Rh Isoimmunisation

For Educational Purpose Only

Gynaeguru

🩸Blood Type & Sensitisation

Maternal Blood Group

Antibody Identified

Antibody Titer (IAT)

Paternal RhD Status

Positive

Negative

Unknown

🤰Pregnancy Details

Gestational Age (weeks)

Gravida

Para

Previous Affected Infant

Yes

Previous Hydrops / IUFD

Yes

Fetal RhD Genotyping (cfDNA)

RhD+

RhD−

Not done

〰️MCA Peak Systolic Velocity

Gestational Age (weeks)

MCA-PSV Measured (cm/s)

📐MCA-PSV Reference Values (Mari 2000)

GA (weeks)	Median (cm/s)	1.5 MoM — Threshold (cm/s)	1.29 MoM (cm/s)

💉Anti-D Immunoglobulin Dose Calculator

Calculate Anti-D Ig prophylaxis dose based on sensitising event and feto-maternal haemorrhage (FMH) estimation.

Indication

Gestational Age (weeks)

Kleihauer-Betke Result (%)

Maternal Blood Volume (mL)

ℹ️Kleihauer-Betke FMH Estimation

Estimated feto-maternal haemorrhage volume:

KB % Fetal Cells

Maternal Blood Volume (mL)

📅Add Monitoring Entry

Date of Visit

Gestational Age (weeks)

Antibody Titer

MCA-PSV (cm/s)

MoM

Notes

📋

No monitoring entries yet. Add the first entry above.

🧬Antibody Significance & Monitoring Trigger

Antibody	Significance	Titer Threshold	IUT Capable
Anti-D (RhD)	High	≥ 1:16	Yes
Anti-c	High	≥ 1:8	Yes
Anti-K (Kell)	High	Any detectable	Yes
Anti-E	Moderate	≥ 1:16	Rare
Anti-C	Moderate	≥ 1:16	Rare
Anti-Fya	Moderate	≥ 1:32	Rare
Anti-Jka	Moderate–High	≥ 1:16	Rare
Anti-M, Anti-N	Low	Usually not	No
Anti-P1	Low	—	No

📐Monitoring Frequency Guidelines

Risk Category	Criteria	Titer Monitoring	MCA Doppler
Low Risk	Titer < threshold, no prior affected baby	Every 4 wks	Not indicated until > threshold
Moderate Risk	Titer at or approaching threshold	Every 2–4 wks	Start at 18–20 wks, every 2–4 wks
High Risk	Titer > threshold or prior hydrops/IUFD	Every 1–2 wks	Weekly from 18–20 wks

💉Antenatal Anti-D Prophylaxis Dosing

Indication	Timing	Dose (IU)	Notes
Routine antenatal (RAADP)	28 wks (+ 34 wks if 2-dose)	1500 IU	Or 500 IU x2 regimen
Miscarriage < 12 wks	Within 72 hrs	250 IU	Threatened: clinical judgement
Miscarriage 12–20 wks	Within 72 hrs	500 IU	Kleihauer if > 20 wks
Ectopic pregnancy	Within 72 hrs	250 IU	All ectopics
Amniocentesis / CVS	Immediate post-procedure	500 IU	Repeat if further procedures
APH / Trauma	Within 72 hrs	500 IU min	Kleihauer to guide additional doses
Postnatal (RhD+ baby)	Within 72 hrs of delivery	500 IU min	Kleihauer mandatory
IUT / ECV	Post-procedure	500 IU	Check titre 6 wks later

⚠️Indications for Intrauterine Transfusion (IUT)

Primary indications:

• MCA-PSV > 1.5 MoM on serial measurements

• Fetal hydrops on ultrasound (ascites, pleural effusion, scalp oedema)

• Fetal anaemia confirmed on cordocentesis (Hb < 2 SD below mean for GA)

Procedure targets:

• Correct fetal Hb to 12–14 g/dL using O-negative, CMV-negative, irradiated blood

• Repeat IUT every 2–3 weeks based on rise in fetal Hb (estimated ~0.3–0.4 g/dL/day)

Timing of delivery post-IUT:

• 34–37+6 weeks depending on clinical course and number of IUTs

• Steroids if delivery before 34+6 weeks anticipated