The "Rh factor" — incompatibility of blood—accounts for many childless marriages
ROBERT H. FELDT, M.D.
THE happy young couple were the picture of good health as they stood before the altar. They had been childhood sweethearts, their interests, tastes
and religions were the same. Their friends agreed this would be a perfect match. How could anyone suspect that his blood and hers were constitutional enemies? Because of this incompatibility of blood their first baby died of anaemia three days after birth, the second was stillborn and the third pregnancy ended in a miscarriage. At that time their doctor could find no explanation for the tragedies.
But this happened before 1940. when the Rh factor
of blood was discovered. Since then research has proceeded so rapidly that nearly all the pieces of this marital puzzle have been fitted together. Now the hazard that confronts about 13% of betrothed couples can be recognized by a simple blood test which will tell in advance if the marriage is eugenically unwise.
The conservative Journal of the American Medical Association says that “rarely has a medical discovery been so quickly or widely accepted” as has the Rh factor. But the discovery came too late to help this young couple. The young husband’s blood had the Rh factor. He was born with it, always would have it, and had they lived his children would have had it too. The wife’s blood was normal in every way, but it lacked this Rh factor and, therefore, was a natural antagonist of Rh blood. The blood of their unborn babies was slowly destroyed by their mother’s blood in a battle against the Rh factor they inherited from their father.
Knowledge of the Rh factor not only explains many of the disasters of pregnancy but it accounts for some of the baffling reactions to blood transfusion. Now doctors know how to prevent sudden death when a seriously ill patient is given a donor’s blood. In paternity suits the Rh factor will become a strong legal link in the chain of evidence.
Famed blood researchers, Karl Landsteiner and Alexander S. Wiener, of the Rockefeller Institute, modestly announced their epochal discovery in an obscure scientific journal. They first regarded the Rh factor as simply another means of identifying or typing human blood. In their experiments red blood cells of rhesus monkeys were repeatedly injected into a rabbit. To the defense system of any animal—rabbit or human—blood cells from another type of animal are foreign invaders, to be repelled as Vigorously as if t hey were disease germs.
Eventually the rabbit’s defensive forces manufactured blood antibodies for the specific purpose of destroying monkey red blood cells. The rabbit finally became immune to monkey cells in the same way that human beingsdevelop antibodies againstdiphtheriaand become immune to the disease following vaccination with diphtheria toxin. When the almostcolorless blood serum of the immunized rabbit was mixed with monkey blood on a glass slide, the destructive process could be studied under a microscope.
Destroys Human Cells
fl^HE scientific curiosity of Landsteiner and Wiener A led them to further experiments. One of them mixed a drop of his own blood with the rabbit’s blood serum and sat down to his microscope to see what would happen. He watched with amazement as these human blood cells underwent the same destruction as the monkey cells. But human blood had never been injected into the rabbit. Why should the rabbit’s serum show an immune reaction to man’s blood? Immediately a drop of blood from another laboratory worker and another were tested, and the cells perished in the same way.
The rabbit’s antibodies destroyed the red blood cells of 85% of the people tested. Landsteiner and Wiener concluded that red blood cells from the majority of human beings had a property or factor very much akin to some element in rhesus monkey cells. The relationship was so close that rabbit blood immune to rhesus monkey red cells also attacked these human cells. In honor of the little rhesus monkey they named their discovery the Rh factor.
Since 1940, hematologists have tested thousands of persons in New York, London, Montreal, Melbourne and many other places. The results have all been similar: about 85% of the white population have this factor—they are Rh positive. The remaining 15% do not have the factor and are said to be Rh negative. There also appear to be racial differences. Ninetynine per cent of Chinese tested have the Rh factor. Among South American dark races about 95% are positive.
Doctors rushed into Rh research in the hope that it would explain distressing and sometimes fatal blood transfusion reactions. Following childbirth a New Jersey woman suffered a severe reaction when she was given blood from her husband. Subsequent tests showed that she lacked the Rh factor and her husband was Rh positive. Incidentally she had a history of three miscarriages and seven stillbirths. 1 ests of other women with similar histories showed that they, too, were Rh negative, while their husbands were Rh positive.
Evidence like this multiplied many times has revealed the Rh factor as a major cause of childless marriages. Thirteen per cent of marriages are in the zone where the husband’s blood has the factor and the wife’s does not.
Normally during pregnancy the blood of an infant and its mother do not mix, but mishaps sometimes occur. A minor injury to the placenta—the attachment between mother and baby—or a clot or strain in this vital spot may permit mixing of blood. Ordinarily such an accident means nothing, but if the father is Rh positive the chances are that the child will inherit his Rh factor. Then if the mother is Rh negative the deadly process of all destruction begins.
There is no mother love, no reasoning, in the mother’s system of defense because its function is to battle and destroy any foreign element. The reaction to the Rh factor of the infant’s red cells is as ruthless as it would be against the most virulent toxin or disease germ. Like the rabbit of Landsteiner and Wiener, the mother develops antibodies which will seek out and annihilate cells with the Rh factor wherever they are. As the immunization process unfolds, the mother s antibodies filter through the placenta and attack the baby’s red blood cells. They are liqueified and destroyed almost as fast as the infant’s tissues can make them.
If the mother’s antibodies are powerful and concentrated, the child may be stillborn. So many of its
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vital red blood cells will be destroyed that life is impossible. A miscarriage or stillbirth results. If the baby does survive its alloted period, it may be born with a dangerous blood disease called erythroblastosis fetalis.
Three fourths of babies with erythroblastosis fetalis are born dead or die within the first week. Some have an incurable jaundice. There are milder forms in which anaemia is the only abnormality and some of these children recover. Doctors now suspect that some cases of unexplained mental deficiency in later life are due to this disease of the newborn.
An Rh negative mother and an Rh positive father may have one perfectly healthy baby, then a series of mishaps. This is because the first pregnancy did not cause the formation of sufficient antibodies. It may take further pregnancies, with increased exposure to the Rh factor, to build up the mother’s immunity to a point where it would be harmful to the baby. Specialists at Montreal’s Royal Victoria Hospital report that in their experience it is not at all unusual for such parents to have one or two and sometimes three normal children before the inevitable pregnancy pattern develops.
Other authorities are sure that even the first pregnancy is extremely hazardous. In a large London hospital one seventh of all Rh negative mothers pregnant for the first time suffered miscarriages, stillbirths, or bore
babies with severe anaemia. One
thing is certain, a mother who has once given birth to a child with erythroblastosis fetalis stands less than a 5% chance of having a normal baby by the same husband.
Danger to 13%
If at least 13% of all marriages are potentially dangerous, why aren’t there more infant fatalities? There are several known reasons and probably as many unknown elements at work to account for this discrepancy. In the first place the attachment between mother and child—the placenta must be injured to permit the mixing of blood and this is not a common occurrence.
Secondly, the modern tendency to restrict the size of families to one or two children has a limiting effect on the number of cases, because of the slowness of some mothers to develop full immunity against the Rh factor. There would be many more children with the disease if every Rh positive father passed on the factor to all his offspring. Happily there are a good many men with the factor who are so constituted hereditarily that only half their children inherit the factor. The babies who do not inherit it will develop normally.
The list of babies with erythroblastosis fetalis would undoubtedly be longer if the many mild and unrecognized cases were included. We will hear of it more and more now that doctors know how to make the diagnosis. In pre-Rh days many cases were wrongly classified.
Not only does the Rh factor explain the cause of anaemia of the newborn, but it suggests a plan of treatment that gives great promise. In the old days when such a child was born it was recognized that a blood transfusion offered the only hope—faint though it was. In casting about for likely donors, doctors often selected the father.
In the light of modern Rh knowledge, the next to the most deadly thing that could be done for the child was to give him a transfusion of his father’s blood.
For several days after birth the infant’s blood would contain heavy concentrations of antibodies it had absorbed from its mother. These would attack and destroy the father’s Rh positive blood cells as quickly as they entered the baby’s veins. At best, this process added a burden to the struggling circulation of the child. At worst, it caused a transfusion reaction and resulted in death.
If the father was not available for transfusion, the mother’s blood was sometimes used and this was the most deadly method of treatment. The injection of mother’s blood, loaded with antibodies, often brought about destruction of the few red cells that remained to the infant and death quickly followed. For the same reason harmful reactions sometimes resulted from breast feeding because the mother’s milk also contained antibodies.
Safe Blood Transfusions
In St. Louis a baby was born with erythroblastosis fetalis in 1941. He was given three small transfusions of his mother’s blood and his condition became worse after each one. Then his doctor received the latest medical journal that told about a similar case. A professional donor was found whose blood was Rh negative. Transfusions of the donor’s blood cured the sick child in a few days.
Harmful reactions to blood transfusions are now past history in the treatment of erythroblastosis fetalis. Doctors know that the only blood to use is that from an Rh negative donor whose red cells will not be destroyed by the antibodies lurking in the infant’s blood stream. If the baby’s life can be prolonged for a week or two, the antibodies will disappear from his blood and his own red cells will be safe from further attack. New blood cells will be manufactured by the child’s tissues and permanent recovery usually follows.
Most large hospitals keep a list of Rh negative donors and with this blood
many lives are being saved. In some cases the babies get well 24 hours after the proper transfusion. A group of London doctors have cured 95% of babies with transfusions of Rh negative blood. In the same hospital, when only hit-or-miss methods were known, only a small proportion were saved by transfusion.
Many obstetricians recommend the prenatal testing of every pregnant woman. If she is Rh negative they prepare to give the newborn baby an immediate transfusion of Rh negative blood.
If young couples really want to be sensible about marriage they can scarcely ignore the Rh factor. The prospective bride’s blood should be tested first. If she has the Rh factor, and the chances are 85 out of 100 that she will have it, there is nothing more to worry about. If she lacks the Rh factor the man should be tested, and if he is also negative there is no cause for alarm; but if his blood is Rh positive, danger lies ahead.
If this occurs, the young couple, with the help of their family doctor, will have to decide which of several courses to choose. The Rh factor cannot be changed. The couple can give up the match or go ahead and marry with full knowledge of the Rh gamble.
If they marry they may decide to remain childless or adopt a baby, or, what’s most frequently done, they may plan to have one or two children of their own, knowing that there is a greater chance for the first or second child to escape the disease. As the end of pregnancy approaches they will want an Rh negative blood donor standing by. They should understand that with each subsequent pregnancy the odds favoring erythroblastosis fetalis mount higher and higher.
As research advances, a way may be found to remove the vicious antibodies from the mother’s blood before they can harm the baby.^ But at best this is still a faint hope for the distant future.
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