education

3.  Mechanism of action
 Preparation
 Dose
 Uses
 Side effects

4.  Immunoglobulin(IgG)
 From the plasma of Rh Neg men and women
sensitized with Rh positive cells
Mechanism of action
 The destruction of Rh antigen by macrophages
Preparation and Dose :
 It is available as 100 and 300µg (300 & 1500 IU)
ANTI-D

5. USE

6.  Prevention of Rh D Alloimmunisation
 Idiopathic Thrombocytopenic Purpura
ANTI-D

7. Prevention of Rh D
Alloimmunisation

8.  Includes five red cell proteins or antigens- C,c,D,E & e
 Rh negativity is absence of D antigen
 More than 200 D antigen variants exist
 The genes responsible are Rh D and Rh CE located in
the short arm of chromosome 1
 The critical titer is the level at which significant fetal
anemia could potentially develop.
 Generally between 1:8 and 1:32. If the critical titer for
anti-D antibodies is 1:16, a titer ≥1:16 indicates the
possibility of severe hemolytic disease.
Rhesus system

9.  The Rh D antigen has been reported on
fetal erythrocytes as early as 38 days from
fertilization
 or 7 3/7 weeks of estimated gestational age
FACTS

10.  Varies according to racial and ethnic origin
 15-17% in American whites and European
 1% in china
 5-10% in India
Incidence

11.  D-negative individuals may become sensitized
after a single exposure to as little as 0.1 mL of fetal
erythrocytes
Incidence

12. Causes of fetomaternal
haemorrhage

13.  Pregnancy loss
 Ectopic pregnancy
 Spontaneous or elective abortions
 Fetal death (any trimester)
Causes of fetomaternal
haemorrhage

14.  Procedures
 CVS (risk of FMH 14%)
 Amniocentesis (risk of FMH 2-6%)
 Fetal blood sampling/ Cordocentesis
 Evacuation of Molar pregnancy
Causes of fetomaternal
haemorrhage

15.  Other
 Delivery
 Trauma
 Placental abruption
 Unexplained vaginal bleeding during pregnancy
 ECV (2-6%)
 Manual removal of placenta
Causes of fetomaternal
haemorrhage

16.  Pregnancy loss
 Ectopic pregnancy
 Spontaneous or elective abortions
 Fetal death (any trimester)
 Procedures
 CVS (risk of FMH 14%)
 Amniocentesis (risk of FMH 2-6%)
 Fetal blood sampling/ Cordocentesis
 Evacuation of Molar pregnancy
 Other
 Delivery
 Trauma
 Placental abruption
 Unexplained vaginal bleeding during pregnancy
 ECV (2-6%)
 Manual removal of placenta
Causes of fetomaternal
haemorrhage

17.  Anti-D immune globulin should be given to all Rh
D-negative women
 Vaginal bleeding is heavy, repeated, or associated with
abdominal pain
 Particularly if these events around 12 weeks POG
Threatened abortion

18.  Partial
 Complete ??
Molar

19.  Alloimmunization has been reported to occur in
24% of women with a ruptured tubal pregnancy
 After 12 weeks of gestation, 300 micrograms Rh D
immune globulin is recommended
Ectopic Pregnancy

20.  2nd & 3rd trimester
 Yes
IUFD

21. WHY ALLOIMMUNIZATION IS
UNCOMMON

22.  Low prevalence of incompatible red cell antigens
 Insufficient trans placental passage of fetal
antigens or maternal antibodies
 ABO incompatibility leads to rapid clearance of
fetal erythrocytes before they elicit an immune
response
 Variable antigenicity : C, c, E, and e antigens
have lower immunogenicity than the D antigen
 Variable maternal immune response to the antigen
WHY ALLOIMMUNIZATION IS
UNCOMMON

23.  Anti-D immune globulin be withheld from a woman
undergoing postpartum sterilization ???
 NO
 Pregnancies occur despite sterilization procedures
Sterilization

24.  Initial
 Repeat
ICT

25. The grandmother theory

26.  Rh D negative female fetus exposed to Rh D
positive maternal RBCs develop sensitization
 When such individuals reaches adulthood, she
produce anti-D antibodies even before or early in
her first pregnancy
 So the fetus in the first pregnancy is jeopardized
by maternal antibodies –initially provoked by
grandmothers erythrocytes
The grandmother theory

27.  weak D as Rh D negative for transfusion
 Pregnant women are considered a candidate for
anti-D immune globulin
 Blood donors are interpreted to be Rh D positive
Du or weak D

28. CORD BLOOD INVESTIGATIONS

29.  Hb, PCV, Reticulocyte count
 ABO & RH
 Direct Coomb’s Test
 S Bilirubin
CORD BLOOD INVESTIGATIONS

30.  Half life of Anti D ranges from 16-24 days
 The standard IM dose of Anti D will protect the
average sized mother from fetal haemorrhage of
up to 30ml of fetal whole blood.
 The dose of Rh immunoglobulin calculated is
10 µg for 1 ml of fetal blood when fetomaternal
hemorrhage is > 30 ml
Anti-D Immunoglobulin

31.  If delivery occurs within 3 weeks of the standard
antenatal anti-D immune globulin administration,
the postnatal dose may be withheld in the absence
of excessive fetal–maternal hemorrhage
 If immune globulin is inadvertently not
administered following delivery, it should be given
as soon as the omission is recognized.
 There may be some protection up to 28 days
postpartum
 Anti D immune globulin may produce a weakly
positive 1:1 to 1:4 ICT titer in the mother.
Anti-D Immunoglobulin

32.  Immunoprophylaxis with Anti D within 72 hrs of
delivery reduced alloimmunisation rate by 90%
 Additionally provision of Anti D immune globulin
at 28wks gestation reduces 3rd trimester
alloimmunization rate from appx 2% to 0.1%
 Whenever there is doubt whether to give anti D, it
should be given. Even if it is not needed will not
cause any harm.
Anti-D Immunoglobulin

33.  Without prophylaxis Rh neg woman delivered of
Rh positive ABO compatible infant, has 16% likely
hood of developing alloimmunization
 2% - by the time of delivery
 7% - 6months post partum
 7% - in subsequent pregnancy (Sensibilisation)
 If there is ABO incompatibility Rh
alloimmunisation risk is appx 2% without
prophylaxis
Rh Alloimmunisation Risk

34.  less than 0.2% with routine antenatal
administration of anti-D immune globulin at 28
weeks of gestation
 Role of 2nd antenatal dose ??????
Rh Alloimmunisation Risk

35. ADDITIONAL DOSE

36.  Massive fetomaternal haemorrhage
 Abruptio placentae
 Multiple pregnancy
 Manual removal of placenta
 Trauma
 Placental chorioangioma
ADDITIONAL DOSE

37. Kleihauer-Betke test

38.  Kleihauer–Betke acid elution test relies on the
principle that fetal red blood cells contain mostly
fetal hemoglobin F, which is resistant to acid
elution, whereas adult hemoglobin is acid sensitive
 It lacks standardization and precision
 May not be accurate in conditions associated with
red blood cells containing an increased percentage
of hemoglobin F
 Sickle-cell disease
 Thalassemia
 Pregnancies at or near term, when the fetus has already
started to produce hemoglobin A
Kleihauer-Betke test

39. MAX DOSE Anti-D
Immunoglobulin

40.  If using an intramuscular preparation of anti-D
immune globulin, no more than five doses may be
given in a 24-hour period
 If using an intravenous preparation, two ampules—
totaling 600 μg—may be given every 8 hours
 Indirect Coombs test may be performed
 A positive result indicates that there is excess
anti–D immunoglobulin in maternal serum
MAX DOSE Anti-D
Immunoglobulin

41. TOCOLYTICS

42. TOCOLYTICS
 β-Adrenergic agonists
 Prostaglandin inhibitors
 Calcium channel blockers
 Magnesium sulfate
 Nitric oxide donor
 Oxytocin antagonists

43. INDICATIONS

44. INDICATIONS
 Therapeutic
 Preterm labour
 Uterine hyperstimulation caused by oxytocics
 Prophylactic
 ECV
 Intrauterine procedure like IUT

45. β-Adrenergic agonists

46. β-Adrenergic agonists
 Isoxsuprine (Duvadilan)
 Ritodrine
 Terbutaline
 Bind to β-adrenoceptors , activate enzyme
Adenylate cyclase , increase in the level of cAMP
reducing intracellular calcium level

47. Isoxsuprine HCl/ Duvadilan
 Oral 30-60mg/day in 3 doses
 IM 10 mg stat followed by two doses at 3 & 6 hrs
 IV dose

48. Ritodrine
 Selective β2 receptor agonist used specifically
as a uterine relaxant
 Dose-50mg in 45 ml of NS
 start @3ml/hr(50mcg/min)
 increase 3ml/hr every 10 min till contraction ceases or
 Systolic BP>100mm Hg
 Pulse>110/min
 Basal crepts
 Maximum dose of infusion-21ml/hr(350mcg/min)
 Switch to oral tablets(10mg)

49. Terbutaline
 Dose-250 mcg subcutaneous

50. SIDE EFFECTS β-Adrenergic
agonists

51. SIDE EFFECTS β-Adrenergic agonists
 Maternal
 Tachycardia, palpitations, restlessness, headache,
anxiety
 GI disturbances – nausea , vomiting and constipation
 Hyperglycemia (Ritodrine)
 Hypokalemia
 Myocardial ischemia
 Pulmonary edema
 Neonatal
Hypokalemia, hypoglycemia, hypotension, paralytic
ileus, intracranial hemorrhage

52. CALCIUM CHANNEL BLOCKERS
 Nifedipine
 Causes relaxation of myometrium
 Markedly inhibits the amplitude of spontaneous and
oxytocin-induced contractions
 10-20 mg 6-8 hrly
 Can be used in diabetics

53. S/E CALCIUM CHANNEL BLOCKERS
 Headache, dizziness
 Hypotension
 Flushing
 Constipation
 Ankle edema
 Cough
 Wheezing
 Tachycardia

54. Prostaglandin syntheses inhibitors
 Indomethacin
 The drug is available as 25mg capsules
 50mg loading dose orally or rectally then 25mg
6hrly
 Also used in idiopathic polyhydramnios
 Fetal risks
 Risk of premature closure of ductus arteriosus
leading to pulmonary hypertension
 Avoid use >48hrs and less than 32weeks

55. Magnesium sulphate
 Compete with calcium for entry into the cell at the
time of depolarization so there is decrease of
intracellular calcium
 4g slow IV then 2g IV per hr until contraction
ceases
 Narrow safety margin

56. Magnesium sulphate
 Neonatal effects of Magnesium -neuroprotective
a)stabilizes intracranial tone
b)minimizes fluctuations in cerebral blood flow
c)reduce perfusion injury
d)block calcium mediated intracellular damage

57. OXYTOCIN ANTAGONIST
 Atosiban ( tractocil )
 Nonapeptide
 Competitive antagonist of oxytocin
 Expensive drug
 Bolus 6.75mg over one minute, followed by
18mg/hr infusion for three hour then 6mg/hr
for up to 45 hrs
 Max dose 330mg

58. NITRIC OXIDE DONORS
 GTN patches
 Maternal headache, hypotension
 Neonatal hypotension

59. CONTRAINDICATIONS

60. CONTRAINDICATIONS TO TOCOLYSIS
 Severe Pre-eclampsia
 FGR
 Severe APH
 Fetal anomalies
 Chorioamnionitis
 Maternal heart disease