Rubella is an infection of viral origin that usually cause mild frames, with few or no symptoms in most patients.She is a benign disease in the vast majority of cases, being less dangerous than the flu, for example.
Rubella, however, has a particularity that makes it an important public health concern: it is extremely dangerous to the fetus when taken over by the mother during pregnancy, especially in the first 3 months of pregnancy. For this reason, serology for rubella, used to make the diagnosis of this virus, should always be part of the requested exams during prenatal care.
In this article let’s stick to interpretation of serology against rubella in pregnancy. We explain what are IgG or IgM terms reagent, reagent and not indeterminate, and what are the implications for the mother and the fetus in each type of result.
→ If you seek information about the disease rubella, including transmission, symptoms and treatment with maternity jumpsuits from Physicscat, go to the following link: RUBELLA | Symptoms and diagnosis.
→ If you seek more information about the common examinations, prenatal we have the following articles:
– Toxoplasmosis In Pregnancy.
– Prenatal | Routine Laboratory Tests.
– Ultrasound In Pregnancy.
Meaning Of The Terms Serology, Igg And Igm
One of the most common ways to diagnose an infection is by serology, which is a blood test in which we can search for the existence or not of specific antibodies against certain diseases.
The logic behind the serology is the following: when we are infected by some germ, fungus, bacterium, parasite or viruses, our immune system gives samples of these microbes and use them to create specific antibodies against them. If you have never been exposed to a particular Microbe before, you do not have specific antibodies against it. On the other hand, if you have now or had at some point in life, we can find specific antibodies circulating in the blood stream.
As antibody production takes a few days to get ready, the patients who are having an infection for the first time need, initially, use other weapons other than immunological antibodies, to attack the invading agent. An example are the white blood cells, also called leukocytes, which are defense cells that can attack any type of infectious agent. In many cases, the disease can be mild enough to be controlled only with non-specific defense cells, before antibodies are ready.
Some diseases, however, can only be fully eliminated when the first specific antibodies arise. It is important to note that each group of antibodies is specific to a particular disease. Their antibodies against toxoplasmosis do not serve to combat measles, as well as antibodies against the chicken pox of nothing good against measles.
I will use the example of rubella, but the reasoning that I’ll develop from now serves for most infections.
Igm And Igg Antibodies
When you’re infected with a new infection, the first produced antibodies are immunoglobulins M, more known as IgM. Therefore, the presence in the blood of large quantities of IgM against rubella, for example, is an indicator that the infection was recently acquired. Soon, a serology with reagent for rubella IgM result indicates current infection.
When the patient is cured of the infection, the immune system to produce antibodies of the IgM type and produce immunoglobulins G, known as IgG. The IgG is an antibody memory, which remains present in the blood for the rest of his life. In this way, the next time the patient contact with rubella, the risk of developing the disease will be minimal, because from the first time, your immune system will have samples of specific antibodies against rubella.
Therefore, the presence of IgG antibody against rubella is a sign that the patient already had the disease at some point in life and now is immunized. The presence of antibodies of IgG type used to be called scar serological, IE, a brand that the patient was infected in the past.
IgG antibodies can be obtained through previous infection or vaccination. In fact, the goal of any vaccination is to induce the immune system to produce antibodies against a particular permanent infection. The development of antibodies of IgG type is a sign that the vaccination has been effective.
Interpretation Of Results Of Rubella Serology
When the patient makes a rubella serology, there are essentially 3 possible outcomes:
- IGM and IgG nonreactive.
- IGM IgG reagent and reagent not.
- Not IGM IgG reagent and reagent.
1-What Does The Result: Igm And Igg Nonreactive?
If in your rubella serology both IgM as IgG come as negative, it means you have no antibodies against rubella, i.e. never been exposed to this virus and is susceptible to infection. If you have been vaccinated, but the IgG is not your reagent, this means that vaccination was not effective, and this is an indication to repeat the vaccine.
A pregnant woman who has negative rubella serologies must be very careful not to get in touch with anyone infected, because, as she has no antibodies against rubella, she runs the risk of becoming infected during pregnancy.
2-What Does The Result: Igm Igg Reagent And Reagent Not?
As already mentioned, the IgM antibody comes up after a few days of infection by rubella. As the rubella virus takes about 2 to 3 weeks to manifest symptoms, in most cases, the IgM antibody reagent is already when the patient begins to manifest the disease. After 4 to 8 weeks, the production of IgM serology and shortens the becomes no reagent.
For this, a pregnant with positive serology for IgM means that she probably got infected with rubella virus in the last 2 to 6 weeks and is at risk of having a fetus with bad configurations, especially if the pregnancy is in the first quarter.
3-Which Means The Result: Igm Igg Reagent And Reagent Not?
The presence of a reagent for rubella IgG usually cause some confusion in pregnant women. Contrary to what most of the population lay person imagines, this result, if this still well in the beginning of pregnancy, it is best that pregnant women can have a look: If the woman has an IgG reagent, it only indicates that she has a scar, or be immune, is immune to rubella. This immunity may have been obtained by an ancient infection, before she got pregnant, or through prior vaccination. The fact is that the origin of the IgG little matter, the important thing is to know that this pregnant has a very low risk of getting rubella during your pregnancy, as it has antibodies against the virus.
It is necessary, however, one observation. The antibody IgG old infection, usually with more than 2 months, but he didn’t say exactly when enables us to that infection has occurred. Therefore, serology must be done at the first prenatal consultation can be interpreted correctly. Imagine a pregnant woman who does the serology in the fifth or sixth month of pregnancy and presents a positive IgG. If she has not had symptoms, we will have no way of knowing if that infection occurred years ago or arose in the first weeks of pregnancy.
IGM And Igg Against Rubella: Reagent, Reagent And Not Indeterminate
The reference values for the rubella serology may vary from one laboratory to the other. Time to interpret the result, not the value itself as important, but whether he is or not reagent reagent according to the reference values provided by the laboratory.
Picked up at random on the Internet the reference values of a particular Lab only to exemplify.
Reference Values For The Rubella Igg:
-No reagent: less than 5 IU/mL
Undetermined: 5 – the 15 IU/mL
-Reagent: more than 15 IU/mL
Reference Values For Rubella Igm:
-No reagent: less than 0.6 IU/mL
-Indefinite: 0.6 to 0.79 IU/mL
-Reagent: exceeding 0.79 IU/mL
In the example above, any patient with less than 5 IU/mL or less than 0.6 IgM IU/mL will have a result no reagent, namely, negative. Similarly, if the IgG is greater than 15 IU/mL or greater than IgM 0.79 IU/mL the reagent will result.
What Is An Indeterminate Result?
Indeterminate or inconclusive result occurs when the value of IgM or IgG is slightly changed, not being possible to say if there are antibodies in relevant quantities or not. In General, this problem occurs when some unidentified factor is interfering in the result. When this occurs, the ideal is to repeat the test. In most cases, when a patient with an indeterminate result repeats the serology, the new result comes as non-reagent.
Diagnosis Of Rubella In Pregnancy
The first prenatal consultation, all pregnant women should do the rubella serology to their Obstetricians have your science State of immunity against the disease. This first examination serves to know who is immunized and who is susceptible to disease.
The serology for rubella must also be requested if during pregnancy, the expectant mother have contact with any infected person or develop typical symptoms of rubella, such as fever, lymph enlargement and spots on the body.The diagnosis is made if the rubella serology to detect the presence of IgM reagent. Another way to make the diagnosis is by comparing the values of IgG antibodies at the time of symptoms and after 3 weeks. Even if the IgM remain negative if the IgG values rise more than 4 times in this range, this indicates that the symptoms were caused by rubella.
Reinfection By Rubella During Pregnancy
A person having rubella more than once is not common, but it’s not impossible. Similarly, it is not impossible that a person who has been vaccinated develop rubella. Therefore, if a pregnant woman who in the first prenatal exam had IgG positive develop a clinical picture similar to rubella, the hypothesis of a reinfection by rubella should be suggested. In these cases, the suggested conduct is as follows:
If the pregnancy has less than 12 weeks, a new serology should be performed. A significant elevation of IgG values in relation to the first examination strongly suggests the possibility of reinfection by rubella.Fortunately, the risk of bad-formations in reinfection is only 8%, well below the 80% in primary infection.
If pregnancy has already exceeded the 12 weeks, you don’t have to do anything, since the risk of bad-this phase formations is very low in cases of reinfection.
Rubella Vaccination For Pregnant Women With Igg Reagent Not
A simple measure to immunize pregnant women who present no IgG reagent, i.e. who are susceptible to rubella in pregnancy, vaccination during pregnancy. Unfortunately, the current rubella vaccine is made with live attenuated virus, which contraindicates the Administration during your pregnancy.
So the best way to prevent rubella in pregnancy is through mass vaccination of girls during childhood. If you have been vaccinated in accordance with the schedule of vaccination, the risk of having rubella in a future pregnancy becomes a lot shorter.
What To Do If The Pregnant Woman Have Rubella In Pregnancy
As the risk of serious training is extremely high in the first quarter, many countries, such as Portugal, allow abortion when pregnant women have the misfortune of contracting rubella exactly in the first weeks of pregnancy. In Brazil, however, abortion is not permitted in this situation. In these cases, there’s nothing to do, just hope the infection does not cause serious damage to the baby.
Acquired rubella after the 20th of pregnancy rarely causes bad formations, but can cause some problems, such as premature birth or low birth weight babies.
Toxoplasmosis in pregnancy