These accidents are so intimately connected with flooding, that many writers always treat of them together, considering the flooding merely as the most frequent cause and symptom of miscarriage or abortion. In speaking therefore of the immediate causes of premature expulsion of the fœtus, we place hemorrhage first, and the causes before enumerated which produce that as being its most frequent remote ones.
A full habit, with tendency to local congestion, seems to predispose a female very much to miscarriage; every one so constituted should carefully avoid luxurious living and an inactive life. Violent bodily exertion, falls, or blows, or strong mental excitement are most usually the immediate causes, though with some it will come on spontaneously without any such exciting agencies. Some females will miscarry many times in succession, and always so near the same period, that they can tell to a day or two when it will happen. It seems to become a habit of the womb with them to contract at that particular time, and the only way to break through the habit is for them to avoid becoming pregnant for some considerable time, say two or three years after, they may then go the full time, but will seldom do so if they conceive immediately after having miscarried. In some persons miscarriage is caused by a too eager gratification of certain desires; but in others it may arise from the opposite cause.
There is a disease of the womb also by no means unfrequent, though but little understood, which undoubtedly causes much miscarriage, and that is Rheumatism of the Womb! This mostly exists before the pregnancy however, and should be then treated according to the plan laid down in my "Diseases of Woman."
Miscarriage also arises in many females from a rigid state of the muscular fibres of the womb, which not relaxing sufficiently to allow that organ to expand become irritated by the pressure they experience, and begin to contract. This contraction of the womb of course soon leads to the expulsion of its contents, the same as in real labor. Women with their first children are more liable to miscarriage than others on this account, the womb not having become habituated as it were to the necessary relaxation.
And this is the reason also why some females, after suffering from this accident many times in succession at last escape it. In general they miscarry early the first time, from the womb not relaxing sufficiently, but go a little longer the next time, and longer still the next, and so on till they reach the full period. The fibres of the womb have gradually become accustomed to relax, and have borne the irritation longer and longer each pregnancy, till at last they have forborne to contract till the proper time. I knew one female who miscarried twenty-one times in succession, getting gradually nearer to the full period each time, till at last she reached nine months, and was rewarded with a living child.
Sometimes the accident may be produced by a uterine tumor, by a great quantity of water in the womb, or even by there being more than one child, because in either of these cases there is required more room than ordinary; and of course from the greater expansion required, the liability is increased. Various womb diseases may also be mentioned as causes, or adhesions of its walls or ligaments to the walls of the abdomen, and also a diseased state of the placenta. The pressure of corsets and tight dresses also not unfrequently lead to the same result. Some general diseases undoubtedly often cause miscarriage, such as measles, jaundice, scarlet fever, consumption, and probably many others, particularly those in which the quality of the blood is much altered, or the nervous power much exalted or depressed. Convulsions have already been mentioned as being frequent causes of miscarriage, and all strong mental or moral impressions. Indeed these last causes operate more than is suspected, and make it necessary for a pregnant female to be kept as calm in her mind as it is possible for her to be. I have even known one to miscarry from a fright in a dream.
It is also a fact, though not generally known, that there are certain diseases of the father that may produce miscarriage, and unfortunately they are of that kind that often remain for a long time in the system without much external manifestation, so that many persons think they are perfectly free from them even while they are working such mischief.
The death of the child also is sure to produce miscarriage, and this may result from various causes, such as external injuries and violence, or from remaining too long in the warm bath and thereby causing congestion of blood in the womb. Small pox and syphilis in the mother may also cause the death of the child, though not always. Many having been born at full term with these diseases upon them.
In general the fœtus is expelled very soon after it dies, but occasionally it is retained for a considerable time, and may not pass away till it is completely decayed. It has even been known to become almost fluid, and several months elapse before it was entirely expelled. Most women know when it dies, by its seeming to fall down to the bottom of the abdomen, like a dull weight, and also by its feeling very cold. Very often, however, there is no indication of its death whatever. M. Chailly mentions a case where the embryo died, probably when about fifteen days old, but the placenta continued to grow, and the lady was delivered when about six months and a half gone of the dead embryo, only about a quarter of an inch in length, though the after-birth was nearly large enough for one of the usual size. In this case it had died but not decayed, and remained in the womb six months and a half. In cases of twins also, one will sometimes die at an early period, but remain till the other is born at full term.
The growth of the placenta over the mouth of the womb, and shortness of the chord, have already been referred to as causes both of flooding and miscarriage; and to these may be added monstrous or deformed fœtuses, which rarely reach the full term.