Causes. Premature expulsion may be induced by a great variety of causes, which may be brought under the two following heads: those which act indirectly, by destroying the life of the embryo, and those which act directly on the uterus itself. These various causes may be general or local; the process of nutrition for the growth and development of the embryo may be defective and scanty, from general debility or disease: hence, whatever depresses the tone of the patient’s health renders her liable to abortion by causing the death of the embryo. Thus, dyspepsia and derangement of the chylopoietic viscera; debilitating evacuations; depressing passions of the mind; bad or insufficient nourishment; intense pain, as in toothach; severe suffering from existing disease, especially where the health is much broken down by some chronic affection; syphilis, and febrile attacks, all act as indirect causes of abortion.[62] Salivation from mercury not unfrequently has a similar effect; in some instances, however, febrile affections appear to act much more directly, stimulating the uterus to powerful contractions and rapid expulsion of its contents. The symptoms which indicate the death of the child have already been detailed in the chapter upon that subject.
The period which may elapse between the death and the expulsion of the embryo varies exceedingly: in the early months the one usually follows the other pretty quickly, owing probably to the slight attachment of the ovum to the uterus; during the middle third of pregnancy the interval may be of considerable duration, and cases every now and then occur where the fœtus is retained, not only several weeks, but even some months after its death; whereas, during the latter third of pregnancy, expulsion follows the death of the child after a short interval, seldom exceeding two or three days; for now the weight of the dead fœtus speedily irritates the uterus to contraction, and, as has been observed by Smellie, the membranes, running gradually into putrefaction, and being now unable to bear the weight of the liquor amnii, burst, and expulsion soon follows.
Among the causes which act locally in inducing premature expulsion by first destroying the child, may be enumerated external violence applied to the abdomen, such as blows, falls, and other violent concussions; these act indirectly by producing separation of the ovum from the uterus, and thus destroying the life of the child. Under the same head may be classed all violent exertions, as lifting heavy weights, straining to reach something high above the head, &c. The mere act of walking, when carried to such an extent as to induce exhaustion, will suffice, in weakly delicate females, to bring on expulsion; sudden and violent action of the abdominal muscles, when excited by a half-involuntary effort to save herself from falling, or receiving any other injury, may produce a similar effect: if the fœtus be so young that its movements cannot be felt by the mother, she feels from this moment more or less pain in the pelvis, with a sensation of weight and bearing down; and this, in all probability, will be followed by a discharge of blood from the vagina: where pregnancy has sufficiently advanced for the motions of the fœtus to be perceptible, the mother will frequently feel them in an unusually violent degree for a short time immediately after the injury, and then they cease entirely.
Premature expulsion may also be induced immediately without the previous death of the child, by causes which directly excite the uterus to action: thus, various violent mental emotions, as rage, joy, horror, may act in this manner, although they may also act more indirectly; sudden exposure to cold, as sudden immersion in cold water, will occasionally produce it instantly. Irritation in the intestinal canal will directly excite uterine contraction; hence an attack of dysentery is frequently a cause of abortion, and we not unfrequently meet with patients who are liable to this affection in every pregnancy: a similar effect may be produced by the improper use of drastic purgatives, which irritate the lower bowels, viz. aloes, scammony, savin, &c.; or the uterus may, in some cases, be excited to contract from the peculiar action of secale cornutum. On the other hand, a loaded state of the bowels equally predisposes to abortion, by impeding the free return of blood from the pelvis. A state of general plethora acts in the same manner; and this is more particularly the case if it takes place at what would, in the unimpregnated state, have been a menstrual period; for, occurring in conjunction with the increased vascular action which prevails at these periods in the uterine system, it produces, as it were, an apoplectic state of the uterine sinuses, which form the maternal portion of the placenta; blood is extravasated between the ovum and uterus; their connexion is more or less destroyed, and the death of the fœtus becomes unavoidable: hence, in these cases the expulsion may result either from this latter circumstance, or from the uterus being irritated to contract by the effused blood between itself and the membranes.
In patients who have suffered from attacks of dysmenorrhœa in the unimpregnated state, the irritable uterus, when pregnant, is very apt to contract upon its contents and expel them. This usually happens at what would have been a menstrual period, and not unfrequently takes place so soon after impregnation as merely to be looked upon as an unusually severe attack, the little ovum having been imperceptibly expelled among the discharges. Under this head must be brought those cases of spasmodic affection of the uterus, which Dr. Burns has described, and where, from the diminutive size of the ovum, the case has rather resembled one of menorrhagia. Cases of abortion are also mentioned by authors where the uterus is stated to be incapable of undergoing the necessary dilatation and increase of size which pregnancy requires; but we are strongly disposed to refer them to the above head of great uterine irritability, as we neither know of any diagnostic marks which will enable us to detect this condition during life, nor are we aware of any physical condition of the uterus short of actual disease, to be detected after death, which can produce this inability.
The uterus may be also excited to expel the fœtus, without its previous death by local causes, as acute leucorrhœa, or other inflammatory affections of the vagina, by inflammation and other affections of the bladder, as calculus, &c. Too frequent sexual intercourse during the early months of pregnancy is peculiarly liable to excite abortion: this is especially observed among primiparæ of the better ranks, where, from luxurious living, &c., there is but little physical strength in proportion to the great irritability of the system: hence we find that a fifth, or even a fourth, of these females abort in their first pregnancies. In conclusion we may briefly state that the same circumstances which in the unimpregnated condition produce menstrual derangement and other disorders of the uterine system, now act as so many causes of abortion.
The sudden cessation of the breeding symptoms, with sense of weight and coldness in the lower part of the belly, flaccid breasts, pain in the back and loins, and discharge of blood from the uterus, are pretty sure signs of abortion: they are those which are “produced by separation of the ovum and contraction of the uterus,” (Burns;) the one is attended by hæmorrhage, the other by pain. Although these are two chief symptoms which characterize a case of threatened abortion, and although they must necessarily be present more or less in every instance where premature expulsion actually happens, still neither of them, either separately or conjointly, can be considered as a certain proof that the uterus will carry its contents no longer. Cases not unfrequently happen where patients have repeated attacks of hæmorrhage during the early months of pregnancy, and sometimes to a considerable amount, without any apparent disturbance to the process of gestation, and are delivered of a living healthy child at the full term: on the other hand, we have known instances where the pain of the back was severe, and where, on assuming the erect posture even for a minute, the sense of weight and bearing down in the lower part of the abdomen was so great as to make the patient fear that the ovum was on the point of coming away; still even these threatening symptoms have gradually subsided, and the pregnancy has continued its natural period. Puzos considered that neither pain nor hæmorrhage were necessarily followed by expulsion. (Mém. de l’Acad. de Chir. vol. i. p. 203.) When, however, both occur together, and to a considerable extent, the case must be looked upon as one of at least doubtful if not unfavourable termination. Where pain comes on at regular intervals, with hardness of the uterus, and dilatation of its mouth, this is a serious symptom, for it shows that the uterus will no longer retain its contents, but is evidently preparing to expel them.
The part of the ovum at which the separation of it from the uterus has taken place, not only determines which of the above symptoms will appear first, but also the probability of expulsion. “When a considerable separation takes place, as must be the case when it commences at the upper parts of the uterus, pain will more likely occur than when it happens near the neck; hence we sometimes have pain before the blood issues externally. The uterus in this instance suffers irritation from partial distension from the blood insinuating itself behind the ovum; contraction ensues; the blood is thus forced downwards, and is made to separate the attachment between the ovum and the uterus in its course, until it finally gains an outlet at the os tincæ. In consequence of the uterus being excited to contraction, the friendly coagula which may have formed from time to time are driven away, and the bleeding each time is renewed and accompanied most probably with increased separation of the ovum, until at last from its extent the ovum becomes almost an extraneous body, and is finally cast off. Hence a separation at or near the os uteri will not be so dangerous, and in all probability there will be hæmorrhage without pain, which is the contrary when it takes place near the fundus.” (Dewees, Compend. System of Midwifery, § 981, 982.) The pain during the abortion is sometimes exceedingly severe, and not unlike that of dysmenorrhœa: this is probably owing to the violent contractions of the uterus, which are required to dilate the os and cervix before the ovum can pass: they are frequently attended with nausea, vomiting, and fainting, and sometimes with more or less general fever and local inflammatory action; the pain is generally attended with much irritability of the bladder, and frequent desire to pass water; the pulse is mostly quick and small, and where there is arterial excitement, it is sharp and resists the finger.
Treatment. The treatment of premature expulsion consists in, 1, that which is intended to guard the patient against its occurrence, or prophylactic; and 2, in that which is required during an attack.
A knowledge of the various causes of premature expulsion will materially assist us in the prophylactic treatment; under all circumstances, even where there is not the remotest fear of such an accident coming on, it is nevertheless highly important to pay strict attention to the state of the stomach and bowels, for these are almost always more or less influenced by the presence of pregnancy; the vomiting and sickness must be relieved in the manner already pointed out under the chapter on the Treatment of Pregnancy; the bowels, if constipated, must be moved by the mildest laxatives, such as castor oil, Confect. sennæ, or a Seidlitz powder; and thus all sources of irritation in the primæ viæ prevented as far as possible. The patient must carefully avoid every thing which may excite the circulation, such as violent affections of the mind, rich indigestible and stimulating food, violent exertion, &c. The diet should be light, nourishing, and moderate; heavy meals must be forbidden, and especially suppers; she should keep early hours, take gentle and regular exercise, and in fact, endeavour by every means in her power to raise her health to a full degree of tone and regularity. In those patients who have already miscarried in their previous pregnancies, these precautions must be enforced with double vigilence; for the system becomes exceedingly irritable, and the uterus soon acquires, as it were, a habit of retaining its contents only to a certain period, and then prematurely expelling them. When this is the case, it becomes exceedingly difficult, and is often actually impossible, to make it carry the ovum to the full term of utero-gestation, and, despite of the greatest care, the symptoms of premature expulsion will come on at about the same time at which they occurred in former pregnancies, and sometimes to the very same week.