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Oral Concurrent Session 3 - Fetus and Fetal Intervention

Oral Concurrent Sessions

Oral Concurrent Session 3 - Fetus and Fetal Intervention

(33) Fetal hematologic profile in monochorionic twins with anemia-polycythemia sequence undergoing serial transfusion and partial exchange

Wednesday, February 11, 2026

2:00 PM - 2:15 PM

Location: Summit 218 - 221

Submitting Author and Presenting Author(s)

Alexandra D. Forrest, MD (she/her/hers)

Maternal-Fetal Medicine Fellow
Johns Hopkins University
Baltimore, Maryland, United States

Coauthor(s)

Jena L. Miller, MD (she/her/hers)

Co-Director; Richard D. Wood Jr. Center for Fetal Diagnosis and Treatment
Children's Hospital of Philadelphia
Philadelphia, Pennsylvania, United States
MK

Michelle Kush, MD

Johns Hopkins Center for Fetal Therapy
Johns Hopkins University/BAltimore, Maryland, United States
Mara Rosner, MD, MPH (she/her/hers)

Assistant Professor
Johns Hopkins Center for Fetal Therapy
Johns Hopkins University/Baltimore, Maryland, United States
Ahmet A. Baschat, MBBCH, MD

Director, Johns Hopkins Center for Fetal Therapy
Johns Hopkins University
Johns Hopkins University, Maryland, United States

Objective:
Unequal red blood cell sharing in monochorionic twins with anemia-polycythemia sequence (TAPS) results in donor anemia and recipient polycythemia. Intrauterine transfusion (IUT) in the donor with or without partial exchange transfusion (PET) in the recipient is one treatment option. The fetal hematologic profile in TAPS has not been well characterized. We aimed to evaluate hematologic findings at diagnosis and in response to serial transfusions.

Study Design:
We conducted a single-center retrospective cohort study of fetuses with TAPS treated with IUT and PET. Fetal blood samples were analyzed at each procedure for hemoglobin, hematocrit, reticulocyte count and fraction, immature reticulocyte and platelet fractions, platelet count, and nucleated red blood cells. Initial donor and recipient values were compared and followed longitudinally.

Results:
11 patients with stage 2 TAPS underwent 150 procedures (78 donor IUTs, 71 recipient PETs, 1 blood sampling). Median gestational age at first procedure was 27+3 weeks (range 23+6–30+0) and at delivery 32+3 weeks (29+5–34+0), prolonging pregnancy by a median of 35 days (range 5–66). Donors had significantly lower hemoglobin, hematocrit, and platelets, and higher reticulocyte and immature platelet fractions than recipients (all p< 0.01). Some recipients had incomplete suppression of reticulocyte production. Serial transfusions were more effective in correcting donor hematologic abnormalities than they were in addressing those observed in the recipient.

Conclusion:
In this large series of fetal blood sampling in TAPS, donors demonstrated increased hematopoiesis with associated thrombocytopenia while polycythemic recipients largely exhibited downregulated erythropoiesis. The findings point to complex hematopoietic impacts of TAPS that may involve shared platelet and red-cell precursors in donors and paradoxical hematopoiesis in the recipient possibly due to transfusion of erythropoietin. These findings underscore the asymmetric physiology of TAPS and support serial transfusions as a strategy to prolong pregnancy in cases diagnosed beyond 26 weeks.