The second stage of labor is called that of expulsion, because in this stage the uterus contracts down together with the abdominal muscles to expel the child from the womb and the vagina into the world.  The duration of this stage in the first confinement is about an hour and a half.

The third stage of labor includes the time from the expulsion of the child till the coming away of the after-birth; the average length of this stage is from twenty minutes to half an hour.

The average length of time for the first labor is seventeen hours; and for subsequent labors from eight to eleven hours.

The bag of waters is the sac of membranes in which the child is inclosed.  It contains a liquid in which the child floats; the object of the water is to protect the child from sudden shocks or any kind of injury during pregnancy.  During labor this membrane with its contained water serves as a dilating wedge to assist in the opening of the womb, and it also protects the child from the direct contraction of the uterus upon it.  When the waters break prematurely, the labor is much longer and more tedious; normally this should not occur before the mouth of the womb is fully dilated.

The pains of the second stage of labor are of a bearing down character, and constantly increase in force and frequency; the climax being reached as the head passes through the vulvar orifice.

A child usually lies in the womb with the head downward; the reason of this is that there is more room in the upper part of the uterus, and as the small parts of the child as it is folded upon itself take up the most space, they occupy this position, while the head lies just above the pubes.  The normal position of the child is:  the head is flexed on the chest, the legs on the thighs and the thighs on the abdomen, and the hands are folded across the chest.  And so the child is usually born head first.

During the stage of expulsion the head of the child is forced down slightly during each pain, to recede a little during the intervals between the pains; in this way the vagina and its external orifice are gradually stretched so that the head of the child may pass through without tearing the parts.  If the head is allowed to pass through suddenly, or where the labors are rapid, as in the case of women who have given birth to several children, much mischief may be done by tearing the soft parts.

After the birth of the head there is a short interval of rest, when the shoulders are born; the rest of the body easily slips out; and with the expulsion of the after-birth the labor is over.

At the very beginning of labor the patient should be given a full warm tub-bath, and make an entire change of linen.  She will usually prefer to be dressed in her night-clothing, over which during the first stage she may wear a loose wrapper; a sterilized napkin should be worn over the vulva during this stage.  During the first stage, as a rule, the patient should not be confined to bed until the dilatation is well advanced; she is generally more comfortable if she is allowed to move around the room, and the pains are thereby advanced.