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.