Objective: To evaluate the results of management of very early fetal anemia (before 20 weeks of gestation) in cases of red-cell alloimmunization.
Methods: Retrospective study of the outcome of all in utero transfusions performed before 20 weeks of gestation and all pregnancies requiring an in utero transfusion before 20 weeks in our reference center from January 1990 through August 2011 in cases with severe alloimmunization.
Results: Twenty-five in utero transfusions were performed in 18 pregnancies in 16 patients during the study period. A vascular access was performed successfully in 22 of the 24 cases in which it was attempted. An intraperitoneal transfusion was necessary in two cases. Two in utero deaths attributable to the intravascular procedure occurred during attempts before 18 weeks of gestation and another, not associated with a transfusion, at 29 weeks. The overall survival rate was 83.3% (compared with 88.0% when the first in utero transfusion took place before 22 weeks). The risk of fetal loss for each transfusion was 8.0% before 20 weeks and 6.3% before 22 weeks. An intraperitoneal transfusion at 17 2/7 weeks allowed one fetus to survive until the first intravascular in utero transfusion could take place at 18 2/7 weeks.
Conclusion: Fetal anemia before 20 weeks remains at high risk of lethal complications compared with later gestational ages. Technical difficulties in a vascular access are mainly encountered before 18 weeks of gestation. At an earlier gestational age, intraperitoneal transfusion may gain the days necessary to perform an intravascular transfusion more safely.
Level of evidence: III.