What is the assessment of a 32-year-old woman, gravida (number of times pregnant) 2, para (number of viable births) 1, at 28 weeks gestation, with a normal prenatal course, no chronic medical conditions, and laboratory results showing rubella nonimmunity, Rh-negative blood type, and negative serologies for human immunodeficiency virus (HIV), rapid plasma reagin (RPR), hepatitis B surface antigen, and chlamydia?

From the Guidelines

This patient should receive Rh immune globulin (RhoGAM) at 28 weeks gestation because she is Rh-negative with a negative indirect Coombs test, as supported by the study published in the Annals of Emergency Medicine 1. The standard dose is 300 micrograms administered intramuscularly. She will need another dose within 72 hours after delivery if the baby is found to be Rh-positive. This preventive treatment is essential to avoid Rh sensitization, which occurs when an Rh-negative mother develops antibodies against Rh-positive fetal blood cells that may enter her circulation during pregnancy or delivery. Without prophylaxis, these maternal antibodies could cross the placenta in subsequent pregnancies and attack the red blood cells of an Rh-positive fetus, potentially causing hemolytic disease of the newborn, as demonstrated by the significant reduction in fetal mortality from Rh hemolytic disease after the introduction of a postpartum rhesus prevention program in the United Kingdom in 1969 1. The patient should also receive the rubella vaccine postpartum since she is currently non-immune, but vaccination must be deferred until after delivery as it contains live attenuated virus that is contraindicated during pregnancy. Her trace proteinuria is likely benign but should be monitored at subsequent visits to ensure it doesn't increase, which could suggest developing preeclampsia. Key points to consider in the management of this patient include:

• The administration of anti-D immunoglobulin to prevent alloimmunization in Rh-negative patients, as supported by the Canadian study of 1,216 Rh-negative patients delivering Rh-positive infants 1
• The importance of monitoring for signs of preeclampsia, such as increasing proteinuria
• The need for postpartum vaccination against rubella to protect against future infections.

From the FDA Drug Label

For antenatal prophylaxis, one full dose syringe of HyperRHO S/D Full Dose (1500 IU; 300 mcg) is administered at approximately 28 weeks’ gestation. The administration of Rho(D) Immune Globulin (Human) within 72 hours of a full-term delivery of an Rho(D) positive infant by an Rho(D) negative mother reduces the incidence of Rh isoimmunization from 12%–13% to 1%–2%.(9) Bowman and Pollock(11) have reported that the incidence of isoimmunization can be further reduced from approximately 1.6% to less than 0. 1% by administering Rho(D) Immune Globulin (Human) in two doses, one antenatal at 28 weeks’ gestation and another following delivery.

The patient is an Rh-negative mother at 28 weeks gestation. According to the drug label, she should receive a dose of Rh immune globulin (IM) at this time for antenatal prophylaxis. The recommended dose is one full dose syringe of HyperRHO S/D Full Dose (1500 IU; 300 mcg) 2.

From the Research

Patient's Condition

The patient is a 32-year-old woman, gravida 2 para 1, at 28 weeks gestation with no complications in her pregnancy so far. She has no chronic medical conditions and is Rh-negative.

Recommended Course of Action

• According to the study by 3, anti-D Ig 300 microg should be given routinely to all Rh-negative nonsensitized women at 28 weeks' gestation when fetal blood type is unknown or known to be Rh-positive.
• The study by 4 also supports the use of RhIg for the prevention of Rh immunization in RhD negative pregnant women carrying an RhD positive fetus.
• The administration of RhIG at 26-30 weeks' gestation has been shown to be highly effective in preventing maternal Rh alloimmunization, as reported in the study by 5.
• The patient's Rh-negative status and the current gestation period of 28 weeks indicate that she should receive anti-D Ig 300 microg to prevent Rh alloimmunization, as suggested by the studies by 3, 4, and 5.

Additional Considerations

• The study by 6 highlights the importance of antepartum RIG administration in preventing Rh isoimmunization and its sequelae.
• The study by 7 discusses the prevention and management of RhD isoimmunization, including the use of Rh immune globulin to prevent sensitization.
• It is essential to note that the patient's blood type is A, Rh-negative, and her indirect Coombs test is negative, which indicates that she has not been sensitized to Rh-positive blood. Therefore, the administration of anti-D Ig 300 microg at 28 weeks' gestation is a recommended course of action to prevent Rh alloimmunization.