=Accidental hæmorrhage= may be the result of an injury or a blow, but in many cases, there is no such history. The hæmorrhage is most frequent in the later months of pregnancy, and may be without any apparent cause. The hæmorrhage may be entirely inside the uterus (concealed hæmorrhage) or it may appear externally. The hæmorrhage, when concealed, takes place back of the placenta or between the membranes and the uterine wall. If the hæmorrhage is concealed, it is usually followed by an attempt to expel the child. If the hæmorrhage is pronounced, systems of shock appear. _The diagnosis_ is made by the symptoms which are summarized in differentiating this condition from placenta prævia (p. 231). From this affection, nearly all the children and half the mothers die. [Illustration: Fig. 99.—Various forms of placenta prævia compared with normal attachment of the placenta. (American Text Book—Williams.)] When the hæmorrhage is external and slight, the _treatment_ may possibly be expectant for twelve hours, if carefully watched, but usually the symptoms become so serious that immediate emptying of the uterus is required either by the Vorhees bag, digital dilatation, version and extraction, or Cæsarean section, the method chosen being dependent upon the amount of the hæmorrhage, the vigor of the mother and the condition of the cervix, os, pelvis, and child. =Placenta prævia= is the name given to a placenta that is attached low down in the uterus so that its margin or a large part of its mass overlies the os. This happens through the action of the egg which embeds itself too far down on the endometrium—too close to the cervix. Three different kinds are known and named from their manner of encroaching on the os, as marginal, partial, or central implantation of the placenta. The hæmorrhage is from a loosening of the placental attachment owing to the stretching and growth of the uterus. _There is only one symptom of placenta prævia—sudden, painless, causeless hæmorrhage._ The bleeding seldom appears before the twenty-eighth week, and no suspicion of a placenta prævia may arise before the appearance of hæmorrhage, which, as a rule, _is soon repeated_. Labor frequently comes on prematurely and malpresentations naturally result from the inability of the presenting part to fit itself into the pelvis. There is no bag of waters, hence the first stage is longer and bloodier and fraught with much danger. Interference is regularly indicated to save the life of the mother, while the child also has a high mortality. Puerperal infection is not uncommon. Placenta prævia is always an emergency. If the patient can be kept under observation in a good hospital, one may temporize, but under other conditions the uterus must be emptied at once, even if only a single hæmorrhage has developed. The indications are, (a) to control the bleeding, and (b) to empty the uterus. The life of the child must be disregarded and the mother alone considered.