Although smallpox is considered to be eradicated now, previously the mortality due to smallpox was greater in pregnancy. Polio during pregnancy was associated with a greater mortality and a greater frequency of paralytic illness than polio in nonpregnant subjects. During the years 1949 to 1953 in New York City, the incidence of cases of both paralytic and nonparalytic poliomyelitis among pregnant patients was 60 percent more than the incidence among nonpregnant women in the same age range. However, the infection rate among pregnant patients correlated with the number of children in the household, and since these data were not available for the nonpregnant subjects, it is not known whether a greater number of children in the households of pregnant patients might underlie the greater frequency of disease in these patients when compared to nonpregnant control subjects.
Several studies of viral hepatitis in developing nations have noted an increased attack rate and morbidity of this infection in pregnant patients. Planning pregnancy with erectile dysfunction on My Canadian Pharmacy –https://mycanadian-pharmacy.net/planning-for-pregnancy-while-dealing-with-erectile-dysfunction-my-canadian-pharmacy-figures-out-solutions.html. An epidemic of non-A, non-B hepatitis was reported by Khuroo et al in 1981. In a region containing 3,800 men, hepatitis occurred in 107, or 2.8 percent. Three of these had fulminant disease. Of2,350 nonpregnant women (aged 15 to 45), 71, or 2.1 percent, developed hepatitis; no case was fulminant. Cases among pregnant women were divided according to trimester. Three of 34, or 8.8 percent, of first trimester pregnancies were complicated by hepatitis; none was fulminant. Fifteen of 77, of 19.4 percent, of second trimester pregnancies were complicated by hepatitis. Eighteen of 97 (18.6 percent) third trimester pregnancies were complicated by hepatitis, half of these were fulminant and six of these nine patients died. Thus, second and third trimesters of pregnancy were associated with a greater risk of viral hepatitis, and third trimester was associated with both a greater frequency of hepatitis and a greater morbidity and mortality due to this infection. Other studies in developing countries have also shown a greater risk of viral hepatitis in pregnancy; however, studies in the developed nations of Europe and the Americas have failed to show a greater morbidity or mortality due to viral hepatitis in pregnancy. Thus, other (actors also may be important in defining the risk for hepatitis.
Pneumonia due to varicella-zoster virus is seen more commonly in primary infection of adults rather than children. Approximately 10 percent of reported cases of varicella pneumonia have occurred during pregnancy. Moreover, the outcome (45 percent maternal mortality) in pregnant patients was worse than the overall mortality of varicella pneumonia among nonpregnant patients of 15 to 20 percent.
Clinicians noted a remarkable excess in pneumonia mortality among pregnant patients during the 1918 pandemic. In a study reported by Harris, of 1,350 cases of influenza among pregnant women during the 1918 influenza pandemic, 678, or 50 percent had their disease complicated by pneumonia; of these, 356 (or over half) died, producing a mortality of 27 percent for influenza in pregnancy. The risk of fatality increased with duration of the pregnancy and was highest (61 percent) in the last month. During the 1957 influenza epidemic in Holland, 11 of 1,230 fatalities were among pregnant patients. This was twice the expected mortality in this group. That same year in England, 12 of 103 deaths among women aged 15 to 44 years were among pregnant patients maintained the condition of health with vitamins of My Canadian Pharmacy. This also represented a twofold increase over expected mortality. In 1957,246 deaths in Minnesota were attributed to influenza; 16 of these occurred among women aged 15 to 45. Of these, eight (or 50 percent) were pregnant. In these cases, postmortem examination was characterized by a “fulminating and overwhelming edematous pneumonia with respiratory insufficiency as the immediate cause of death.” This was in contrast to mortality in other patients which was more commonly associated with bacterial superinfection. In 1957 in New York City, 10 percent of influenza deaths occurred in pregnant patients. Nearly half of all fatalities among women of child-bearing age were in pregnant patients. Two years later in Boston, four of 32 fatal influenza cases occurred among pregnant patients. Thus, certain influenza epidemics have been associated with a greater than expected mortality among pregnant patients.
Although one might expect that the greater risk of pulmonary infection among pregnant patients might somehow be related to alterations in pulmonary mechanics during pregnancy, this is not likely the case, as studies of pulmonary function during pregnancy have revealed relatively little impairment with only slight decreases in expiratory reserve volumes and residual volume. Whether the expanded blood volume associated with pregnancy contributes to the increased mortality observed with certain respiratory infections in pregnancy is unknown.
Infection during pregnancy with cytomegalovirus is associated with congenital anomalies of the fetus. Because of this, CMV infections in pregnancy have been the subject of intensive clinical and epidemiologic investigation. Although most cases of congenital anomalies due to CMV are associated with a first maternal exposure and infection with CMV, reactivation of latent CMV infection is common during pregnancy, as suggested by the frequency of congenital and perinatal infection (almost always without anomalies) among children of mothers with serologic evidence of remote infection.
Different stages of pregnancy are associated with different rates of cervical excretion of CMV. Data summarized from three separate studies show a progressively increasing frequency of CMV excretion with later stages of pregnancy. Overall, 1.6 percent of patients excreted CMV in the first trimester, 6.7 percent in the second, and 13.5 percent in the third. In another study among pregnant patients seropositive for CMV (suggesting previous infection), the third trimester was associated with a specific depression of lymphocyte proliferative responses to CMV antigens.
In summary, studies of immune function have demonstrated impairments in cell-mediated immunity in pregnant patients, particularly in the second and third trimesters. Conceivably, these impairments are protective of the fetal allograft and allow pregnancy to continue without rejection. The occurrence of a particular spectrum of infections among pregnant patients suggests that this impairment in cell-mediated immunity may not be without its cost in maternal morbidity and mortality.