Heart Diseases in Pregnancy
Over 20,000 women die in childbirth each year in the United States, and about 100,000 infants, and more or less permanent injury from parturition is almost general in mothers. The mortality in the trenches during the present great war is 2 per cent.; the mortality of infants during the first year is 14 per cent. Very much of this mortality and invalidism is attributable to lack of skill in the licensed unfit. We commonly deem parturition merely a physiological process, and for that reason the state permits ignorant midwives and quacks to take upon themselves with impunity the responsibility and the risks of delivery.
It is difficult to draw the line between normal and abnormal parturition, but every labor, as women now are in civilized countries, should be regarded as a grave surgical operation, and the indications that must be met in a surgical operation are likely to occur in almost any parturition. The strength of the patient, the condition of the heart, lungs, kidneys, and blood, sepsis and antisepsis, the nature and technic of the various operations that may be required, and the complications that may arise, are all to be understood and met conscientiously. No physician who has any regard for morality and his own reputation now will accept an obstetrical case unless he has had the woman under frequent observation for months before delivery. If the mother or child dies because of the bungling or surgical uncleanness of the physician or midwife,—and unfortunately such deaths occur almost hourly,—this physician or midwife is guilty of murder. There may be an abnormality of the uterine or abdominal muscles used in parturition, a disproportion between the parturient canal and the child, or various accidents of labor; and these conditions are so frequent in occurrence and so grave that their removal requires great medical skill, fine discernment, quick and exact judgment, and often decidedly courageous purpose.
New methods of treatment frequently appear, and the quack is likely to be among the first by which the new is tried. The use and abuse of pituitrin is an example of such a method. About 1909, pituitary extract as a uterine stimulant was first described and it was immediately taken up by competent men and more frequently, perhaps, by the quack. The extract is from the posterior lobe of the pituitary gland, and when injected subcutaneously or into a muscle it is a very powerful oxytocic. In a few minutes the injection markedly increases the intensity and duration of the pains. The effect lasts for an hour or an hour and a half. Whitridge Williams[129] says a judicious administration of the drug will do away with the use of low forceps in from one-third to one-half of the cases, but its ignorant use places the life of the mother and child in jeopardy. Mundell[130] found twelve cases of rupture of the uterus, thirty-four cases of fetal death, and forty-one cases of fetal asphyxia pallida in which resuscitation was effected only after prolonged and vigorous efforts, sometimes for over an hour.
If there is any serious obstacle at all to delivery in the parturient canal or in the fetal position, or the like, pituitrin is likely to cause rupture of the uterus and asphyxiation of the child. It should never be used when there is the slightest danger of rupture of the uterus; or when the child is suffering; or in a shoulder and most pelvic presentations; or in elderly primiparae with rigid muscles; or when the cervix is not fully dilated, lest the undilated cervix be torn off; or where there is inertia after prolonged effort to overcome an obstacle to delivery. It is never to be used in a normal delivery merely to hasten the birth. Obstetrical cases are tedious, and an impatient physician with an atonic conscience is likely to use pituitrin so that he can get back to his bed.
Comparisons between the fetal mortality after the use of pituitrin or the forceps are erroneous. Quigley[131] contrasted the fetal mortality in these conditions. In 147 pituitrin cases it was 2.7 per cent., in about five or six times the number of forceps cases it varied from 5.7 to 15.63 per cent.; but wherever there is any real need at all for the forceps, pituitrin at once is contraindicated except in easy low forceps deliveries, where in the hands of a skilled man pituitrin may safely replace the forceps to avoid possible instrumental infection of the uterus. There are contractions of the uterus toward the end of gestation, before labor proper sets in, which cause what are called False Pains, and these must not be mistaken for the beginning of labor, as unnecessary examinations and meddlesome interference may bring on great harm. Uterine atony, or weak pains, may affect the patient in the first stage of labor, in which the cervix of the uterus should be dilated; or the second stage, in which the child is delivered; or the third stage, the post-partum period, when the placenta is thrown off. Contractions of the uterine muscle cause pain, and these contractions themselves are called the Pains. In the first stage weak pains may prolong the dilatation of the cervix for days and expose the mother to sepsis or exhaustion, and the child to consequent danger.
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.
Even those obstetricians who induce abortion at any stage of gestation when they deem the woman's life in danger say that heart disease in itself is not an indication for abortion unless there is chronic decompensation with myodegeneration and renal or hepatic insufficiency. Expectancy is the rule. Lusk advises abortion as soon as mitral stenosis is discovered.
Surgeons of the Mayo Clinic, in a report[134] on Operative Risk in Cardiac Disease, hold that a valvular lesion is not a rational basis for judging a cardiopath so far as prognosis in a surgical operation is concerned, but this statement is not true for an obstetrical case. If we except angina pectoris and related diseases, the four disorders of the heart's mechanism that surgeons deem the worst risks in operation are auricular fibrillation, auricular flutter, impaired auriculoventricular conduction, and impaired intraventricular conduction. These conditions are usually accompanied by extensive lesions of the heart muscle.
In auricular fibrillation there are rapid incoördinate contractions, twitchings in individual muscle bundles of the auricular wall. The auricle loses its power to pump the blood and dilates. The pulse is commonly arhythmic and rapid. A permanent fibrillation is worse than a paroxysmal state. The condition is found especially in advanced cases of exophthalmic goitre. In the Mayo Clinic the operative mortality in seventy cases of exophthalmic goitre with auricular fibrillation was only 2.8 per cent.
In auricular flutter, or heart block, there are foci of irritation in the auricular wall which cause rapid coördinate contractions. The auricle may contract twice as often as the ventricle, and the pulse may be regular or markedly irregular. The stimulus for heart contraction normally reaches the ventricle from the auricle by passing along the bridge of primitive tissue which connects the auricle and ventricle. This bridge may be so affected that the stimulus is delayed, or prevented at times from crossing over, or completely blocked. One patient with complete heart block was operated upon at the Mayo Clinic three times in eleven years for appendicitis, cancer of the breast, and the excision of recurring skin nodules, and is still alive and reasonably well. In intraventricular block the risk of operation is worth taking, according to the opinion at the Mayo Clinic, where there is exophthalmic goitre or tonsillitis.
In general, where there is question of surgical operation on a cardiopath, no such operation should be done unless there is definite ground to believe that the operation is essential to improve the heart condition or restore reasonable health. Extremely severe cardiac disease can be relieved or even completely cured by the surgical removal of infectious, mechanical, or toxic sources of heart degeneration, especially goitre. When the myocardial insufficiency is so marked that no medical treatment reëstablishes a reasonable compensation, no surgical operation is permissible. The medical treatment is the only test to learn whether the heart can be put into a condition wherein it will withstand the anesthesia and the operation. Life depends on ventricular action, not on auricular, and the ventricular reserve is the standard for judgment in these cases.
Fibrillation and heart block are grave conditions when found in pregnancy, but disease of the mitral valve because of frequency is more important, and when compensation is unstable mitral lesions are dangerous. In mitral stenosis the enlarged uterus in the last months of gestation, by crowding the intestines and diaphragm, embarrasses the heart. As the diaphragm cannot descend well, the flow of blood out of the right ventricle is not aided by respiration as in normal conditions. Pressure on the abdominal veins increases the blood tension and throws greater work on the left ventricle. In the expulsive stage of labor there is danger of the right ventricle giving way under the added strain.
In mitral regurgitation the left ventricle is dilated, and in pregnancy the regurgitation is increased by the peripheral resistance or obstruction. If the dilated ventricle is also hypertrophied it stands the strain much better. In the second stage of labor the danger is the same as in mitral stenosis. In disease of the aortic valve the strain of child-bearing is on the left ventricle, but patients in this condition undergo labor more successfully than do those with mitral disease.
Labor in any cardiac disease requires close watching even when the compensation is good. There is always a possibility of collapse in the third stage or during the puerperium. The obstetrician must stay by the bedside, and he is to have everything ready for a sudden emergency, which is likely to result in death if not instantly met. All the instruments for operative delivery are to be kept sterilized and ready for immediate use. When symptoms of imminent collapse appear, delivery is to be done at once. If a cardiopath collapses in the early stages of gestation, before the child is viable, the rule explained in the chapter on Abortion holds—the child may not be killed by removal to save the woman's life.
Jaschke,[135] in his consideration of 1548 pregnant cardiopaths, found that seven-eighths went to term, and that the women were prematurely delivered in only about 9 per cent. of the total number of cases. Therapeutic interruption of pregnancy was necessary in only about 1 per cent. The high mortality reported by many good obstetricians is a proof that the treatment of cardiac conditions requires an experience in clinical medicine and a skill lacking, as a rule, in specialists who are not internists.
A combined mitral and aortic disease with great enlargement of the heart, heaving of the chest wall, and some protrusion makes pregnancy very dangerous. Osler thinks mitral insufficiency in itself not very dangerous. He had one patient with such a condition, a loud apex systolic murmur, and some enlargement, who bore nine children and lived to past sixty years of age. Mitral stenosis is not so favorable, but even in extreme stenosis some women bear several children without collapse.