Any of the acute infections, as typhoid, typhus, smallpox, measles, scarlatina, and the others, attacks a pregnant woman as readily as one who is not pregnant. Pregnancy, as a rule, lessens the resistance to the infection, and the infection is likely to cause abortion. The toxin of the infection is added to the physiological toxins of pregnancy, the kidneys often are overwhelmed, and there is a tendency to hemorrhage. After the exhaustion from the disease, delivery, whether premature or at term, is liable to end in collapse, especially if the heart or lungs have been injured. Puerperal sepsis, either general or local, is a common effect of these bacterial diseases. In smallpox there is infection from the pustules and the virus itself; in typhoid the typhoid bacillus and the streptococci in Peyer's patches get into the blood; in influenza, pneumonia, erysipelas, and diphtheria the bacteria directly cause sepsis, and in scarlatina the pus organisms from the throat are found in the septic foci.
In these infections the fetus may be killed by the high temperature; it may die from asphyxia brought on by feeble maternal blood-pressure and consequent stagnation of the circulation in the uterine sinuses; it may be overwhelmed by maternal hemorrhage; by deoxidation of the maternal blood, as in pneumonia; by a hemorrhage in the placenta, and a consequent separation of the placenta itself from the uterine wall; by fatty degeneration of the fetal villi, which renders respiration of gases impossible. Again, the child may be infected by the disease of the mother, or it may be killed by the toxins in the maternal circulation.
The communication between the fetal and the maternal blood systems is as indirect as that between the air in a man's lungs and his blood. The communication between mother and fetus is by osmosis, but certain toxins, drugs, and bacteria may also pass from the maternal to the fetal circulation through the placenta. Strychnia injected directly into the embryos of animals by Savory and Gussarow killed the mother after passing to her through the placenta. There is no direct communication (except by osmosis) between the fetal chorionic villi and the maternal intervillous blood spaces. In the first half of pregnancy fetal and maternal blood are separated by the syncytium, Langhan's layer of cells, the stroma of the villi, and the walls of the fetal capillaries; in the second half of gestation Langhan's layer gradually disappears. In the fetal blood-vessels are found many nucleated red corpuscles, but these are lacking in the maternal intervillous spaces. Sänger also discovered that in pernicious leucemia the leucocytes of the mother are not present in the fetal circulation.
That gaseous substances pass through the fetal barrier of tissues was proved by Zweifel, Cohnstein, and Zuntz. Zweifel showed that chloroform administered to the mother rapidly reaches the fetus. As early as 1817, Mayer proved the passage of cyanide of potassium. Since then we have been made certain of the transmission of iodide and ferrocyanide of potassium, salicylic acid, bichloride of mercury, methylene blue, and many other substances. Krönig and Futh, in 1901, determined that the maternal and the fetal blood freeze at the same temperature, which indicates that they possess equal osmotic power, and that osmosis may occur in either direction.
Some bacteria do not get through to the fetus, but a few do get in. Tubercle bacilli were found in the fetus by Birch-Hirschfeld[139] in 1891, and Schmorl[140] demonstrated them in 50 per cent. of the placentas in one series of examinations. Bar and Renon[141] found them in the blood of the umbilical cord in two of five cases. Actual congenital tuberculosis is possible, though very exceptional: the bacteria either pass through the wall between mother and fetus, or destroy this wall and then get in. Smallpox, measles, and scarlatina, the causes of which have not yet been demonstrated; typhoid, cholera Asiatica, pneumonia, bubonic plague, erysipelas, pus infection, anthrax, syphilis, febris recurrens, and malaria have already been demonstrated in the fetus. Lynch of Johns Hopkins collected sixteen cases of typhoid in the fetus. I found the typhoid bacillus in the liver and kidneys of a still-born fetus whose mother was ill with typhoid fever; this case was not among those collected by Lynch.
The majority of writers give unfavorable prognoses for typhoid in pregnancy. Abortion or premature labor is extremely common, with great danger to the mother's life. When labor begins in these cases the last sacraments should be administered early. Therapeutic abortion in typhoid is very likely to cause death, yet a number of women recover after abortion. As regards the woman's life, cases of premature labor have a worse prognosis than early abortion. The greatest danger is while the fever is high, and abortion is commoner in the first week of fever than in the second or third. In protracted typhoid abortion is likely to occur in the fourth week or later. After defervescence the prognosis is better, but there is always danger. Different physicians have markedly varying results. There is no medical condition where skill in the physician counts more than in typhoid; it is the supreme test of the therapeutist. Sacquin[142] collected from various sources the statistics of 233 cases of pregnancy during typhoid, and abortion or premature labor occurred in 150 of these, with death in 16 per cent. Many skilful men have a mortality as low as 3 per cent. in typhoid not complicated with pregnancy.
The subject of typhoid is too vast for complete treatment here: the article on Typhoid in the American edition of Nothnagel's Encyclopedia of Practical Medicine covers 472 large octavo pages. A very important point is not to mistake typhoid for a septicemia in its early stage. A Widal reaction should be made in apparently septic cases to exclude typhoid. Sometimes, however, a streptococcic infection will give a positive Widal, and there may be a mixed typhoid and streptococcic infection.
Smallpox in pregnancy causes abortion or premature labor in the majority of cases, and the child usually dies. The child may be born in the eruptive stage, or pockmarked. Franklin reported a case where a vaccinated woman was delivered of a child while her husband was in the house ill with smallpox. The mother did not take the infection, but the child was born dead of smallpox: the contagion had passed to the child through the unaffected mother. Vaccinated women at times bear children which are after birth immune to vaccinia and smallpox—vaccinia, in the commonly held opinion at present, is an attenuated smallpox. Pregnant women should be vaccinated, when there is smallpox in their neighborhood, to protect themselves and their children, unless they have been successfully vaccinated within four or five years.
Vaccination prevents smallpox in more than 90 per cent. of the exposures to the disease. The death-rate was 58 per cent. in the unvaccinated cases and 16 per cent. in the vaccinated in a group of 5000 cases of smallpox studied by Welch in 1894. During the eighteenth century, according to Bernouilli's calculation, one-twelfth of all the children born succumbed to this disease. In 1707, in Iceland, 18,000 of the entire population of 50,000 died of smallpox. As late as 1885, 3164 persons died of the disease in Montreal in one epidemic brought on at a time when vaccination had been neglected. In Prussia, from 1851 to 1860, without compulsory vaccination for civilians, there were 36,577 deaths from smallpox; in the Prussian army during the same time, with compulsory vaccination, there were only fourteen deaths. During the war of 1870 the French armies, without vaccination, lost 23,469 men from smallpox; the German armies lost only 459 men and there was a great epidemic of the disease in Germany at the time.
The efficiency and necessity of vaccination against smallpox, which is as virulent now as it ever was, is so certainly established that a parent or guardian who neglects or refuses to have children vaccinated when exposed to the disease is guilty of homicide through neglect if an unvaccinated child under his care dies of smallpox. Revaccination is necessary every eighth year if smallpox reappears. Agitation against vaccination is not mere ignorance: it is a dangerous crime, exactly like loosing a mad dog; and it is combined with the insolence of ignorance. Persons who have seen smallpox are very much afraid of it, because it is one of the most dreadful afflictions humanity is exposed to; those who have not seen it, yet say they are not afraid of it, are mere fools.