Fetal hemoglobin in women with normal and with hydatidiform molar pregnancy

Abstract

The quantity and the rate of synthesis of fetal hemoglobin (HbF); the level of HbF-containing erythrocytes (F cells); and the levels of progesterone, human chorionic gonadotropin (HCG), and human chorionic somatomammotropin (HCS) in serial blood samples from women at different stages of pregnancy were determined. An increase was observed in the synthesis and the quantity of maternal HbF, reaching a peak at about 9-12 weeks gestation. A major peak in F-cell level was also detected at about 9-12 weeks, with two minor peaks appearing at about 16-20 and 22-24 weeks. Levels of HCG, HCS, and progesterone also varied during pregnancy. Timing of the rise and fall of HCG levels corresponded to that of maternal HbF levels, whereas levels of HCS and progesterone did not reach their peak until later stages of gestation when HbF level had returned to normal. Similar analysis conducted on patients with hydatidiform molar pregnancy revealed that the majority (greater than 95%) of these patients showed significant increases in HbF synthesis at the time of molar evacuation, but decreased to normal levels in approximately 30 days post-evacuation. A similar profile in the levels of HCG, but not progesterone and HCS, was observed. A positive correlation between levels of HCG and HbF can be established (correlation coefficient = 0.94). These data are in agreement with the hypothesis that HCG may act as a stimulus for the enhanced HbF synthesis in adults.

Changes in hemoglobin F levels in pregnant women unaffected by clinical fetomaternal hemorrhage

“…In this study, %Hb F level was significantly elevated during 1 st trimester compared with those during 2 nd and 3 rd trimesters, consistent with the results of previous studies in which the proportion of red cells containing Hb F peaked during pregnancy between 2 and 7 months of gestation [8,9]. Although elevation of %Hb F level occurs as a result of either FMH or an increase in the number of adult F cells [6], the increase in red cells containing Hb F during the earlier stages of pregnancy has been suggested to be due to an increased number of adult F cells [8,9].…”

“…Although elevation of %Hb F level occurs as a result of either FMH or an increase in the number of adult F cells [6], the increase in red cells containing Hb F during the earlier stages of pregnancy has been suggested to be due to an increased number of adult F cells [8,9]. However, fetal red cells entering the maternal circulation may contribute to some extent to the elevation of %Hb F level in the 1 st trimester.…”

Plasma γ-Globin Gene Expression Suggests that Fetal Hematopoietic Cells Contribute to the Pool of Circulating Cell-Free Fetal Nucleic Acids during Pregnancy

“…Fetal erythrocytes and trophoblasts derive from different cell types, and these cells have dissimilar functions. Therefore, our interpretation of the data is that transplacental trafficking of fetal hematopoietic cells, along with the physiologic increase in maternal ␥-globin synthesis during pregnancy, is likely to be responsible for the observed higher concentrations of ␥-globin mRNA in the plasma of pregnant women (7,11 ).…”

Fetal Rhesus D mRNA Is Not Detectable in Maternal Plasma

“…Wataganara et al (4 ) reported detection of ␥-globin mRNA in maternal plasma. However, expression of ␥-globin is not a fetus-specific phenomenon and is shared by maternal erythroid cells (5 ), and ␥-globin mRNA is readily detectable in nonpregnant individuals (4 ). In this study, we assessed whether rhesus D (RHD gene) mRNA derived from fetal erythroid cells is detectable in the plasma of rhesus D-negative pregnant women.…”