Intrauterine Transfusion Calculator

Fetal RBC & platelet transfusion volumes and procedure medications · Mandelbrot method

Patient inputs

1 · Estimated fetal weight

Most recent scan; rescan if > 7 days old.

2 · Current fetal hematocrit

Patient starting Hct, called from the lab.

3 · Target hematocrit

Goal after transfusion. Default 45.

4 · Donor unit hematocrit

From the bag, not the fetus. Use 78 if unknown.

RBC volume to transfuse

—mL

— mL packed red cells, intravascular

ΔHct (target − current): — Fetoplacental vol: — mL Cross-check (Giannina): — mL should be close

FPV = 1.046 + EFW×0.14 | RBC = FPV × (target − current Hct) / donor Hct

All doses scale linearly with EFW (per kg × EFW/1000).

Platelet transfusion ▸

Current platelet count

×10⁹/L

Donor platelet count

×10⁹/L

Target platelet count

×10⁹/L

Mandelbrot dilution formula, default target 300.

Platelet volume to transfuse

—mL

Platelet vol = FPV × (target − current) / donor platelet count

Reference: fetal Hgb by gestational age ▸

Gestational age

weeks

Mean Hgb: — g/dL −2 SD (anemia): — g/dL

Normative fetal hemoglobin; values between weeks are linearly interpolated.