Anti-D immunoglobulin prophylaxis to optimize prevention of rhesus (Rh) alloimmunization in women
Hematological / Oncological, Metabolic / Endocrine, Obstetrics and Gynecology
Women who are Rhesus (Rh)-negative and exposed to fetal Rh-positive red cells are at risk for developing Rh alloimmunization putting a future Rh-negative fetus at risk of hemolytic disease of the fetus and newborn (HDFN).
Before the availability of anti-D immunoglobulin (anti-D Ig or Rho(D) immune globulin), HDFN was a major cause of morbidity and mortality.1
- If anti-D Ig is given appropriately at 28-30 weeks GA and following delivery of an Rh-positive infant, the risk of alloimmunization is reduced to 0.1% from 16%.
- In Canada, the product’s tradename is “WinRho” but is also known as RhoGAM.
- Can be given IM or IV route.
- Anti-D Ig has been used in Canada since 1968 with very few serious effects reported – no infections but allergic reactions may occur.
- Not known to be harmful to a baby during pregnancy/breastfeeding.
- All Rh-negative pregnant women should be offered routine prophylaxis with anti-D immunoglobulin (anti-D Ig), during their third trimester of pregnancy.1
- Evidence for benefit of prophylaxis following potentially sensitizing events in early pregnancy is less (particularly early in the first trimester with less fetomaternal blood exposure) but risks of administration are low therefore it is currently recommended.
Formerly dosed as micrograms (mcg) it is now “officially” International Units (IU).
- 1500 IU = 300 mcg WinRho .
- 250 IU = 50 mcg WinRho .
Anti-D immunoglobulin prophylaxis for RhD-negative women
RhD-negative women whose partner is, or might be D-positive, are candidates for anti-D Ig therapy as follows:
- A single dose of 300 mcg or 1500 IU anti-D Ig at 28 weeks GA.
- Another dose of 1500 IU within 72 hours of delivery of a D-positive newborn. If not given at delivery, anti-D Ig should be given as soon as possible up to 28 days after delivery. 2
- After any event that is associated with fetomaternal bleeding:
- Spontaneous, induced or threatened abortion.
- Blunt abdominal trauma.
- Ectopic pregnancy.
- Fetal death in the second or third trimester.
- Antepartum bleeding in the second or third trimester.
- Diagnosis of a hydatiform mole.
WinRho Dosing prophylaxis based on gestational age and exposure event:
- 250 IU (50 mcg) dose is recommended before 12 weeks gestation, although 1500 IU (300 mcg) can be administered if lower doses are not available.3.
- After 12 weeks, a 1500 IU (300-mcg) dose should be given.12.
Potentially sensitizing events
Amniocentesis, chorionic villous biopsy or cordocentesis.
Antepartum hemorrhage, uterine bleeding in pregnancy.
External cephalic version.
Abdominal trauma (including sharp, blunt, open and closed trauma).
Evacuation of a molar pregnancy.
In-utero therapeutic interventions including transfusion, surgery, insertion of shunts, laser).
Miscarriage or threated miscarriage.
Therapeutic termination of pregnancy.
Live birth (vaginal or Cesarean section).
Intra-operative cell salvage.
Fig 1. Comprehensive list of sensitizing events in pregnancy, adapted from Qureshi et al., 2014.
Quality Of Evidence?
We are highly confident that the true effect lies close to that of the estimate of the effect. There is a wide range of studies included in the analyses with no major limitations, there is little variation between studies, and the summary estimate has a narrow confidence interval.
We consider that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. There are only a few studies and some have limitations but not major flaws, there are some variations between studies, or the confidence interval of the summary estimate is wide.
When the true effect may be substantially different from the estimate of the effect. The studies have major flaws, there is important variations between studies, of the confidence interval of the summary estimate is very wide.
Strong evidence including practice guidelines from the Society of Obstetricians and Gynaecologists of Canada (SOGC) and the British Society of Haematology (BCSH).
OTHER RELEVANT INFORMATION
Rh Sensitization During Pregnancy, Information for patients.
– Health link BC
BCSH guideline for the use of anti-D immunoglobulin for the prevention of haemolytic disease of the fetus and newborn: Guidelines. Transfus Med.
Qureshi H, Massey E, Kirwan D, et al. 2014;24(1):8-20.
No. 133-Prevention of Rh Alloimmunization
Fung KFK, Eason E. .2018;40(1):e1-e10.
– J Obstet Gynaecol Can.
No. 181: Prevention of Rh D Alloimmunization.
American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Obstetrics in collaboration with Robert M. Silver, MD. 2017;130(2):e57-e70. doi:10.1097/AOG.0000000000002232
– Practice Bulletin Obstet Gynecol.
The purpose of this document is to provide health care professionals with key facts and recommendations for the diagnosis and treatment of patients in the emergency department. This summary was produced by the BC Emergency Medicine Network and uses the best available knowledge at the time of publication. However, healthcare professionals should continue to use their own judgment and take into consideration context, resources and other relevant factors. The BC Emergency Medicine Network is not liable for any damages, claims, liabilities, costs or obligations arising from the use of this document including loss or damages arising from any claims made by a third party. The BC Emergency Medicine Network also assumes no responsibility or liability for changes made to this document without its consent.
Last Updated Oct 08, 2021
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