Antibody tests during pregnancy

The Rh factor and its role

The Rh factor (Rh) is a protein present on the surface of red blood cells (erythrocytes) that plays a key role in the transport of oxygen and carbon dioxide in the body. It is also involved in regulating immune processes, influencing the body's response to blood transfusions and organ transplants. 15% of people lack this protein, and their blood has a negative Rh factor (Rh-). When Rh-negative red blood cells enter the blood of an Rh-positive person (Rh+), the immune system may perceive them as foreign, leading to an Rh conflict.

Pregnancy and Rh-negative blood

If an Rh- woman becomes pregnant by an Rh+ man, she has about a 75% chance of having an Rh+ baby. However, this figure can vary depending on the genetic predisposition of the father, who may be homozygous (Rh+/Rh+) or heterozygous (Rh+/Rh-). In the latter case, the probability of having an Rh-negative baby drops to 50%. If the Rh factors of the mother and fetus do not match, an Rh conflict may occur—a situation in which the mother's immune system begins to produce antibodies that attack the fetus's red blood cells. This can lead to serious complications:

• Oxygen deprivation for the fetus;
• A high bilirubin level, causing jaundice;
• Cerebral damage;
• Development of a fetal hydrocele;
• fetal death in the most severe cases.

Screening for antibodies during pregnancy

At the first appointment with an obstetrician-gynecologist, the pregnant woman receives a list of mandatory tests, including blood type and Rh factor tests. In addition, the list of mandatory examinations includes

• General and biochemical blood analysis;
• Coagulogram (blood coagulation analysis);
• Screening for TORCH infections (a group of infections transmissible from mother to baby during pregnancy, delivery, or shortly after, including: Toxoplasma gondii, rubella, cytomegalovirus (CMV), herpes virus (HSV), and other infections such as syphilis);
• Blood glucose tests;
• Tests to detect potential genetic abnormalities in the fetus.
• If the future mother is Rh- and the father is Rh+, an additional blood test is performed to detect antibodies.

Frequency of antibody testing:

• At registration - at the beginning of pregnancy;
• In case of an uncomplicated pregnancy, repeat the test at 28 weeks;
• If antibodies are detected, regular dynamic monitoring is conducted.

Prevention of Rh conflict

To prevent Rh conflict, the introduction of anti-D immunoglobulins may be recommended to an Rh- mother carrying an Rh+ child. This medication prevents the formation of anti-Rh antibodies, thereby reducing the risk of complications.

• Even in the absence of antibodies, administration of anti-Rh immunoglobulins is recommended at 28-32 weeks;
• After delivery, if the newborn is Rh+, the immunoglobulin is repeated within 72 hours.

Characteristics of pregnancy with a negative Rh factor

An Rh-negative factor does not always lead to serious complications for the fetus, particularly during the first pregnancy. Indeed, the mother's immune system has not yet been sensitized to the Rh+ erythrocytes of the fetus, and the production of antibodies may be minimal or even absent. However, in subsequent pregnancies, the probability of an Rh conflict increases, as the mother's body already has an immune memory and can produce antibodies in large quantities.

• In the first pregnancy, the Rh conflict may be absent or weak;
• In repeated pregnancies, the amount of anti-Rh antibodies may significantly increase, raising the risk of complications.

In vitro fertilization (IVF) tests

When planning an in vitro fertilization (IVF), antibody tests play an important role in assessing the immune response of the future mother. Depending on the type of IVF, a comprehensive diagnostic test is performed:

• IVF with egg donation - immunological compatibility tests;
• IVF with double donation - monitoring possible immune reactions to reduce the risk of miscarriage;
• IVF with Rh conflict - close monitoring of antibodies to prevent complications.

Women with a negative Rh factor before IVF undergo additional examinations:

• Analysis of the anti-Rh antibody level;
• Evaluation of hormonal context;
• Immunological tests to identify potential risks;
• Ultrasound monitoring of the endometrium;
• Doppler measurement of blood flow in the uterine arteries.

To prepare for the successful implantation of the embryo, medications to improve the receptivity of the endometrium, antioxidants, and immunomodulatory therapy may be prescribed.

A comprehensive approach to managing pregnancy

The obstetricians and gynecologists at the “NatuvVtro” clinic are highly qualified and experienced in managing pregnant women with Rh conflicts. The clinic offers comprehensive diagnostics, including

• ULTRASOUND;
• Antibody analyses;
• Specialist consultations.

Make an appointment at a time that suits you to receive professional medical care!