The actual frequency of miscarriage is generally underestimated. Patients themselves often do not know what has really happened. When the accident occurs a few days after conception, bleeding may be its only evidence, which will almost certainly be misinterpreted as an irregularity of menstruation; and professional advice will not often be thought necessary. Moreover, in other cases in which the true situation is appreciated the patient does not feel sick enough to seek medical assistance. If it were possible to include in the statistics all these cases as well as those which are concealed because intentionally provoked, the frequency with which pregnancy is interrupted during the early months would be found somewhat greater than is usually supposed.
If we omit the miscarriages which occur within the first few weeks of pregnancy, and which consequently often escape detection, the majority of cases fall within the second and third months. After the fourth month has passed, the probability of such an accident, though not excluded, is greatly diminished. Some statistics recently published by Taussig make this clear. In a series of several hundred cases of miscarriage, one hundred and fifty-seven instances occurred in the second month, two hundred and twenty-two in the third month, seventy-three in the fourth month, thirty-seven in the fifth month, and five in the sixth month. This order of frequency might be anticipated from the anatomical conditions which prevail during the early months of pregnancy, since the attachment of the embryo to the mother is at first relatively insecure, but gradually grows firmer, and becomes as secure as it ever will be by about the fifth month.
It is noteworthy that miscarriage occurs much less commonly in the first than in subsequent pregnancies. Indeed, a somewhat greater liability to the accident with each succeeding pregnancy goes far toward explaining the greater frequency of miscarriage among women who have passed the thirty-fifth year than among those who are younger.
CAUSES AND PREVENTION.—We have seen that the proportion of pregnancies which end in miscarriage is quite formidable. But this should not be true, as the accident is frequently preventable, and many of these accidents could be avoided by the cooperation of patients. As self-denial and personal inconvenience are often essential, it is only fair to explain their value. Furthermore, the, patient who appreciates the reason for certain directions the physician gives becomes responsible to herself, and is much more likely to carry them out than is one who is cautioned without receiving a satisfactory explanation. At best, however, the advice which the physician is able to offer will be imperfect, for it must not be imagined that everything is known concerning the causation and prevention of miscarriage. While our knowledge is so imperfect we must be content to make the most of what we possess. It must be added that no suggestion such as can be given here will enable anyone to dispense with her own medical adviser. On the contrary, if there is reason to fear miscarriage, the prospective mother should be encouraged to seek his counsel as early as possible. Aside from the hygienic measures which she may learn to carry out for herself, various drugs are often of great value in preventing miscarriage. Since these are not applicable to all cases, they should be employed only upon medical advice.
Very early miscarriages may be explained by the loose attachment of the ovum during the first six weeks of pregnancy. This tiny, living sphere, it will be recalled, reaches the womb a few days after conception, and adheres to the uterine mucous membrane. At first, however, its roots are short and delicate, and not so capable of anchoring the ovum as they become later. It is only toward the end of the eighteenth week that the union between the womb and its contents becomes firm.
From what we have learned in Chapter II regarding the anatomical conditions in the early days of pregnancy it is obvious that we need not be greatly surprised at the frequency of miscarriage. On the other hand, it must not be forgotten that there are many natural safeguards against accident: to mention only one, the uterus is ingeniously swung in the abdominal cavity so as to afford a large measure of protection against mechanical shock. Usually, the provisions nature has made are sufficient to resist forces from without which tend to dislodge the ovum. Now and then it happens that the most irrational acts will not interrupt pregnancy; indeed, they often seem particularly inert when practised intentionally.
Fear of loosening the ovum from its uterine attachment prompts experienced women to caution prospective mothers against any kind of sudden or violent effort. Their advice, however, is often needlessly alarming; a great many traditional precautions lack a reasonable basis. Thus, no harm can possibly result from sleeping with the arms above the head; nor from "over-reaching," as when hanging a picture, though a fall under such circumstances might be dangerous.
Patients who have been warned by one experience should always be on their guard if they would avoid repeated miscarriages; others need only lead a sensible, hygienic life, a matter we have already discussed in the chapters dealing with the care of the body and the way to live. For the sake of emphasis, I may here repeat that no prospective mother should become fatigued from any cause; sweeping, moving heavy furniture, lifting heavy articles, and running a sewing machine are not to be attempted. But household duties which do not require strong muscular effort are better assumed than not.
Amusements which may cause jolting, or expose one to the danger of falling, involve some risk of miscarriage. Short rides in a carriage or an automobile over smooth roads are free from objection. Railway- travel and sea-voyages are not advisable in the early months; after the eighteenth week they may be undertaken with a greater degree of safety, provided comfortable accommodations are assured, and the patient has never had a miscarriage.
A few physicians, even at present, attribute the interruption of pregnancy to strong emotions, including intense joy or sorrow, anger, fright, or even jealousy. Without denying altogether the possibility of such an influence, we may be sure that its importance is greatly exaggerated. It is not unusual to see patients who are able to recall a mental shock of some kind shortly before the miscarriage occurred; nevertheless, in such cases diligent search will usually reveal a physical cause for the accident.