with gonorrhoea, sterility ensues in a manner analogous to that in which it occurs in the male (for in the latter it is not the primary urethritis, the disease of the passage, but the secondary inflammation of the testicle that leads to sterility), states that he has observed cases in which beyond question conception has occurred, notwithstanding the existence of gonorrhoeal endometritis.