A System of Midwifery

by Edward Rigby

First contractions. The first contractions of the uterus (in a state of health) are so slight as scarcely to be noticed by the patient: they create a sensation of equable pressure and general tightness round the abdomen, and during the contraction the uterus feels somewhat firmer, but they are neither attended with pain, nor do they appear at first to have any effect upon the os uteri; these precursory contractions generally come on a day or two before actual labour commences, and sometimes are felt at intervals for one or two weeks. Where the uterus has been exposed to any source of irritation, and especially where there is a disposition to rheumatic affection of this organ, they may produce much suffering and give rise to one form of what are called false pains, hereafter to be described. “The first contractions, says M. Leroux (Sur les Pertes de Sang, § 41.,) are feeble, and communicate no sensation to the patient; in order to discover them we must hold our hand upon the abdomen, and if we feel the globe of the uterus raise itself and become hard, this is a true contraction. These contractions gradually increase until they excite pain: but pain is not essential to a contraction; it depends on the distension and compression of the nerves produced by the resistance of the body upon which the uterus acts, and increases in severity in proportion to the degree of resistance and contraction.”

In proportion as the lower part of the uterus descends into the cavity of the pelvis, so does it exert a degree of pressure on the neighbouring parts; the capacity of the bladder and rectum is diminished; and being therefore unable to contain the usual quantity of urine and fæces, and being probably rendered more irritable by the pressure above-mentioned, the patient experiences frequent calls to pass water and evacuate the bowels, which is sometimes effected with considerable difficulty: in some instances she is obliged to lean forward, or support the abdomen, in order to take the weight of the child off the neck of the bladder before she can empty it: the same cause occasionally requires the use of the catheter, and sometimes renders the introduction of it a matter of considerable difficulty.

As these various changes make their appearance, the patient becomes restless and anxious; she cannot remain long in the same posture; the slight precursory contractions which have been just described, are becoming stronger, and begin to produce a sensation of pain; the os uteri (in primiparæ) opens somewhat, its edge at first is exceedingly thin, and feels almost membranous; by degrees however it swells, grows thick and cushiony, and is now more dilatable.

Action of the pains. The os uteri does not dilate merely by the mechanical stretching which the pressure of the membranes and presenting part exert upon it; it dilates in consequence of its circular fibres being no longer able to maintain that state of contraction which they had preserved during pregnancy; they are overpowered by the longitudinal fibres of the uterus, which, by their contractions, pull open the os uteri equally in every direction.

The vagina also swells and grows more cushiony, and this is followed by a copious secretion of colourless and nearly inodorous mucus. “The more albuminous it is the better, and it is always a good sign when lumps of albuminous matter come away from time to time; the thicker, softer, and more cushiony the os uteri is, the more mucus does it secrete.” (Wigand, Geburt des Menschen, vol. ii. p. 292.) The thin hard os uteri does not dilate, its fibres are all in close contact, and like a well-twisted cord will not yield; whereas, when they are separated from each other by the swelling of the os uteri, they easily yield to the dilating force which is applied to them. Besides serving the purpose of lubricating the passage, the secretion of mucus is of great importance as a topical depletion, for, by thus unloading the congested vessels, they diminish the vascularity and heat of the part, and render it more capable of dilatation. “If, on the other hand, the entrance of the vagina is small, the neighbouring parts cool, dry, inelastic, and as if tightly stretched over the bones; if the finger, in spite of being well oiled and carefully introduced, produces pain upon the gentlest attempt to examine, we may expect a tedious and difficult labour.” (Op. cit. p. 190.)

The patient is now no longer able to conceal her pains when they come on. If she be in the act of conversing she stops short, and remains silent until the severity of the pain is over; if she be walking about her room she is obliged to stand still for the time, and rest against or hold by something until the pain has gone off. The true labour pains are situated in the back and loins; they come on at regular intervals, rise gradually up to a certain pitch of intensity, and abate as gradually; it is a dull, heavy, deep sort of pain, producing occasionally a low moan from the patient: not sharp or twinging, which would elicit a very different expression of suffering from her.

Auscultation during the pains. “If we direct our attention to the changes of tone which the uterine pulsations present during auscultation, we shall find them generally stronger, more distinct and varied in tone during labour; and this is especially the case just before a pain comes on. Even if the patient wished to conceal her pains, this phenomenon, and more especially the rapidity of the beats, would enable us to ascertain the truth. The moment a pain begins, and even before the patient herself is aware of it, we hear a sudden short rushing sound, which appears to proceed from the liquor amnii, and to be partly produced by the movement of the child, which seems to anticipate the coming on of the contraction: nearly at the same moment all the tones of the uterine pulsations become stronger; other tones, which have not been heard before, and which are of a piping resonant character, now become audible, and seem to vibrate through the stethoscope, like the sound of a string which has been struck and drawn tighter while in the act of vibrating. The whole tone of the uterine circulation rises in point of pitch. Shortly after this, viz. as the pain becomes stronger and more general, the uterine sound seems as it were to become more and more distant, until at length it becomes very dull, or altogether inaudible. But as soon as the pain has reached its height and gradually declines, the sound is again heard as full as at the beginning of the pain, and resumes its former tone, which in the intervals between the pains is as it was during pregnancy, except somewhat louder. This is the course of things if the pain be a true one, and attain its full intensity: where the pains are false or irregular it is very different; the uterine sound either remains unaltered, or increases only for an instant, or its seeming increase of distance, as above mentioned, is not observed.” (Die Geburtshülfliche Exploration, von Dr. A. T. Hohl, erster theil, s. 105.)

Effect of the pains upon the pulse. It is curious to observe the effect which a regular pain has upon the rapidity of the mother’s pulse; as the former comes on and goes off, so does the other increase or diminish. “The increasing rapidity of the pulse announces the commencement of the pain; it rises and attains its summum with it; and as the pain subsides so does the pulse gradually resume the rate which it had during the intervals; a similar ebb and flow may be heard in the uterine souffle. The more regular the pain is, and the more distinctly it rises to its full extent, the more marked, regular, and distinct, is this change in it. We may also invert the order of things, and say, the more distinctly the rapidity of the pulse comes on and announces the pain, the more regularly it rises and attains a certain height, which it maintains, and then gradually subsides; in like proportion will the pain be more perfect, attain its full extent more completely, and act more efficaciously upon the regular progress of the labour. Where however the rapidity of the beats subsides before it had scarcely begun to increase, the pain is too weak; or where the rapidity rises by sudden starts, the pain is a hurried one; and in either case its effect will be imperfect.” (Hohl, op. cit. vol. i. p. 108.) In order that we may ascertain these changes correctly, we ought to note the rapidity of the pulse during each successive quarter of a minute as directed by M. Hohl; thus, in a pain which lasts two minutes, the increase and diminution in the rapidity of the pulse may be as follows, 18. 18. 20. 22.; 24. 24. 22. 18. As labour advances it increases, so that shortly before the birth of the child we shall find that what was the rate of the pulse during the height of the pains at the beginning is now the rate of it during the intervals.

Symptoms to be observed during and between the pains. When a pain comes on, the uterus grows hard and tense; if the fundus be somewhat to one side, as is not unfrequently the case, it now gradually moves, so that the median line of the uterus corresponds with that of the patient’s body; the various prominences of the child are no longer to be felt, the whole is now firm and unyielding; the os uteri is put tightly upon the stretch, the membranes which were loose become tense and are firmly pressed against it, and the presenting part is rendered indistinct: as the pain gradually subsides, the uterus becomes softer, and yields to the pressure of the hand; the different parts of the child which project, as also its movements, can now be felt more distinctly; the patient is free from pain, and feels herself in an agreeable state of tranquillity, which is frequently attended by a short refreshing doze; the os uteri, which has become somewhat more dilated during the last pain, is now soft and loose, so that we can hook the finger into it and move it about; the tight bladder of membranes becomes relaxed and flaccid, and retracts more or less into the uterus, so that we shall now be able to introduce the finger into the os uteri and feel the presenting part through the membranes; while the presenting part of the child, which during the pain was fixed, can be moved somewhat by the finger.

Characters of a true pain. In examining the course of a true pain we shall find that the contractions of the uterus do not begin in the fundus, but in the os uteri, and pass from the one to the other. (Wigand, op. cit. vol. ii. p. 197.) Every pain which commences in the fundus is abnormal, and either arises from some derangement in the uterine action, or is sympathetic with some irritation not immediately connected with the uterus, as from colic, constipation, &c. We very seldom find that a contraction of the uterus, which has commenced in the fundus, passes into the cervix and os uteri, and becomes a genuine effective pain; usually speaking, the contraction is confined to the circumference of the fundus, without detruding the fœtus at all. When a genuine pain comes on, so far from the head being pressed against the os uteri, it at first rises upwards, and sometimes gets even out of reach of the finger, whilst the os uteri itself is filled with the bladder of membranes: if it had commenced in the fundus instead of the inferior segment of the uterus, so far from the head being drawn up at the first coming on of the pain, it would have been forcibly pushed down against the os uteri. In the course of a few seconds the contraction gradually spreads over the whole uterus, and is felt especially in the fundus; the head which had been raised somewhat from the os uteri is now again pushed downwards to it, and seems to act as a wedge for the purpose of dilating it; it is not until the whole uterus is beginning to contract that the patient has a sensation of pain. We may, therefore, consider that a genuine uterine contraction consists of certain phenomena which occur in the following order: first, the os uteri grows tight, and the presenting part rises somewhat from it; then the rest of the uterus, especially the fundus, becoming hard, the patient has a sensation of pain, and the presenting part of the child advances. The period of time necessary for all these changes varies not only in different individuals, but in the same individual in different labours, and in different stages of the same labour.