A system of practical medicine. By American authors. Vol. 4

by Unknown

2. Abortion at the time most common, the third or fourth month: a, spontaneous; b, criminal and traumatic.

3. Later abortion—in the fifth and sixth months—and hydatiform mole.

The expulsion of the ovum during all periods of pregnancy is characterized by two inevitable symptoms—hemorrhage and pain. It is the time of appearance as well as the relative intensity of these symptoms by which the period of gestation at which the expulsion takes place is at once indicated. In early abortion the hemorrhage is excessive and precedes the pain, the pain being comparatively slight; in labor at term pain is the prominent symptom and precedes the comparatively slight hemorrhage, which does not appear until the pain has almost ceased, and labor is completed after the expulsion of the placenta. Expulsion of the ovum in intervening periods is marked by an approximation of symptoms, though the existing conditions which characterize individual cases greatly modify this typical course.

I have, for the sake of conveniently grouping the symptoms, accepted three periods which serve well to characterize the course which abortion is wont to take in the progressive months of pregnancy. Hemorrhage and pain are the never-failing symptoms—hemorrhage due to the separation of the membranes; pain in the earlier months is due to the dilatation of the rigid, unprepared cervix, which greatly preponderates over the pain which accompanies the expulsion of the comparatively small mass through the once-dilated passage. In the later months, the cervix being gradually prepared, the pain is almost altogether due to the increased effort which is necessary to expel the large mass of the ovum.

1. Early Abortion.—In the first and second months the ovum is small, the vascular development trifling; the decidua preponderates, being greatest in mass and in extent of its vessels; hence this is the most important part. The hemorrhage is considerable, due to the separation of the vascular and hypertrophied mucous membrane, the decidua. The ovum is very small and expelled with comparatively slight pain, the symptoms often resembling those of membranous dysmenorrhoea; no great dilatation of the os is even necessary.

2. In the third and fourth month, the period at which abortion both spontaneous and criminal is most common, the placental formation is inaugurated by the growth of the vascular tufts of the chorion; and it is now that the ovum in toto—or we may perhaps say the membranes, as they are by far the greater part of the ovum—assumes the most important rôle. The abortion is still inaugurated by hemorrhage due to the separation of the vessels, but the pain is greater, as the cervix must dilate more to admit the passage of this larger mass, and an expulsive effort as well is necessary to force the mass out. The greatest amount of pain is caused by the dilatation of the rigid, unyielding cervix, which fortunately remains in this undilatable state until after the period of viability of the foetus, and serves to a great extent as a check upon its more frequent expulsion.

3. Late Abortions.—Now the ovum and foetus are of pre-eminent importance; though the parts are still unprepared, hemorrhage continues to be the preliminary symptom, yet pain follows rapidly upon the inaugural flow, because the ovum is now so large that it cannot descend without dilatation: it must have advanced before abortion can progress to any extent, and the expulsive pains assume greater prominence on account of the increased size of the ovum; the symptoms of labor at term are approximated, and, as the placental formation is developed in the sixth month, pains may at times precede, certainly rapidly follow upon, the preliminary hemorrhage. It is now the placenta which plays the most important part, as in labor at term it is the foetus which is all-determining, upon which all the efforts of expulsion are centred; the membranes, amnion and chorion, are secondary, and the decidua, which was so important a feature in the first months, has by this time entirely disappeared as a factor in the act. The remaining shreds are partially adherent to the ovum, and in part passed slowly off with the lochial flow. Thus we see how the symptoms, at extreme periods so varying, approximate and interlace, and the various organs gradually yield in importance to newly-developing structures.

In the first period, then, the decidua is all-important, whilst the small and yielding ovum causes but little disturbance, not to mention the embryo. In the second period the membranes of the ovum are more important, and together form what is most erroneously termed the placenta in abortion. Then, as the placenta develops, this with the membranes predominates; finally, in labor at term the decidua, first all-important, has vanished as a factor of consequence, and the embryo, in the first stage a minimum, assumes such dimensions as to concentrate upon itself every effort of the obstetrician.

Pain, especially in the earlier months, is liable to be more excessive in primigravidæ, as the external os is closed, the cervix rigid, the time necessary for the expulsion of the ovum greater. In multigravidæ, with ordinarily more yielding and relaxed cervical tissues, the effort of the uterine muscle is concentrated upon the expulsion of the ovum from the cavity proper; and when it once passes the internal os a path is opened, and little or no force but that of gravity is often necessary to complete expulsion, whilst the cervical canal and external os offer formidable opposition in primigravidæ to the forcing out of the ovum, even though it has passed the os internum. A wide range of varying conditions naturally exists, due to the very different states of the cervical tissues: they may be relaxed in primigravidæ or firm and unyielding in multigravidæ, though the opposite is true in typical cases.