1. Management of the Rhesus
Negative Mother
Dr Shantala Vadeyar
MD, FRCOG, DM
Advanced Obstetric Ultrasound (RCOG / RCR)
Subspecialist Fetal & Maternal Medicine (RCOG)
Consultant Obstetrician, Fetal & Maternal Medicine
Kokilaben Dhirubhai Ambani Hospital, Mumbai
www.totalpregnancycare.com

2. Background
• Incidence of Rh neg individuals varies
with race
• Caucasians (whites) 15%
• Afro-Carribeans (blacks) 7-8%
• Asians 5%
• Chinese and Japanese 1%

3. What is the Rhesus factor?
• It is a Red blood cell
antigen
• Other Red cell
antigens include -
• A, B – blood groups
• Duffy, Kell, Kidd

4. Genetics of Rh factor
• C, D and E antigens
• D antigen is the most
important and determines
Rh positivity
• cDe is Rh positive
• Two alleles – heterozygotes
or homozygotes
Rh positive Rh neg
• Rh negative person has dd
genotype

5. Pathophysiology
in pregnancy
• Rh negative mother
• Carrying a Rh positive fetus
• Some Rh positive RBCs cross over into
the maternal circulation
• Since the mother has not been
exposed to these antigens,
• She makes antibodies to this
“D” antigen

6. Pathophysiology
of isoimmunisation
• These circulating “anti-D”
antibodies enter fetus
• They will attack fetal RBCs
that are rhesus positive
• This causes RBC destruction
(hemolysis)
• This leads to fetal anemia
• Fetus does not get
hyperbilirubimemia
• Manifests as hydrops and
fetal loss

7. Management of
Rh negative gravida
• Careful history
• Previous pregnancy losses
• h/o blood transfusions
• Check husband‟s blood
group and Rh factor
• Check anti-D antibodies Coomb‟s test
• If no antibodies at
„booking‟, then repeat
titres at 28, 36 weeks

8. Prophylactic Anti-D
• Prophylactic antenatal anti
D at 28, 34 weeks 300 IU
injection
• Following any episode of
antepartum haemorrhage
• Miscarriage, Ectopic
pregnancy
• Amniocentesis / CVS / FBS
• Delivery – normal and LSCS

9. Anti – D:
Mechanism of Action
• The Rh positive fetal
RBCs that enter the
maternal circulation
are destroyed by the
anti D
• Thus, the D antigen is
not allowed to be
presented to the
maternal immune
system
• Prevents „sensitisation‟

10. Rh Sensitised Pregnancy
Titres 4 weekly
Titres < 1:32 till 24 wks and 2
Rh antibodies wkly till term
positive Serial fetal MCA
Titres > 1:32 Dopplers every
1-2 wks

11. Middle Cerebral Artery

12. MCA Doppler- Rhesus isoimmunisation

13. MCA Doppler- IUGR

14. Rh Sensitised Pregnancy - 2
Fetal Blood
Sampling and
consider IUT
MCA PSV 1.5
MoMs and above
MCA Doppler If no facilities for
Velocimtery FBS,
amniocentesis
Peak Systolic
Velocity
MCA PSV less Monitor MCA PSV
than 1.5 Moms 1-2 wkly

15. Fetal assessment of hemolysis–
invasive procedures
• Amniocentesis and checking
ODD 450 to check level of
bilirubin in AF
• Fetal Blood Sampling and
checking fetal Haemoglobin
level

16. Amniotic fluid ODD 450

17. Intrauterine blood transfusion

19. Antenatal Steroids
• If preterm delivery <36 wks may be
predicted, then antenatal steroids must
be given to enhance fetal lung maturity
• 2 doses of betamethasone 12 mg
• 24 hours apart
• Careful blood sugar monitoring in GDM
• May also cause hyperacidity

20. Delivery
• Most commonly with Rh sensitised
pregnancies – LSCS
• May try induction of labour
• Continuous FHR monitoring
• Early recourse to LSCS is any doubts
• Neonatologists present at delivery

21. Neonatal Management
• Commonly need Phototherapy
• May need Exchange
Transfusion
• Bone marrow suppressed
if IUT
• Anemia – blood transfusion
• Haematinics long term
• Good long term outcome

22. Rhesus isoimmunisation-1
• Mrs KC, age 38, P1, 15 yr girl
• Rh negative, booking antibody
screen
• Anti D at 15 weeks- 11iu/ml
• Scan at 20 weeks- MCA
Doppler normal
• Repeat Anti D titres and
scans for MCA PSV every 2-3
weeks.
• 26 weeks- raised titres
20iu/ml and MCA PSV raised
to 1.5MoMs

23. Rh isoimmunisation-2
• Amniocentesis ODD450- below
action line
• 29, 30 weeks- MCA Doppler
normal
• 30 weeks- repeat
amniocentesis- slight increase
in ODD 450 levels, but below
action line
• 31 weeks- Steroids, MCA
Dopplers every week- within
1.5 MoMs- normal

24. Delivery
• 32 weeks-
amniocentesis- action
line
• Options- Intrauterine
transfusion v/s delivery
• 33+5 w- delivery- 2.2kg
female
• Exchange transfusions
and phototherapy
postnatally- discharged
2 weeks

25. THANK YOU