=The valves of the heart= are not uncommonly found to be diseased in pregnancy, the mitral being the most often affected, either as an insufficiency or as a stenosis (a narrowing of the mitral opening). Mitral stenosis is the most serious of all heart complications of pregnancy, and where this is present, a woman should be advised to avoid conception. In other mitral lesions, many pregnancies may be successfully passed, if compensation is maintained; but every one brings further damage to the already weakened heart, and reduces its reserve of force. If the heart breaks down early in pregnancy, and does not respond to medication, abortion should be induced. In the second half of pregnancy, the mother should be given the prior chance, but the child should be saved, if possible. =Renal diseases=, such as nephritis, may not only induce abortion by destroying the fœtus, but the kidney lesion may be greatly aggravated by the pregnancy. The most careful observation of the patient’s condition, the regular examination of the urine, and the scientific management of the diet is necessary to relieve the work on the kidneys and keep the patient in a moderate degree of health. It is the duty of the nurse to protect her patient against fatigue and chill, and to see that the proper diet is followed; but other symptoms, such as headache and disturbance of vision and developing edema, must be noted and reported to the physician at once. =Diseases of Liver.=—Acute yellow atrophy is a rare condition, which, for reasons unknown, is promoted by pregnancy. _The symptoms_ are intense headache and pain in the abdomen, possibly accompanied by vomiting and purging, which are soon followed by coma. There is generally a certain amount of jaundice. The urine is diminished in amount and contains albumin, casts, and sometimes blood. There is no known treatment, and the end is death. =Diabetes= is seldom found associated with pregnancy. Its presence is unfavorable to conception and to gestation. Mother and child are both less secure. Abortion or premature labor is the rule. =The hæmorrhages= of pregnancy in the first half generally mean abortion, and in the last half, either placenta prævia or premature detachment of the normally implanted placenta (see p. 228). =Abortion= is the expulsion of the ovum before the fœtus is viable, that is, before it is capable of maintaining life after birth. This means the twenty-eighth week, or the seventh month. Subsequent to the seventh month, the interruption is called premature labor. Abortion is a miniature labor, consisting of a stage of dilatation, a stage of expulsion, and a stage of involution. The interruption of the pregnancy may occur spontaneously or be induced. In spontaneous cases the causes may be sought in diseases of the ovum, or in the mother, in injuries to the uterus or its contents, and such systemic affections as syphilis, Bright’s disease, alcoholism, lead poisoning, etc.