Analysis of antibodies and titers for Rh-conflict during pregnancy – treatment and prevention
The presence of a negative Rh factor in the expectant mother can become a serious problem if the future dad is Rh positive: the child can inherit the father’s Rh factor, and the possible result of such an inheritance is the Rh conflict, which is potentially dangerous for the baby and mother. The production of antibodies begins in the mother’s body by the middle of the 1st trimester, it is during this period that the manifestation of the Rh-conflict is possible.
How are Rh-negative mothers diagnosed, and is it possible to treat Rh-conflict in the process of carrying a baby?
The content of the article:
- When and how are antibodies tested?
- Treatment of Rh-conflict between mother and fetus
- How to avoid Rh-conflict?
Diagnostics of the Rh-conflict during pregnancy – when and how are tests for titers and classes of antibodies taken?
The doctor learns about the amount of antibodies in mother’s blood using tests called “titers.” The test indicators demonstrate whether there have been “meetings” of the mother’s body with “foreign bodies”, for which the body of the Rh-negative mother also accepts the Rh-positive fetus.
Also, this test is necessary to assess the severity of the development of hemolytic disease of the fetus, if it occurs.
Determination of titers is carried out through a blood test, which is taken without any special preparation of a woman, on an empty stomach.
Also, the diagnostics may include the following methods:
- Amniocentesis… Or the intake of amniotic fluid, carried out directly from the fetal bladder, with mandatory ultrasound control. With the help of the procedure, the blood group of the future baby, the density of the waters, as well as the titer of the mother’s antibodies to Rh are determined. The high optical density of the investigated waters may indicate the breakdown of the baby’s erythrocytes, and in this case, experts decide how exactly to continue the pregnancy.
- Cordocentesis… The procedure involves taking blood from the umbilical cord vein while monitoring an ultrasound probe. The diagnostic method allows you to determine the titer of antibodies to Rh, the presence of anemia in the fetus, Rh and blood group of the future baby, as well as the level of bilirubin. If the result of the study confirms the fact of negative rhesus in the fetus, then the mother is freed from further observation “in dynamics” (with negative rhesus, the baby never has a rhesus conflict).
- Ultrasound… This procedure evaluates the size of the baby’s organs, the presence of puffiness and / or free fluid in the cavities, as well as the thickness of the placenta and umbilical vein. In accordance with the condition of the expectant mother, ultrasound can be performed as often as the situation requires – up to the daily routine.
- Dopplerometry… This method allows you to assess the performance of the heart, the level of blood flow rate in the umbilical cord and blood vessels of the baby, and so on.
- Cardiotocography… Using the method, it is determined whether there is fetal hypoxia, and the reactivity of the baby’s cardiovascular system is also assessed.
It is worth noting that procedures such as cordocentesis and amniocentesis by themselves can lead to an increase in antibody titers.
When is antibody testing done?
- In the 1st pregnancy and in the absence of miscarriages / abortions: once a month from the 18th to the 30th week, twice a month from the 30th to the 36th week, and then once a week until the very birth.
- In the 2nd pregnancy: from the 7-8th week of pregnancy. When titers are detected no more than 1 to 4, this analysis is repeated once a month, and when the titer increases, it is 2-3 times more often.
Experts consider the norm in “conflict” pregnancy titer up to 1: 4…
The critical indicators include credits 1:64 and up…
If, before the 28th week, antibodies were not detected in the mother’s body at all, or in a value not exceeding 1: 4, then the risk of developing a Rh-conflict does not disappear – antibodies can manifest themselves later, and in rather large quantities.
Therefore, even with a minimal risk of Rh-conflict, specialists are reinsured and, for preventive purposes, inject the expectant mother at the 28th week of pregnancy anti-rhesus immunoglobulin Dso that the female body stops producing antibodies that can destroy the baby’s blood cells.
The vaccine is considered safe and harmless to mom and baby.
Re-injection is done after childbirth in order to avoid complications in subsequent pregnancies.
- If the blood flow velocity exceeds 80-100, doctors prescribe an emergency caesarean section to avoid the death of the baby.
- With an increase in the number of antibodies and the development of hemolytic disease, treatment is carried out, which consists in intrauterine blood transfusion. In the absence of such an opportunity, the issue of pre-term birth is resolved: the formed lungs of the fetus allow the stimulation of labor.
- Purification of maternal blood from antibodies (plasmapheresis). The method is used in the 2nd half of pregnancy.
- Hemisorption. A variant in which, with the help of a special apparatus, mother’s blood is passed through filters to remove toxic substances from it and purify, and then return (purified) back to the vascular bed.
- After the 24th week of pregnancy, doctors may prescribe a series of injections to help the baby’s lungs mature faster for spontaneous breathing after an emergency delivery.
- After childbirth, the baby is prescribed a blood transfusion, phototherapy or plasmapheresis in accordance with his condition.
Usually, Rh-negative mothers from a high risk group (approx. – with high antibody rates, if a titer is detected at an early stage, in the presence of the first pregnancy with Rh-conflict) are observed in the JC only until the 20th week, after which they are sent to the hospital for treatment.
Despite the abundance of modern methods of protecting the fetus from mother’s antibodies, delivery remains the most effective.
As for intrauterine blood transfusion, it is carried out in 2 ways:
- The introduction of blood under the control of ultrasound into the abdomen of the fetus, followed by its absorption into the bloodstream of the child.
- Injection of blood through a puncture with a long needle into the umbilical vein.
Prevention of Rh-conflict between mother and fetus – how to avoid Rh-conflict?
Nowadays, anti-Rh immunoglobulin D is used for the prevention of Rh-conflict, which exists under various names and is known for its effectiveness.
Preventive actions are carried out for a period of 28 weeks in the absence of antibodies in mother’s blood, given that the risk of contact of her antibodies with the baby’s erythrocytes increases during this period.
In case of bleeding during pregnancy, using methods such as cordo- or amniocentesis, the administration of immunoglobulin is repeated to avoid Rh-sensitization during subsequent pregnancy.
Prevention by this method is carried out, regardless of the outcome of pregnancy. Moreover, the dose of the drug is calculated in accordance with the blood loss.
- A blood transfusion for an expectant mother is possible only from a donor with the same rhesus.
- Rh-negative women should choose the most reliable methods of contraception: any method of terminating a pregnancy is the risk of antibodies in the blood.
- After childbirth, it is imperative to determine the baby’s rhesus. In the presence of a positive rhesus, the introduction of anti-rhesus immunoglobulin is indicated, if the mother has low antibodies.
- The introduction of immunoglobulin to the mother is indicated within 72 hours from the moment of delivery.
Bologny.ru warns that this article will in no way replace the relationship between doctor and patient. It is for informational purposes only and is not intended as a guide for self-medication or diagnosis.
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