Question

The physician is worried that the fetus may be suffering from fetal erythroblastosis, a disease caused by A. rubella. B. point mutation of the beta-globin chain of hemoglobin. C. CFTR gene mutation. D. anti-Rh antibodies.

Short answer

D. anti-Rh antibodies.

Step-by-step solution

Understand the Condition

Identify what fetal erythroblastosis is and what causes it. Fetal erythroblastosis is also known as hemolytic disease of the newborn (HDN). It occurs when there is an incompatibility between the blood types of the mother and fetus.

Analyze Option A

Rubella is a viral infection that can cause congenital rubella syndrome but is not related to fetal erythroblastosis.

Analyze Option B

A point mutation of the beta-globin chain of hemoglobin causes sickle cell anemia, not fetal erythroblastosis.

Analyze Option C

A CFTR gene mutation causes cystic fibrosis, a genetic disorder unrelated to fetal erythroblastosis.

Analyze Option D

Anti-Rh antibodies are involved in fetal erythroblastosis. If an Rh-negative mother is exposed to Rh-positive fetal blood, she can produce anti-Rh antibodies that attack fetal red blood cells in subsequent pregnancies.

Verify the Answer

Reviewing all the options, the correct cause of fetal erythroblastosis is related to anti-Rh antibodies. Therefore, the correct answer is D.

Key concepts

hemolytic disease of the newborn

Hemolytic disease of the newborn (HDN), also called fetal erythroblastosis, is a serious condition. It occurs when there's an incompatibility between the blood types of the mother and the fetus. This incompatibility often leads to the destruction of the baby's red blood cells by the mother's immune system.

In HDN, the mother's antibodies attack the red blood cells in the fetus, causing them to break down or be destroyed. This can lead to severe anemia, jaundice, and even heart failure in the fetus. Understanding this condition is crucial for proper prenatal care.

Description of the symptoms can help understand the urgency and severity of HDN.

• Anemia in the fetus
• Jaundice in the baby after birth
• Poor muscle tone and lethargy
• Swelling due to fluid buildup

Timely medical intervention can prevent severe outcomes. Treatments may include blood transfusions and, in some cases, early delivery.

Rh incompatibility

Rh incompatibility is one of the main causes of hemolytic disease of the newborn. It happens when a mother's Rh blood type is different from her baby's.

To understand this, we must know there are different blood types, categorized by the presence or absence of the Rh factor, a specific protein on red blood cells. If you have the protein, you're Rh-positive. If you don't, you're Rh-negative.

Rh incompatibility occurs when:

• An Rh-negative mother carries an Rh-positive baby.
• If the baby's Rh-positive blood cells enter the mother's bloodstream, her immune system sees these cells as foreign and makes antibodies against them.

The first pregnancy usually isn't affected because the mother's immune system takes time to produce antibodies. However, in subsequent pregnancies, these antibodies can cross the placenta and attack the Rh-positive red blood cells of the fetus.
This is why prenatal care often includes blood type testing and monitoring for Rh incompatibilities.

Rh incompatibility can lead to serious complications for the baby, making early detection and management vital.

anti-Rh antibodies

Anti-Rh antibodies play a pivotal role in fetal erythroblastosis and Rh incompatibility. These antibodies form in an Rh-negative mother after exposure to Rh-positive fetal blood cells.

Here is how anti-Rh antibodies affect pregnancy:

• When an Rh-negative mother is sensitized by Rh-positive fetal cells, her immune system treats these cells as foreign and produces anti-Rh antibodies.
• In future pregnancies, these antibodies can cross the placenta and enter the fetal bloodstream.
• The antibodies then attack and destroy the Rh-positive fetal red blood cells, causing hemolytic disease of the newborn.

Medical strategies to prevent the formation of anti-Rh antibodies include administering Rh immunoglobulin (RhIg) shots. These are typically given at around the 28th week of pregnancy and after the delivery of an Rh-positive baby. The RhIg shots neutralize any Rh-positive fetal cells in the mother's bloodstream before her immune system can produce anti-Rh antibodies. This preventive measure is crucial for avoiding HDN in subsequent pregnancies.

maternal-fetal blood type incompatibility

Maternal-fetal blood type incompatibility isn't solely about the Rh factor mismatch; it also involves ABO blood type differences, although these are typically less severe than Rh incompatibility.

When a mother and fetus have incompatible blood types, it can lead to various issues:

• The mother’s immune system may identify fetal blood cells as foreign and produce antibodies against them.
• These antibodies can cross the placenta and attack the fetal red blood cells.

Unlike Rh incompatibility, which mostly concerns the Rh factor, ABO incompatibility involves differences in the main ABO blood groups (A, B, AB, and O). For example, an O type mother carrying an A or B type fetus could face ABO incompatibility.

Typically, ABO incompatibility is less severe and results in milder forms of hemolytic disease. Symptoms include mild jaundice in the newborn, which can usually be treated with phototherapy. Still, it's essential to test and monitor blood types during pregnancy to manage any incompatibilities effectively.
Understanding these different types of blood incompatibilities helps in administering the right preventive and therapeutic measures, ensuring both maternal and fetal health.