Predisposing Causes.—Almost all abnormal conditions, whether pertaining to the system or external to it, are more or less predisposing causes, whilst direct exciting causes are few; they may or may not be followed by the premature interruption of gestation; they tend to death and expulsion of the ovum, making it likely to occur whenever the exciting cause arises. We may say all those by which the occurrence of abortion is favored are predisposing causes: they are conditions under which we may expect its occurrence; and, knowing them, it is the duty of the physician to guard his patient. The classification is indefinite. Thus Naegele considers as predisposing causes anæmia, congestion local and general of the maternal system, neurotic influences; and as exciting causes—1st, those which tend to sever the amnion from the surrounding uterine structures; 2d, those which cause malnutrition, disease, and death of the embryo or foetus; 3d, those which directly arouse uterine contraction. Others consider diseases acute and chronic on the part of the mother, local and general, as well as diseases on the part of the father, predisposing causes, whilst traumatism and neurotic influences are considered as exciting causes. All are classifications based upon no strict foundation. I wish, however, to call attention to certain conditions which I look upon as predisposing to abortion: that is, a pregnant woman while under the influence of such condition, such cause, is more liable to abort upon the occurrence of some directly exciting cause. The existence of one or more predisposing causes does not necessitate abortion; pregnancy may continue without interruption if exposed to any of the conditions which we will term as exciting causes.
First. Climate.—We find abortion, both accidental and criminal, prevalent in certain countries and in certain districts, dependent upon climate—in the deltas and valleys subject to malaria, upon barren soil where food is wanting or where the work of woman is particularly laborious.
Secondly. Number and character of the population: this mishap is most common in large cities, where morals are lax, where the ill-fed poor are crowded into tenement-houses and the rich live in the whirl of social dissipation, or in thickly-settled regions where there is an intermingling of sexes, where women are neglected and ill-fed. I may here add an observation which truly shows the difference of locality. Both Playfair and Philippeaux3 claim that abortion is especially prevalent in the country. This may be true of the rural districts of England, France, and Germany, especially the latter military government, where it is in the country that young, able-bodied women do the hardest and most of the work, as is seen when passing through these regions in harvest-time. In America the very opposite is true, as in the country here abortion is most rare.
3 Annals Gynécologie, 1881.
Third. Certain periods in woman's life eminently predispose to abortion. There are those important epochs in woman's life during which her nervous system undergoes a severe strain wrought by those changes which are all-important to her existence. These are, first, in early married life, when intense hyperæsthesia exists due to changes wrought in the sexual system: the young wife is, moreover, exposed to injurious external influences, certain forms of traumatism; and secondly, toward the approach of the menopause, as the activity of sexual function and the uterine organ diminishes and the nervous system is undergoing those changes with periods of intense neurotic excitement which accompany the menopause. Finally, we may look upon the morbid conditions of the system, all unfavorable changes in the surroundings, as predisposing causes.
Exciting Causes.—We have seen that Naegele considers malnutrition and all causes which lead to separation of the ovum from its surroundings, and even uterine contractions, as exciting causes, whilst Spiegelborg considers hemorrhage so much so that to him the history of hemorrhage during gestation is the history of abortion. As exciting causes I consider uterine contractions and such conditions as directly lead to hemorrhage in the uterine or foetal membranes; but I cannot class either as exciting causes direct and primarily, both being merely sequents dependent upon some more remote cause. The varied importance of predisposing and exciting causes will be best appreciated if we but recollect the ordeals which a healthy woman may undergo—the direct exciting causes which may act upon her—and yet abortion not occur, provided no predisposing causes exist. Thus we have the well-authenticated statement of a pregnant woman being run over, the wheels of a physician's carriage passing directly over the abdomen, and yet abortion not following. I myself know of the attempts of a husband to produce abortion upon a willing wife by beating the abdomen, finally stamping and sitting down upon it, and yet not succeeding. I have the statement of a reliable physician as to the continuation of intra-uterine application of iodine and astringents to the cavity of a uterus supposed to be diseased, which proved to be pregnant, until the fourth month, and yet abortion not following. We know how women with criminal intent produce local injuries, even such as result in death, whilst the ovum remains undisturbed. These are cases in which no predisposing cause existed. On the other hand, the careless washing of the feet in cold water, a single effort at the wash-tub, a rapid drive, fright, a piece of bad news, coitus, the slightest nervous or physical disturbance, may produce abortion where predisposing cause sufficient does exist. We will here classify the exciting causes of abortion, in reference to the consequent treatment and the possibility of prevention, as maternal and foetal, dependent upon, acting by means of, the maternal system and organs or those of the ovum. Those dependent upon the mother are amenable to preventive treatment; not so those dependent upon the ovum.
A. Causes of spontaneous or non-criminal abortion:
1. Causes due to pathological changes in the maternal system, general and local. These are by far most important to the practitioner, as they are amenable to treatment. His attention should most especially be directed to—
a. General causes acting through the system. These are—
(1) Diseases acute and chronic;