A 27-year-old woman, gravida 3 para 1 aborta 1, at 20 weeks gestation comes to the office as she is concerned that she might be at risk for hemolytic disease. She just learned that her sister-in-law's second baby has hydrops fetalis due to Rh(D) incompatibility and is concerned that this could happen to her second baby as well. The patient's pregnancy has been uncomplicated to date. The patient is Rh(D) positive and her husband is Rh(D) negative. Their 3-year-old son is healthy, and he is Rh(D) positive. A year prior, the patient had a missed abortion requiring suction curettage. She has no chronic medical problems and no other surgeries. The patient is taking a prenatal vitamin and does not use tobacco, alcohol, or illicit drugs. Vital signs are normal. Fetal anatomic ultrasound a week prior demonstrated an echogenic intracardiac focus but no other abnormalities. Which of the following is the most accurate statement to the patient regarding hemolytic disease due to Rh(D) incompatibility?

Question

A 27-year-old woman, gravida 3 para 1 aborta 1, at 20 weeks gestation comes to the office as she is concerned that she might be at risk for hemolytic disease.  She just learned that her sister-in-law's second baby has hydrops fetalis due to Rh(D) incompatibility and is concerned that this could happen to her second baby as well.  The patient's pregnancy has been uncomplicated to date.  The patient is Rh(D) positive and her husband is Rh(D) negative.  Their 3-year-old son is healthy, and he is Rh(D) positive.  A year prior, the patient had a missed abortion requiring suction curettage.  She has no chronic medical problems and no other surgeries.  The patient is taking a prenatal vitamin and does not use tobacco, alcohol, or illicit drugs.  Vital signs are normal.  Fetal anatomic ultrasound a week prior demonstrated an echogenic intracardiac focus but no other abnormalities.  Which of the following is the most accurate statement to the patient regarding hemolytic disease due to Rh(D) incompatibility?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bf7d_b67a_8f63_5d2782f2e985_MD0005_00 Rh(D) incompatibility is possible only in an Rh(D)-negative mother and Rh(D)-positive father. It occurs when an Rh(D)-negative mother is exposed to the Rh(D) antigen, typically from fetomaternal hemorrhage in a prior pregnancy with an Rh(D)-positive fetus. The mother then produces IgG anti-D antibodies that cross the placenta and destroy Rh(D)-positive fetal red blood cells (eg, hemolysis) in a subsequent pregnancy. When Rh(D) incompatibility is unrecognized or untreated, alloimmunization can develop, resulting in hemolytic disease of the fetus or newborn. Disease ranges from mild anemia to severe hydrops fetalis. Progression of disease occurs when severe fetal anemia results in cardiac failure and subsequent edema (eg, pleural and pericardial effusions, ascites). Serial ultrasounds monitor the progression of fetal anemia, which can be treated with in utero red blood cell transfusions. This patient is Rh(D) positive; there is no risk of hemolytic disease to her newborn due to Rh(D) incompatibility. Regardless of the baby's blood type, the mother will never produce antibodies against the Rh(D) antigen (Choice C). However, antibodies to less common antigens [eg, Kell, Rh(c), Rh(E)] can also cause hemolytic disease; therefore antibody screening is performed in all pregnant women regardless of Rh(D) status. (Choice A) Maternal Rh(D) alloimmunization is diagnosed when an antibody screen and titers are positive for anti-D. In patients with elevated titer levels (>1:8), serial ultrasounds are performed to monitor for signs of anemia and hydrops fetalis. Fetal anemia can be treated with intrauterine fetal transfusion in an attempt to prevent the development of hydrops fetalis. (Choices B and D) When a mother is Rh(D) negative and a father is Rh(D) positive, there is a risk of hemolytic disease if the mother has been previously exposed to Rh(D) antigens (eg, prior pregnancy, blood transfusion). Rh(D)-negative patients can decrease the risk of an infant with hemolytic disease by receiving anti-D immune globulin [eg, Rho(D) immune globulin] during each pregnancy, including abortions and ectopic pregnancies. Educational objective: Hemolytic disease of the newborn due to Rh(D) incompatibility is possible only in an Rh(D)-negative mother and Rh(D)-positive father. References: Red cell alloimmunization in RhD positive pregnant women and neonatal outcome. (http://www.ncbi.nlm.nih.gov/pubmed/27324408) Hemolytic disease of the fetus and newborn: modern practice and future investigations. (http://www.ncbi.nlm.nih.gov/pubmed/27397673)

A 27-Year-Old Woman, Gravida 3 Para 1 Aborta 1, at 20