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

by Unknown

The period scientifically the first, and the most interesting stage of development, during the first three or four weeks, when segmentation takes place and the form is moulded, we shall in no way consider. The ovum may then be cast off, perhaps at a succeeding monthly period, unbeknown to any one, perhaps not even to the unconscious mother: certainly the services of an accoucheur are not called for. In the third or fourth week it is a delicate cyst-like body of the size of a hazel-nut, some half an inch in diameter, surrounded by its translucent chorion, and is crushed in the passages or disappears amid the clots of blood of an apparently profuse menstrual flow. The following periods of development are, however, of practical importance, as they will serve diagnostic purposes, as well as an understanding of the appearance of the ovum and the symptoms accompanying miscarriage.

The ovum during the first months of pregnancy is an oval cyst-like body surrounded by the chorion, the shaggy tufts of which give it a characteristic readily-recognized appearance. Enclosed within is the delicate transparent amnion, and the embryo, attached to the navel-string, floating in the clear liquor. At six weeks the size of the ovum is likened to that of a pigeon's egg; at eight or nine weeks to that of a hen's egg, perhaps 1½ inches in length; at the twelfth week, to that of a goose-egg, some 4 inches in length. In the second month the ovum forms a bulging prominence in the uterine cavity, usually toward the fundus, and reveals all the parts recognized at term with the exception of the placenta and the still distinct umbilical vesicle: its surface is covered by the tufts of the chorion and surrounded by the decidua reflexa. In the third month it is so far developed as to completely occupy the uterine cavity, as yet but slightly adherent, approximated, a part of it agglutinated to the uterine mucosa, to the decidua serotina, the greater mass of the chorion being in no way adherent to the surrounding reflexa. The tufts of the chorion begin to sprout and develop more fully at its point of contact with the uterine wall above the decidua serotina, whilst upon the remaining and greater portion of its surface their growth ceases, and as the membrane distends the delicate filaments gradually disappear. At the end of the third month, in the fourth month, the tufts of the chorion have sufficiently developed in its adherent portion to form the rudimentary placenta, and at the end of the fourth month this is developed still more—has become more dense and large, whilst the remaining portion of the membrane appears smooth and barely shows a few scanty remnants of the once-shaggy tufts.

The growth of the ovum now rapidly outstrips that of the uterine cavity; the membranes are pressed more firmly against its walls, approximated to the decidua vera, but not by any means agglutinated. In the sixth month the placenta has been thoroughly formed—it has become dense and large, the foetal membranes beginning to agglutinate to the uterine wall, and the conditions existing at term are rapidly approached. The embryonic tissues are supplied with the necessary nutriment by endosmosis from the surrounding maternal structures during the first months; the entire surface of the chorion absorbs, whilst this function is delegated to the proliferating villi as they develop and agglutinate with the decidua serotina, foreshadowing the activity of the placenta by which the foetus is nourished to term.

Practically, the most important period in the development of the ovum is the one most dangerous to its existence—in the third and fourth month, that period of intense activity of chorion and decidua, the time of the formation of the placenta, when hemorrhage is likely to occur from the congestion of the vessels so necessary to the nutrition of the rapidly-growing and delicate tissues. Nutriment is no longer merely absorbed by the succulent embryonic cells of the ovum from the tissue in which they are in contact, but the embryo is forced to seek sustenance through those now fully-developed tufts of the chorion—from the proper site, the decidua serotina and the surrounding vessels—directly from the uterine structures. If hemorrhage interferes or disease prevails, the healthy growth of the ovum is checked, and a morbid development ensues, to result sooner or later in death of the embryo and expulsion.

The embryo in the early months of pregnancy is small as compared to the size of the sac, the membranes, liquor amnii, and navel-string; at the end of the fourth week the embryo measures from ¹/3 to ¼ of an inch in length; at the end of the eighth week, from ¾ to 1 inch: the arms and legs become visible, the umbilical vesicle, though reduced in size, still exists; the small body with large upper extremity is pendent from the short, thick navel-string. At the end of the twelfth week the embryo measures from 2 to 3 inches in length; fingers and toes can be distinctly seen; mouth and nose are also recognizable. At the end of the sixteenth week, the fourth month, the embryo measures some 4 to 5 inches in length; sex can be distinguished; the head assumes shape, but it is still immense in size, perhaps an inch in length; the features of the face are all formed. At the end of the twentieth week, the fifth month, there is no longer doubt as to sex; the nails, which were previously visible, have become distinct; the soft, woolly lanugo begins to develop; hair may be noticed upon the head; motion, inaugurated weeks before, is felt by the mother. Toward the end of the sixth month, in the twenty-fourth week, the embryo is some 12 inches in length. As has been before stated, with the cessation of the development of individual organs and parts growth in size becomes more rapid. As this was less in the earlier months, it is now very marked. With the seventh month, as the foetus becomes viable, it is some 12 to 14 inches in length, weighing 2 to 3 pounds; the body is covered with lanugo; the hair on the head becomes quite marked; the papular membrane disappears.

It is well to bear in mind the leading features in the development of the uterus, decidua, and the ovum, and more particularly its membranes, as a guide in the treatment, that we may recognize the parts expelled and know what remains to be removed—as an aid in diagnosis, that we may properly judge the conditions, whether healthy or morbid, and post-abortum, when we may be forced to determine by the corpus delicti, as the all-important evidence in criminal cases, as to the duration of pregnancy and the causes which led to its termination.

ETIOLOGY.—Causes of Abortion.—Interesting as the etiology of disease is to the inquiring mind, to the progressive physician it is of great practical importance as well; and this is eminently true of the causes leading to abortion. More so of (A) spontaneous or accidental abortion, though by no means to be neglected in (B) criminal abortion. Etiology is important in both, as it is a knowledge of cause alone which can lead to prevention, that most valuable of all methods of treatment, and in criminal abortion to detection, thus indirectly to the prevention of recurrence.

A. Accidental or Spontaneous Abortion, or Abortion as the Result of Natural Causes.—The etiology of non-criminal abortion is indispensable to the practitioner, as it is this alone which will enable him to prevent its occurrence and recurrence, thus leading to the preservation of the lives of mother and child, doing away with the danger and suffering of actual treatment, and frequently serving as a guide in the latter. We will meet with some difficulties in our endeavor to analyze these causes, as they are so varied in their nature and differ so greatly in the medium through which they act. There are causes predisposing and exciting, local and general, internal and external, and causes which depend upon father, mother, and ovum. The direct dependence of treatment upon the exciting causes seems to necessitate a simple and practical delineation of the etiology of abortion. A direct reference of the cause to the offending organ is understood most readily, and will point most directly to the necessary measure of relief; hence we will consider such causes as spring from or act through mother and child—more properly, the maternal system and its individual organs on the one hand, and the ovum and its parts upon the other. We cannot, however, pass by these without giving a thought to such causes to which great importance is attached by many, and which it is best to consider separately.