Determining the volume of blood required for the correction of foetal anaemia by intrauterine transfusion during pregnancies of Rh isoimmunised women.
BACKGROUND
Severe anaemic foetuses of Rhesus (Rh) isoimmunised mothers are usually treated by intrauterine transfusion (IUT). It is helpful to determine the volume of blood necessary to raise the concentration of haemoglobin by 1.0 g/dL in response to intrauterine transfusions.


METHODS
In this cross-sectional, observational study we evaluated 107 first IUT for the correction of anaemia caused by haemolysis triggered by maternal Rh immunisation. The concentration of foetal haemoglobin was determined in umbilical cord blood before and after the IUT. The variation in foetal concentration of haemoglobin after transfusion was compared between groups of hydropic and non-hydropic foetuses, between groups of foetuses with different degrees of anaemia and with groups of gestational age less than or more than 28 weeks. The t-test for averages and ANOVA were used to compare average differences among the groups. p values less than 0.05 were considered statistically significant.


RESULTS
Fifty-five (61.4%) foetuses were found to be anaemic while hydrops was observed in 40 (44%) at the time of the IUT. The volume of red blood cell concentrate infused varied from 5 to 90 mL, with 11.2±1.5 mL being necessary to raise the circulating concentration of haemoglobin by 1.0 g/dL. The foetal response was not influenced significantly by either the degree of foetal anaemia (p=0.56) or the presence of hydrops (p=0.17). The foetuses with a gestational age of 28 weeks or less required a smaller volume of red blood cell concentrate than those with a gestational age of more than 28 weeks (9.3±5.4 mL and 13.4±4.8 mL, respectively; p<0.0001) in order to raise their concentration of circulating haemoglobin by 1.0 g/dL.


CONCLUSIONS
The volume of red blood cell concentrate necessary to correct anaemia in pregnancies complicated by Rh isoimmunisation must be considered carefully, since the response to the infusion of blood is peculiar in extremely premature infants. Hydrops and the degree of anaemia were not determinants of the change in the final concentration of circulating haemoglobin following the blood transfusion.
Foetal Medicine Centre, Obstetrics and Gynaecology Department, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Mônica Deolindo
MD
Santiago
Cezar Alencar de Lima
CA
Rezende
Antônio Carlos Vieira
AC
Cabral
Henrique Vitor
HV
Leite
Gabriel Costa
GC
Osanan
Zilma Silveira Nogueira
ZS
Reis
D000328:Adult; D000740:Anemia / Q000209:etiology / Q000628:therapy*; D001805:Blood Transfusion, Intrauterine / Q000379:methods*; D003430:Cross-Sectional Studies; D017707:Erythrocyte Transfusion / Q000379:methods*; D005260:Female; D005315:Fetal Diseases / Q000209:etiology / Q000628:therapy*; D005319:Fetal Hemoglobin / Q000378:metabolism*; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D012203:Rh Isoimmunization / Q000150:complications*; D055815:Young Adult
D005319:Fetal Hemoglobin