A Successful Method for Fetal Survival in Rhesus Disease

Introduction Prior to immunoprophylaxis with RhIG, 7-8 percent of Rh negative women with Rh-positive, ABO-compatible infants developed anti-Rh (D) within six months of delivery; while only one percent of Rh-negative mothers delivering ABO-incompatible babies were immunized. A significant number of women in Iran become sensitized because immunoprophylaxis is not widely practiced, resulting in hemolytic diseases of the newborn. Methods In this paper, the small-volume (500-600 cc) plasma exchange method was investigated in treatment of 32 women with Rhesus disease. Over period of 4-16 years, these sensitized women had 157 unsuccessful pregnancies. Small-volume plasma exchange was carried out weekly from the end of their first trimester throughout their pregnancy to reduce anti-D titer. Results 31 out of 32 mothers delivered babies successfully. Conclusions Small-volume plasma exchange procedure is an easy and safe method, both for the mother and the fetus and it can produce brilliant results in treatment of Rh disease. This method is inexpensive and practical, even in small blood transfusion centers. Introduction Fetal erythroblastosis was recognized as early as 400 BC and its pathophysiology was described in 1940.1,5 Infusion of Rho (D) Immunoglobulin as prophylaxis has reduced the disease rate1,2,4,8,15,17,20 from 10-17% to 0.1%.1,3 Despite all efforts, however, fetal erythroblastosis has not been eradicated entirely.3,4,22 According to some reports, the mortality rates of fetuses and infants of hyper sensitized mothers prior to application of proper treatment was 30% to 93%.3,5 With new, diverse and developed treatments, the fetal mortality rate has been greatly decreased. The chance of rescue for infants of severely Rh-incompatible mothers in some centers has risen from 33% to 78.2%,6,7 and even in some reports to 94% and 100%.3,7,8,9,12 Intrauterine Intravenous Transfusion (IUIVT),31,32 Intraperitoneal Transfusion (IPT)30 or Intravenous Immunoglobulin injection (IVIG)33 have been the methods used in treatment of sensitized women. IUIVT requires advanced equipment and fetal mortality rate in each attempt is 1-9%, even if performed by the most experienced staff.14-16,26 IUIVT therapy is practically restricted to a few advanced medical centers in the world and has never been fully used in Iran. The use of IPI or IUT therapy may result in 20% fetal mortality.3 IPT and IUIVT have been of no use for highly sensitized cases that get hydrops or fetal mortality before the 26th week. In these cases, it is recommended that either plasma exchange(10-11 liters) should be performed, or high dose immunoglobulin should be injected intravenously until the time is appropriate for blood transfusion into the fetus umbilical cord vein or peritoneal cavity.3,17,18,29,34,35 High volume plasma exchange has not been used frequently in the treatment of Rh disease due to its common complications (citrate toxicity, cholinesterase deficiency and problems with the replacement fluids)26 and its despairing outcomes. Although the removal of several liters of plasma per week will result in transient reduction in the anti-D titer during or immediately after treatment, a chronic, significant reduction in antibody titer is difficult to achieve by this technique. Furthermore an increase in anti-D titers has been observed soon after plasma exchange was stopped.39 This rebound phenomenon has been attributed to the removal of the negative feedback influence on further anti-D production by high circulating titers of anti-D antibody. High-volume plasma exchange has been regarded as costly, time consuming, and producing unreliable results.5,6,11,24 Unfortunately the problems associated with high-volume plasma exchange have overshadowed the beneficial outcomes of small-volume plasma exchange,7,22,23,27 inasmuch as