[131] _Jour. Amer. Med. Assoc._, April 10, 1915.
In the second stage the abdominal muscles, which push the child out of the uterus, fail to work if the pains are weak. Causes of unsuccessful pains in the second stage are: an infantile uterus, fibroids or other tumors in or near the uterus, peritoneal adhesions, a full rectum or bladder, abnormal position of the uterus, a pendulous abdomen, diseases of the uterine wall, scars from past operations, chronic metritis or endometritis, primiparity in relatively advanced age, twins, distention of the bag of waters, gas in the uterus, abnormal position of the child, contracted pelvis, adhesions of the membranes about the os uteri, fatigue of the woman, and tetany or stricture of the uterus. The obstetrician must be able to diagnose the special cause and treat the indications.
One of the causes of weak pains is a diseased heart. Systolic murmurs at the base of the heart and an accentuated second aortic sound are quite common in pregnancy and may not be of grave importance. If there is a genuine cardiac lesion with good compensation, the labor is usually successful and without notable damage to the woman, although obstetricians like De Lee think that such patients appear to develop decompensation sooner than do women who are not pregnant. If the heart disease is advanced and the heart is in unstable equilibrium, especially if there is myocarditis or fatty degeneration, the heart is likely to break down in pregnancy or labor. In chronic cardiac lesions, pregnancy, through venous congestion, tends to renal and hepatic disturbance, or to dyspnoea and carbonic acid narcosis. The uplifting of the diaphragm by the enlarged uterus increases the respiratory difficulty. There may be edema of the lungs, hypostatic pneumonia, dropsy, insomnia, albuminuria, and other serious symptoms.
During labor a diseased heart may fail and cause sudden death, especially if the second stage is prolonged. At times there is collapse and death shortly after delivery. The mortality of heart disease in pregnancy varies in the reports on various series from 4 to 85 per cent. Babcock[132] says that the mortality in mitral disease in pregnancy is 50 per cent.; that in disease of the aortic valve is 23 per cent. These figures are far above those given by later obstetricians of skill. Fellner and Demelin, in ninety-four and forty-one cases respectively, had a mortality of only 6.3 and 5 per cent. Hirst says he never lost a case. Jaschke[133] found a mortality of only 4 per cent. in 1548 cases of pregnant cardiopaths. A great danger is in treating heart conditions by general rules, and in giving digitalis and other drugs without discrimination. In uncompensated heart conditions many of the children die from prematurity, abruptio placentae, diseases of the placenta, or asphyxiation.