A System of Midwifery

by Edward Rigby

Uterine souffle. The uterine sound, or souffle, may invariably be heard in one or other of the inguinal regions, and usually over a considerable portion of the uterus, extending anteriorly or along the sides of the organ; and according to the observations of Professor Naegelé jun.,[42] there is no part of the uterus, capable of being osculted, in which this sound may not be heard. He considers that the souffle, which is so uniformly heard in the lower parts of the uterus, especially in the inguinal regions, seems to be produced by the uterine arteries before they enter the uterus; these vessels, as soon as they arrive at the broad ligament, assume a different character, become larger than they were on branching off from their original trunk, and are much contorted before entering the parietes of the uterus. Dubois first pointed out the similarity which exists between the sound heard in the gravid uterus, and that of aneurismal varix, where there is a direct passage of blood from an artery into a vein: the sound in this latter condition is produced by the current of blood rapidly issuing from the dilated artery, and mixing with the slower flowing stream of the dilated vein. The circulation of blood in the dilated arteries of the uterus present a considerable resemblance, in many respects, to that of the above-mentioned disease.

That the uterine sound is not confined to that part of the uterus where the placenta is attached, as was supposed by Professor Hohl,[43] is proved by the fact that we can frequently hear it in two different and sometimes opposite parts of the uterus at the same time, which, if his opinion be correct, would indicate the presence of twins; and yet the result of labour has proved that the uterus has contained but one child, and that the placenta had neither been attached in the one or other of these situations. The very circumstance which we have already mentioned, of this sound being invariably heard in one, if not in both, of the inguinal regions, shows that it is independent of the vicinity of the placenta; nevertheless, it must be allowed, that as the uterine vessels undergo the greatest degree of development at this part, the sound will usually be at least as distinct here as in any other portion of the uterus.

The uterine souffle is the first sound which auscultation detects during pregnancy; it may be heard as early as the fifteenth or sixteenth week, but cases now and then occur where it has been even distinguished in the thirteenth or fourteenth week, and Dr. Evory Kennedy, has given some very interesting examples where he was able to hear it with certainty at the twelfth, eleventh, and even in one instance, at the tenth week. (Kennedy, op. cit. p. 80.) During these earlier periods, the sound is weaker, but extends over the whole uterus, from the diminutive size of which it can be heard most readily immediately above the symphysis pubis; in fact, there is every reason to suppose, that the uterine souffle might be detected at a still earlier period, if the uterus were at this time within reach of the stethoscope. As pregnancy advances, it becomes more distinct and powerful, and is occasionally so to a remarkably degree. During the latter periods of pregnancy, it frequently presents considerable modifications of tone, especially where there is general or local vascular excitement, as in cases of fever, or dispositions to hæmorrhage, where the vessels are usually distended, or where (Naegelé, op. cit. p. 86,) the placenta is situated near the os uteri, it assumes a piping, twanging sound of considerable resonance: the same is also observed where, either from the weight of the gravid uterus or any other cause, pressure has been exerted on any of the main arterial trunks: hence, as we shall show more fully when speaking of labour, a remarkable change is produced in the tone of the uterine souffle by the first contractions of that process. The causes of these modifications are not always very easily explained; we sometimes observe the souffle on the same side of the uterus vary rapidly in its degree of intensity, and occasionally even disappear for awhile without our being able to assign any satisfactory reason for such changes.

The uterine souffle taken by itself, although a very valuable sign of pregnancy, can scarcely be looked upon as one which is perfectly certain and diagnostic, since a similar sound may be produced by aneurism of the abdominal aorta and its large branches: there is much reason to think that the uterus, enlarged from other causes than that of pregnancy, and pressing upon the iliac arteries, will produce a similar sound. Professor Naegelé, jun., has also shown that the sounds of the patient’s heart may sometimes be heard very low in the abdomen, even as far as the ossa ilii, a circumstance which seems to have depended upon the sound being transmitted through the intestines distended with flatus. Where any of these causes of abdominal souffle have existed in connexion with suppressed catamenia, swelling of the breasts, &c., we might be liable to be deceived if we allowed ourselves to be entirely guided by this sound.

With regard to the fœtal pulsations, we find them generally beating at the rate of from 130 to 150 double strokes in a minute, and the age of the fœtus appears to have no effect upon their rapidity, for even at the earliest periods at which we can detect these sounds the rate of the pulsation is the same as at the full term of pregnancy.

Although Dr. Kennedy has in a few cases detected this sound even before the expiration of the fourth month, it will not in the majority be possible until a later period. “At the fourth month it frequently requires not only close attention, but considerable perseverence to detect the fœtal heart; and at this period it has occurred to us to examine patients whom there was strong reason to suppose pregnant, and after spending a considerable time in endeavouring to detect this sound, we have been on the point of giving up the search as hopeless, when it has been suddenly discovered in the identical spot that had before perhaps been explored without success.” (Kennedy, op. cit. p. 101.)

The sound of the fœtal heart is usually heard at about the middle point between the scrobiculus cordis and symphysis pubis, usually to one side, and that, generally speaking, the left. The extent of surface over which the sound may be heard varies a good deal, and depends, in great measure, on the distance which intervenes between the fœtus and stethoscope; hence, when the uterus is distended with a large quantity of liquor amnii, or when the uterine and abdominal parietes are very thick, it is heard over a much larger space, although with diminished intensity; on the other hand, when there is but little liquor amnii in the uterus, it is audible over a small portion only, but is remarkably distinct: this is peculiarly the case during labour after rupture of the membranes. The rapidity and strength of the fœtal pulsations appear to be entirely independent of the mother’s circulation; violent exercise, spirituous liquors, &c., which will raise her pulse to a considerable degree, have no influence whatever on the fœtal pulse. In cases of fever, where the mother’s pulse has ranged between 110° and 120°, and even higher, not the slightest change was observable in the sound of the fœtal heart; even in acute inflammatory affections, in pneumonia, pleurisy, where there was severe dyspnœa, and also in tubercular phthisis; in cases where the patient has been bled; in cases of menstruation during pregnancy; and even in severe flooding, and when the mother’s pulse has been greatly reduced, no perceptible change has been observed in that of the fœtus. (Naegelé, op. cit. p. 39.) Dr. Kennedy has observed some remarkable cases where the fœtal pulse appeared to vary in accordance with that of the mother (op. cit. p. 91;) but when we bear in mind the frequent changes in point of rapidity, &c., to which the fœtal heart is subject, independent of any thing of the kind in the mother’s pulse, and that similar changes are constantly observed in the child shortly after birth; and, moreover, that very considerable acceleration of the maternal pulse has decidedly no effect upon that of the fœtus in many well-marked instances, we cannot agree with him in supposing that a connexion of the sort to which he has alluded exists. The double pulsations of the fœtal heart can only be heard at one point of the uterus at a time, provided there be but one child; but if there be twins, then the sound is heard in two places at once. It has been supposed by some authors (Dubois) that the heart of the second child could not be distinctly heard until labour, when the membranes of the first child had ruptured. Generally speaking, both sounds can be heard pretty distinctly during the last weeks of pregnancy, one of them being low down on one side, and the other high up in an opposite direction. Although in some twin cases there is an evident difference of rhythm between the two fœtal hearts, still in many others they are so nearly synchronous as to be scarcely if at all distinguishable in this respect. Hence, therefore, from the known variable character of the fœtal pulse, it will be necessary that the sound of each heart should be ausculted at the same moment, minute for minute, by two observers, and thus the slightest appreciable difference between them determined.

Funic souffle. Dr. Kennedy has shown that, where a portion of the umbilical cord passes between the child’s body and the anterior wall of the uterus, or crosses any of its limbs or other projections, pulsations are heard synchronous with those of the fœtal heart; although not possessing the same characters. “In some cases where the uterus and parietes of the abdomen were extremely thin, I have been able,” says Dr. K., “to distinguish the funis by the touch externally, and felt it rolling distinctly under my finger, and then, on applying the stethoscope, its pulsations have been discoverable remarkably strong; and, on making pressure with the finger for a moment on that part of the funis which passed towards the umbilicus of the child, I have been able to render the pulsations less and less distinct, and even, on making the pressure sufficiently strong, to stop it altogether.” (Op. cit. p. 121.) In many cases where the umbilical arteries, by their convolutions round a limb, or by any other cause, are subjected to slight pressure, a distinct whizzing sound is produced, which is called by Dr. Kennedy the funic souffle.

The sound of the fœtal heart must be looked upon as a sign of the highest value in the diagnosis of pregnancy, since, however complicated and obscure the other symptoms may be, whether from co-existing disease, wilful deception, &c. if this sound be once heard unequivocally, the real nature of the case is satisfactorily established beyond all possibility of doubt.

Another sound in the gravid uterus has been lately noticed by Professor Naegelé, junior, which promises to equal that of the fœtal heart, as a certain diagnostic of pregnancy, and must be looked upon as a valuable addition to our means of ascertaining the truth in cases of this sort. The movements of the fœtus may be distinguished by the stethoscope at a very early period of pregnancy, long before they are perceptible to the hand of the accoucheur, and in many cases before the patient has been aware of them herself. According to Professor Naegelé’s observations, these sounds may usually be heard some little time before the fœtal heart is audible, and are sounds which can neither be feigned nor concealed: they can only be heard in the gravid uterus, and under no other circumstances.