Position of the Womb.—­At four months the top of the womb has risen above the pelvic brim bone in front; at five months, it is midway between the bone (pubic) and the navel; at six months, it is at the navel; at seven months, it is four fingers breadths above the navel; at eight months, it is midway between the navel and the bottom of the breast bone; at nine months, it is to the breast bone; from the middle to the end of the ninth month, the top of the womb sinks to about the position occupied at the eighth month.

Twins occur about once in ninety to one hundred and twenty, triplets once in one thousand eight hundred and seventy-five, and quadruplets once in three hundred and seventy-one thousand one hundred and twenty-six pregnancies.  The causes are unknown.  Twin conception is more common in women who have borne children, and more so in the elderly than in the young, first bearing women (primiparae).

Sex.—­Children from the same ovum (egg) are always of the same sex.  Of twins in general, more than one-third are males, less than one-third are females, and in the remaining one-third both sexes occur.  The after-birth is always, at least at first, double.

Diagnosis.—­In twin pregnancy the symptoms and disorders of pregnancy are apt to be exaggerated, and watery swelling above the pubic bone is almost always present in the latter months.  The abdomen is larger and broader and there may be a depression dividing the abdominal wall in two spaces.  The womb is much distended and the walls are thin.

Hygiene of pregnancy.—­In pregnancy the dividing line between health and disease is often so shadowy that every care should be given the pregnant woman, not only that she shall escape dangers that may come, but that the future health of the coming baby may be safeguarded.

The care taken in pregnancy therefore should include attention to clothing, food, exercise, rest, sleep, functions of all excreting organs, the breasts, nervous system and the mind.

[520 Mothers’ remedies]

Clothing.—­This should be worn loose.  The heavier garments should not be held by the waist but suspended from the shoulders.  Flannels, if possible, should be worn next the skin excepting, possibly, during the warmest weather.  Every precaution should be taken not to take cold or to chill the surface of the body, as this might bring on an acute trouble of the kidneys.  As soon as the womb has risen out of the pelvis during the fourth month, the corset should be absolutely abandoned, since pressure upon the enlarging womb tends to cause acute Bright’s disease and uraemia, and these troubles are always to be guarded against.  During the later months of pregnancy, when the abdominal enlargement is great, a linen or elastic bandage may be worn with great comfort, but it must be so put on as to support and not press upon the womb.