Accuracy of Change in Maternal Serum Alfa Fetoprotein as a Diagnostic Test for Quantitative Assessment of Feto-Maternal Hemorrhage

Abstract

etomaternal hemorrhage is considered to be a grave complication which may occur during pregnancy(Sebring et al., 1990). Fetal and maternal circulations normally are supposed not to be in direct contact (Bernstein et al., 1992). In normal pregnancy this abnormal contact between the fetal and maternal circulations may occur so late during delivery. Up to 1 ml of blood may pass. But in an abnormal pregnancy, fetomaternal haemorrhage is defined as the haemorrhage of 30 ml or more, of whole blood from a fetus into the maternal circulation. As less than 30 ml is considered benign and passes without any remarkable side effects (Sebring et al., 1990). The problem in fetomaternal hemorrhage appears when fetal blood escapes into the maternal circulation in a considerable amount 30 ml or more. That shall compromise the fetal condition leading to many morbidities and mortalities. The result varies from minimal degree of fetal anaemia up to severe degree of fetal anemia. And lethal hydrops fetalis may follow that, leading to fetal cerebral edema, kernicterus, fluid collection in all body spaces, severe pallor and failed circulation (due to the escaping red cells) and eventually ending in death of the fetus (Zizka et al., 2001). Quantification of fetomaternal haemorrhage is done when severe FMH is suspected, and accordingly dose of Ante D can be adjusted if Rh –ve mother gives birth to Rh +ve baby. Additional dose of 10 lg of antiD should be given for every additional 0.5 mL of fetal RBCs in maternal circulation(White et al., 2009). Methods for quantification of FMH: Kleihauer–Betke test is the gold standard test for quantification of FMH (Maciuleviciene et al., 2008). The controversy appears in that Kleihaeur -Betke test is a test which requires a specific laboratory setting and a highly performing haematology specialist so it is not that easy to be conducted and to give reliable results and is also liable for inter and intra-observer variations as it is subjected to the human error (in the microscopic manual method)(Agarwal et al., 2011). Also the time between sampling and testing, if prolonged, this may lead to clotting of the sample and consequently false interpretation (in both of the microscopic manual and the microscopic automated methods)(Lachman et al., 1977). Moreover, over estimation for the number of fetal erythrocytes may occur by KBT, as Freese and Titel (1963)reported 10–55% women with fetal erythrocytes in their blood in the first trimester as a result of the increased amount of HbF in maternal circulation. Another reason could be the staining of adult reticulocytes as described by Clayton et al. (1963) where all the 50 (100%) of antepartum and postpartum women and 60% of controls (males and non-pregnant females) were positive for fetal erythrocytes. Alpha- fetoprotein(AFP) is found in both fetal serum and also amniotic fluid. This protein is produced early in gestation by the fetal yolk sac and then later in the liver and gastrointestinal tract. The true function of AFP is unknown(Johnson et al., 2012). Since maternal serum level of Alpha-Fetoprotein is found by evidence to be raised in cases of severe fetal anaemia (Bartha et al., 2003). Also based on assumption that damaged trophoblasts would allow both AFP and fetal cells to escape into maternal circulation. Therefore changes in level of maternal serum Alfa-Feto protein can be used for detection of significant FMH. The advantage of measuring AFP over KBT during FMH would include that AFP is dispersed within maternal