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ACOG antenatal dosing guidelines are based on clinical trials1,2:

  • 300 μg dose of anti-D at 28 weeks' gestation was studied in clinical trials3,4
  • This specific dose was expected to ensure 20-30 μg residual anti-D remained in maternal circulation at delivery3
  • When calculating the 300 μg dose, a mean elimination anti-D half-life of ~28 days was assumed4

RhoGAM's half-life aligns with ACOG Guidelines5

Not All Pregnancies Are Alike

Many factors are beyond your control:

  • The timing and amount of fetal-maternal hemorrhage (FMH) is unpredictable and can present without clinical suspicion6,7
  • There is natural, individual variability in the anti-D half-life8
  • The concentration of anti-D circulating in the maternal bloodstream late in the third trimester varies for each pregnancy8
  • The longer the half-life, the greater the residual level in circulation over time9 


References: 1. ACOG practice bulletin. Prevention of Rh D alloimmunization. Number 181, August 2017. Obstet Gynecol. 2017;130:e57-e70.3. 2. McMaster conference on prevention of Rh immunization. Hamilton, Ontario, Canada. 28-30 September, 1977. Vox Sang. 1979;36:50-644. 3. Bowman JM, Chown B, Lewis M, Pollock JM. Rh isoimmunization during pregnancy: antenatal prophylaxis. Can Med Assoc J. 1978;118:623-27. 4. Bowman JM, Pollock JM. Antenatal prophylaxis of Rh isoimmunization: 28-weeks’ gestation service program. Can Med Assoc J. 1978;118:627-30. 5. RhoGAM Ultra-Filtered PLUS [prescribing information], Fort Lee, NJ. Kedrion Biopharma Inc. 2019. 6. Sebring ES, Polesky HF. Fetomaternal hemorrhage: incidence, risk factors, time of occurrence, and clinical effects. Transfusion. 1990;30:344-357. 7. Pourbabak S, Rund CR, Crookston KP. Three cases of massive fetomaternal hemorrhage presenting without clinical suspicion. Arch Pathol Lab Med. 2004;128:463-65. 8. Bowman JM, Pollock JM. Failures of intravenous Rh immune globulin prophylaxis: an analysis of the reasons for such failures. Trans Med Rev. 1987;1:101-12. 9. Pelican EW. Half-life. In: Glossary of terms and symbols used in pharmacology. Boston, MA: Boston University School of Medicine. Boston University website. Accessed January 21, 2019.



  • RhoGAM® Ultra-Filtered PLUS [Rho(D) Immune Globulin (Human)] (300 μg) and MICRhoGAM® Ultra-Filtered PLUS [Rho(D) Immune Globulin (Human)] (50 μg) are immune globulins indicated for use in preventing Rh immunization for pregnancy and other obstetrical conditions in Rh-negative women unless the father or baby is conclusively Rh-negative, e.g., delivery of an Rh-positive baby irrespective of the ABO groups of the mother and baby, any antepartum fetal-maternal hemorrhage (suspected or proven), actual or threatened pregnancy loss at any stage of gestation and ectopic pregnancy.
  • In the case of postpartum use, RhoGAM and MICRhoGAM are intended for maternal administration. Do not inject the newborn infant.

Important Safety Information

  • RhoGAM and MICRhoGAM are contraindicated in Rh-positive individuals and in patients with a known history of anaphylactic or severe systemic reactions to the administration of human immune globulin products.
  • Severe hypersensitivity reactions may occur with the use of RhoGAM or MICRhoGAM. RhoGAM and MICRhoGAM should be administered in a setting where appropriate equipment, medications such as epinephrine, and personnel trained in the management of hypersensitivity, anaphylaxis, and shock are available.
  • Products made from human blood may carry a risk of transmitting infectious agents (e.g., viruses, the variant Creutzfeldt-Jakob disease [vCJD] and, theoretically, the Creutzfeldt-Jakob disease [CJD] agent).
  • After administration of Rho(D) immune globulin, a transitory increase of various passively transferred antibodies in the patient’s blood may yield positive serological testing results.
  • The most frequently reported adverse reactions in patients receiving Rho(D) Immune Globulin (Human) products are injection site reactions, such as swelling, induration, redness and mild pain or warmth. Possible systemic reactions are skin rash, body aches or a slight elevation in temperature. Severe systemic reactions include allergic reactions and hemolytic reactions.

You are encouraged to report adverse events of prescription drugs to the FDA. Visit or
call 1-800-FDA-1088.

Click here for the RhoGAM and MicRhoGAM Full Prescribing Information
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