Clinical beta notice
Disclaimer: These workbenches are the work of a single person, Dr. Ali Al-Ibrahim, they are all in beta and might have errors. Please report bugs, errors and improvements to Alioud16@gmail.com.
Fetal Transfusion Workbench
Expert MFM decision support for fetal anemia: red-cell alloimmunization, MCA Doppler surveillance, fetal hemoglobin/hematocrit estimation, intrauterine transfusion planning, donor blood requirements, serial scheduling, hydrops assessment, procedural documentation, and EMR-ready outputs.
Offline single-page app
MCA PSV + MoM
IUT volume engine
EMR ready
Fetal anemia risk assessment
Enter pregnancy, antibody, MCA Doppler and transfusion data.
MCA MoM
—
Enter GA and MCA-PSV
Anemia concern
—
MCA + hydrops + history
IUT volume
—
Needs EFW and fetal Hct
Next action
—
Enter clinical data
Integrated pathway
Immediate checklist
Management recommendation
Selected antibody interpretation
Clinically relevant antibody matrix
| Antibody | System | Risk | Fetal anemia? | Critical / trigger logic | Notes |
|---|---|---|---|---|---|
| anti-D | Rh | High | Yes - severe possible | RCOG historical: refer if >4 IU/mL; high risk >15 IU/mL. Many titre-based protocols use 1:16. | Use RhD cfDNA/fetal antigen pathway. If prior affected pregnancy, do not rely on titre. |
| anti-c | Rh | High | Yes - severe possible | RCOG historical: refer if >7.5 IU/mL; high risk >20 IU/mL. Can be clinically important below generic titre thresholds. | Major non-D cause. Anti-E may potentiate anti-c; escalate earlier. |
| anti-C | Rh | Moderate-high | Yes | Generic critical titre often 1:16 or 1:32 depending center. | Escalate if rising, prior affected fetus, or MCA abnormal. |
| anti-E | Rh | Moderate-high | Yes; severe cases reported | Generic titre can be unreliable; often 1:16 or 1:32. Lower concern threshold if anti-c coexists. | Do not dismiss anti-E at low titre if rising or prior disease. |
| anti-e | Rh | Moderate | Yes, less common | Generic critical titre framework. | Requires antigen-negative blood if clinically significant. |
| anti-Cw | Rh | Variable | Rare but reported | Generic critical titre framework if IgG/reactive at 37°C. | Usually less severe but not zero-risk. |
| anti-K | Kell | Very high | Yes - severe, marrow suppression + hemolysis | Refer once detected in most fetal medicine pathways; titre is a poor severity predictor. Some protocols flag 1:4 or 1:8. | Use fetal K antigen testing. MCA surveillance even with low titre if fetus at risk. |
| anti-k | Kell | Moderate-high | Yes - rare but possible | Generic critical titre framework; discuss transfusion medicine. | k-negative donor blood may be difficult; early blood-bank involvement. |
| anti-Kpa | Kell | Variable | Possible | Generic critical titre framework. | Rare; confirm IgG/thermal amplitude and fetal antigen risk. |
| anti-Kpb | Kell | Variable-high if fetus positive | Possible severe | Generic critical titre framework; product availability problem. | Kpb-negative blood is rare. |
| anti-Jsa | Kell | Variable | Possible | Generic critical titre framework. | Rare; population-dependent. |
| anti-Jsb | Kell | Variable | Possible | Generic critical titre framework. | Rare; donor matching challenge. |
| anti-Fya | Duffy | Moderate | Yes - usually mild/moderate, severe reported | Generic critical titre 1:16 or 1:32 depending center. | Fetal antigen risk and MCA if threshold/history. |
| anti-Fyb | Duffy | Low-moderate | Rare possible | Generic critical titre framework. | Usually less severe than Fya. |
| anti-Jka | Kidd | Moderate | Yes - severe/fatal cases reported | Generic critical titre framework. | Can be difficult serologically; neonatal late anemia possible. |
| anti-Jkb | Kidd | Moderate | Yes, less common | Generic critical titre framework. | Requires compatible antigen-negative blood. |
| anti-M (IgG / 37°C reactive) | MNS | Variable-high | Yes - severe cases reported, sometimes DAT-negative | Do not treat cold IgM anti-M as equivalent; if IgG/37°C reactive, use fetal medicine pathway. | Can suppress erythropoiesis; reticulocytopenia possible. |
| anti-N | MNS | Low-variable | Rare | Usually low risk unless IgG/37°C reactive and rising. | Confirm clinical significance with transfusion medicine. |
| anti-S | MNS | Moderate | Yes | Generic critical titre framework. | Severe cases uncommon but real. |
| anti-s | MNS | Moderate | Yes | Generic critical titre framework. | Can cause HDFN. |
| anti-U | MNS | High | Yes - severe possible | Generic critical titre framework; very early blood-bank planning. | U-negative blood is rare; high-risk pregnancy and transfusion challenge. |
| anti-Dia | Diego | Variable | Yes - rare severe cases | Generic critical titre framework. | Population-dependent; antigen-negative blood may be hard. |
| anti-Dib | Diego | Variable | Possible | Generic critical titre framework. | Rare. |
| anti-Lua | Lutheran | Low-variable | Usually mild/rare | Usually not a fetal anemia driver; consult blood bank if IgG significant. | More often transfusion compatibility issue. |
| anti-Lub | Lutheran | Variable | Possible rare | Generic framework if clinically significant. | High-prevalence antigen: donor matching issue. |
| anti-Coa | Colton | Variable | Possible | Generic framework. | Rare but can cause HDFN. |
| anti-Cob | Colton | Variable | Possible | Generic framework. | Rare. |
| anti-Yta | Cartwright | Low-variable | Rare | Usually transfusion medicine issue; fetal risk rare. | High-prevalence antigen. |
| anti-Doa / anti-Dob | Dombrock | Low-variable | Rare possible | Generic framework if IgG significant. | Rare; consult blood bank. |
| anti-Lea / anti-Leb | Lewis | Usually not fetal anemia | Generally no significant fetal anemia | No MCA/IUT pathway solely for isolated Lewis antibodies. | Usually IgM; poor fetal antigen expression. |
| anti-P1 | P1PK | Usually not fetal anemia | Generally no significant fetal anemia | No fetal anemia pathway unless unusual IgG clinically significant case. | Often cold IgM. |
| cold autoantibody / anti-I / anti-i | Ii | Usually not fetal anemia | Generally not HDFN pathway | No fetal anemia pathway alone. | Transfusion compatibility may be relevant. |
| Multiple antibodies | Mixed | Depends - often high | Yes if any clinically significant fetal antigen positive | Use the highest-risk antibody. Anti-c + anti-E, anti-K, or prior affected fetus escalates. | Blood-bank planning is critical. |
Critical titer rules are screening triggers, not guarantees. Anti-K, prior affected pregnancy, hydrops, rising anti-c/anti-E, and MCA trend should override a falsely reassuring titer.
MCA calculation
Median MCA PSV model used by app: median cm/s = exp(2.31 + 0.04643 × GA weeks). MoM = measured PSV / median. Use center-validated reference if your unit uses a different table.
Technique QA
- Use proximal third of MCA soon after its origin from the internal carotid artery.
- Keep insonation angle as close to 0 degrees as possible; avoid excessive angle correction.
- Use the highest reproducible PSV from good-quality waveforms.
- Avoid fetal breathing/activity and obvious compression artifacts.
- Interpret with caution after previous IUT and late gestation.
MCA risk gauge
Transfusion formula
V = FBV × (Target Hct − Initial Hct) / (Donor Hct − Target Hct)
Ordered volume = ((V + deadspace + sample loss) ÷ (1 − procedure loss fraction)) × (1 + hemolysis allowance)
If donor Hct is not clearly higher than target Hct, the calculation is invalid. Use concentrated fetal transfusion RBCs and confirm donor Hct with blood bank.
Calculated values
Donor blood specification
| Parameter | Default for fetal transfusion | Local verification |
|---|---|---|
| Component | Packed red cells for intrauterine fetal transfusion | Confirm product code with transfusion medicine |
| ABO/RhD | Usually O RhD-negative unless a center-specific compatible alternative is authorized | Required |
| Antigen matching | Negative for the maternal clinically significant antibody/antibodies | Required |
| Irradiation | Required / expected for fetal transfusion product | Required |
| Leukoreduction / CMV-safe | Use leukoreduced and CMV-safe according to local blood-bank policy | Required |
| HbS-negative | Commonly required or preferred for fetal/neonatal transfusion | Confirm |
| Storage age / washing | Local policy; document unit age, additive status, and whether washed/concentrated | Required |
| Donor Hct | High-Hct packed red cells; enter exact donor Hct into calculator | Required |
Procedure flow
Before
- Confirm fetal indication.
- Blood product physically available.
- Emergency delivery capability if viable.
- NICU and anesthesia aware.
During
- Ultrasound-guided cord/intrahepatic/IP access.
- Pre-Hb/Hct sample.
- Recalculate volume from measured value.
- Monitor FHR and puncture site.
After
- Post-Hb/Hct sample if feasible.
- Assess bleeding/bradycardia/contractions.
- Plan repeat MCA/IUT.
- Delivery timing review.
Complications to document
Serial scheduling logic
Non-immune fetal anemia differential
| Cause | Clues | Workbench action |
|---|---|---|
| Parvovirus B19 | Maternal viral illness/exposure, fetal hydrops, reticulocytopenia | Maternal IgM/IgG/PCR; MCA surveillance; IUT if severe anemia/hydrops |
| Fetomaternal hemorrhage | Reduced fetal movements, sinusoidal CTG, acute anemia, positive KB/flow cytometry | Urgent MCA/CTG; delivery vs IUT by GA and fetal status |
| Alpha-thalassemia major / Hb Bart's | Asian ancestry, both parents carriers, cardiomegaly, placentomegaly, hydrops | Genetics; consider fetal therapy/IUT pathway in selected programs |
| TAPS | MCDA twins: donor MCA high, recipient MCA low; no classic TTTS fluid discordance | Stage TAPS; consider laser/IUT/partial exchange/delivery by GA and stage |
| TRAP sequence | MC pregnancy with acardiac twin and pump twin cardiac strain | Assess pump twin compromise; fetal therapy center pathway |
| Fetal tumors / vascular malformations | Sacrococcygeal teratoma, chorioangioma, hepatic tumors, AV shunts | Map lesion, cardiac output, hydrops; consider fetal therapy/IUT/delivery |
| Other infections | CMV, toxoplasmosis, syphilis, malaria depending epidemiology | Targeted infectious workup; anemia management by severity |
| Hemorrhage | Intracranial, intra-abdominal, placental/cord bleed | Locate source; determine acute vs chronic; delivery/IUT decision |
This prototype uses original schematic teaching diagrams only. For production, embed your own de-identified images or confirmed open-license figures. Do not scrape copyrighted journal figures.
MCA PSV acquisition
Show proximal MCA, near-zero insonation angle, reproducible PSV waveform.
Severe fetal anemia physiology
Anemia lowers viscosity, raises cerebral PSV, and can progress to high-output failure and hydrops.
Intravascular IUT
Document access site, pre-Hct, calculated volume, actual volume, post-Hct, and complications.
Required production image library
- Normal MCA acquisition and poor-quality MCA examples.
- MCA MoM cases: normal, borderline, ≥1.5, hydropic severe anemia.
- Hydrops signs: ascites, pleural/pericardial effusion, skin edema, placentomegaly.
- Umbilical cord insertion access, free-loop access, intrahepatic access, intraperitoneal transfusion.
- TAPS donor/recipient MCA Doppler contrast.
- Blood product chain-of-custody and checklist screenshots for training.
Core references built into app
British Society for Haematology, 2025. Guideline for the investigation and management of red cell antibodies in pregnancy. Supersedes/absorbs scope from the older RCOG GTG 65.
RCOG Green-top Guideline 65. The Management of Women with Red Cell Antibodies during Pregnancy. Archived January 2026; useful historically for anti-D/anti-c IU thresholds and referral language.
Mari et al., NEJM 2000. Noninvasive diagnosis by Doppler ultrasonography of fetal anemia due to maternal red-cell alloimmunization; foundation of MCA-PSV MoM surveillance.
Zwiers, van Kamp, Oepkes, Lopriore, 2017. Review of IUT and non-invasive treatment options for HDFN.
Crowe et al., Transfusion 2023. How do we perform intrauterine transfusions?
Pasman et al., 2015. Intrauterine transfusion for fetal anemia due to red blood cell alloimmunization: 14 years' experience in Leuven.
Finning et al., Transfusion 2007. Cell-free fetal DNA genotyping for K and Rh C/c/E antigens.
Slaghekke et al. Twin anemia-polycythemia sequence diagnostic criteria and staging.
Important: exact antibody thresholds, donor blood unit age, CMV policy, HbS-negative policy, and target Hct must be locked to your hospital fetal therapy and transfusion medicine policy before clinical deployment.
Workbench Reference & About
Version: 1.0b
Guideline version: BSH 2025
Last reviewed date: 2026
Formula source: Mari 2000
Coefficient source: N/A
Validation notes: N/A
Known limitations: N/A
What changed in this version: Initial release.
© 2026 Dr. Ali Hussein Al Ibrahim. All rights reserved.