Rh-sensitization

Fetomaternal hemorrhage (FMH), which can occur during pregnancy or delivery, triggers the Rh-negative mother's immune system to develop antibodies against the antigens in her baby's Rh-positive blood. This is called Rh-sensitization or alloimmunization. While this is the most common cause for Rh-sensitization, there are other ways in which sensitization can occur. For instance, Rh-sensitization occurs when someone with Rh-negative blood receives a transfusion of Rh-positive blood or blood components, such as platelets.

While the placenta-cell layer (trophoblast) usually prevents the fetus's blood from entering the mother's bloodstream, certain conditions can create FMH. The resulting Rh-sensitization can occur during any of these events:

  • Delivery
  • Miscarriage
  • Amniocentesis
  • Chorionic villus sampling
  • Placental abruption
  • Manual extraction of placenta
  • External version
  • Childbirth
  • Abortion

Typically, only a small number of antibodies are produced in the first pregnancy. During delivery, however, the mother's immune system becomes sensitized to the Rh factor. In subsequent pregnancies, the mother produces a greater number of antibodies, which cross the placenta to destroy the fetal red blood cells and create significant health risks for the baby. With each subsequent Rh-positive pregnancy, the mother's antibody reaction is faster, with potentially more severe consequences.

The mother needs to receive anti-D IgG treatment during the first pregnancy and immediately following delivery to thwart the danger that can occur in future pregnancies with an Rh-positive fetus.

  • Rh-negative mothers have a 1%–2% risk of being sensitized during the last trimester of pregnancy
    •      —At delivery, the Rh-negative mother has a 10%–15% risk of Rh-sensitization
  • An Rh-negative mother has about a 60% chance of having an Rh-positive baby if the father is Rh-positive1, 2
  1. Zipursky A, Paul V. The global burden of Rh disease. Arch Dis Child Fetal Ed. March 2011 Vol 96 No 2: F84-85.
  2. Source: U.S. Census Bureau, "2008 National Population Projections," August 2008.

Important Safety Information

Rhophylac®, Rho(D), Immune Globulin Intravenous (Human), is indicated for suppression of rhesus (Rh) isoimmunization in:

  • Pregnancy and obstetric conditions in non-sensitized, Rho(D)-negative women with an Rh-incompatible pregnancy, including routine antepartum and postpartum Rh prophylaxis and Rh prophylaxis in cases of obstetric complications, invasive procedures during pregnancy, or obstetric manipulative procedures.
  • Incompatible transfusions in Rho(D)-negative individuals transfused with blood components containing Rho(D)-positive red blood cells.

For suppression of Rh isoimmunization, Rhophylac can be administered IM or IV.

Rhophylac is indicated to raise platelet counts in Rho(D)-positive, non-splenectomized adult patients with chronic immune thrombocytopenic purpura (ITP). For the treatment of ITP, Rhophylac must be administered IV.

WARNING: INTRAVASCULAR HEMOLYSIS IN ITP
This warning does not apply to Rh0(D)-negative patients treated for the suppression of Rh isoimmunization.
Intravascular hemolysis leading to death has been reported in Rho(D)-positive patients treated for immune thrombocytopenic purpura (ITP) with Rho(D) Immune Globulin Intravenous (Human) products. Intravascular hemolysis can lead to clinically compromising anemia and multi-system organ failure, including acute respiratory distress syndrome (ARDS). Serious complications, including severe anemia, acute renal insufficiency, renal failure, and disseminated intravascular coagulation (DIC), have also been reported. Closely monitor patients treated for ITP with Rhophylac in a healthcare setting for at least 8 hours after administration. See full prescribing information for complete boxed warning.

Rhophylac is contraindicated in individuals with known anaphylactic or severe systemic reaction to human immune globulin products. Rhophylac is contraindicated in IgA-deficient patients with antibodies to IgA and a history of hypersensitivity.

Allergic or hypersensitivity reactions may occur with Rhophylac; early signs of hypersensitivity include generalized urticaria, chest tightness, wheezing, hypotension, and anaphylaxis.

Rhophylac is derived from human plasma. The risk of transmission of infectious agents, including viruses and, theoretically, the Creutzfeldt-Jakob disease (CJD) agent, cannot be completely eliminated.

Suppression of Rh Isoimmunization: For postpartum use following an Rh-incompatible pregnancy, Rhophylac should not be given to the newborn infant.

The most common adverse reactions in the suppression of Rh isoimmunization with Rhophylac are nausea, dizziness, headache, injection-site pain, and malaise.

Immune Thrombocytopenic Purpura: The most serious adverse reactions in patients receiving Rho(D) immune globulin have been observed in the treatment of ITP. ITP patients being treated with Rhophylac should be monitored for signs and symptoms of intravascular hemolysis, including back pain, shaking chills, fever, and hemoglobinuria. Potentially serious complications of intravascular hemolysis include clinically compromising anemia, acute renal insufficiency, and, very rarely, disseminated intravascular coagulation, and death.

The most common adverse reactions observed in the treatment of ITP are chills, pyrexia/increased body temperature, and headache. Mild extravascular hemolysis has also been observed. In patients with preexisting anemia, weigh the benefits of Rhophylac against the potential risk of increasing the severity of the anemia.

Immunoglobulin administration may transiently interfere with the immune response to live virus vaccines, such as measles, mumps and rubella

Please see full prescribing information.

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