LABOR, DELIVERY, ETC.
After seven months of pregnancy the fœtus has all the conditions for breathing and exercising its digestion. It may then be separated from its mother, and change its mode of existence. Child-birth rarely, however, happens at this period: most frequently the fœtus remains two months longer in the uterus, and it does not pass out of this organ till after the revolution of nine months.
Examples are related of children being born after ten full months of gestation; but these cases are very doubtful, for it is extremely difficult to know the exact period of conception. The legislation in France, however, has fixed the principle, that child-birth may take place up to the two hundred and ninety-ninth day of pregnancy.
Nothing is more curious than the mechanism by which the fœtus is expelled; everything happens with wonderful precision; all seems to have been foreseen, and calculated to favor its passage through the pelvis and the genital parts.
The physical causes that determine the exit of the fœtus are the contraction of the uterus and that of the abdominal muscles; by their force the liquor amnii flows out, the head of the fœtus is engaged in the pelvis, it goes through it, and soon passes out by the valve, the folds of which disappear; these different phenomena take place in succession, and continue a certain time; they are accompanied with pains more or less severe; with swelling and softening of the soft parts of the pelvis and external genital parts, and with an abundant mucous secretion in the cavity of the vagina. All these circumstances, each in its own way, favor the passage of the fœtus. To facilitate the study of this action, it may be divided into several periods.
The first period of child-birth.—It is constituted by the precursory signs. Two or three days before child-birth a flow of mucus takes place from the vagina, the external genital parts swell and become softer; it is the same with the ligaments that unite the bones of the pelvis; the mouth of the womb flattens, its opening is enlarged, its edges become thinner; slight pains, known under the name of flying pains, are felt in the loins and abdomen.
Second period.—Pains of a peculiar kind come on; they begin in the lumbar region, and seem to be propagated towards the womb or the rectum; and are renewed only after intervals of a quarter or half an hour each. Each of them is accompanied with an evident contraction of the body of the uterus, with tension of its neck and dilatation of the opening; the finger directed into the vagina discovers that the envelopes of the fœtus are pushed outward, and that there is a considerable tumor, which is called the waters; the pains very soon become stronger, and the contraction of the uterus more powerful; the membranes break, and a part of the liquid escapes; the uterus contracts on itself, and is applied to the surface of the fœtus.
Third period.—The pains and contractions of the uterus increase considerably; they are instinctively accompanied by the contraction of the abdominal muscles. The woman who is aware of their effect is inclined to favour them, by making all the muscular efforts of which she is capable: her pulse then becomes stronger and more frequent; her face is animated, her eyes shine, her whole body is in extreme agitation, and perspiration flows in abundance. The head descends into the lower strait of the pelvis.
Fourth period.—After some moments of repose the pains and expulsive contractions resume all their activity; the head presents itself at the vulva, makes an effort to pass, and succeeds when there happens to be a contraction sufficiently strong to produce this effect. The head being once disengaged, the remaining parts of the body easily follow, on account of their smaller volume. The section of the umbilical cord is then made, and a ligature is put around it at a short distance from the umbilicus or navel.
Fifth period.—If the midwife has not proceeded immediately to the extraction of the placenta after the birth of the child, slight pains are felt in a short time, the uterus contracts freely, but with force enough to throw off the placenta and the membranes of the ovum; this expulsion bears the name of delivery. During the twelve or fifteen days that follow child-birth the uterus contracts by degrees upon itself, the woman suffers abundant perspirations, her breasts are extended by the milk that they secrete; a flow of matter, which takes place from the vagina, called lochia, first sanguiferous, then whitish, indicates that the organs of the woman resume, by degrees, the disposition they had before conception.