Rubella in pregnancy
Rubella - a highly contagious illness, is usually observed in children and adolescents.Despite the effectiveness of modern vaccines against measles, rubella antibodies in 20% of women of childbearing age are absent.Currently, revealed that the rubella possible both acute and chronic and asymptomatic form of infection, which makes it dangerous in terms of spread and infection.
Rubella in pregnancy - Causes
Rubella virus - is an RNA virus belonging to the family Togaviridae.After viral entry into human cells is its replication in the cytoplasm of infected cells.The source of infection is a sick person one week before the rash and for 1-2 weeks after the onset of exanthema.Also nasopharyngeal mucus, the virus is excreted in faeces and urine, therefore, in addition droplet way possible and contact-household path through the infected objects.Particular epidemiological importance are those with subclinical infection, as well as children with congenital rubella (chronic carriers).
Rubella during pregnancy - diagnosis
Laboratory diagnosis.Postnatal rubella is diagnosed by detecting antibodies.Rubella IgM appear in the blood after 1 week after infection and persisted for 1 month, sometimes up to 3 months.IgG appear shortly after the IgM and persist for life.In rare cases (1-3%) of these antibodies are destroyed and are no longer identified with the passage of time (10-20 years after rubella).Such people may re-infection, but then always subclinical disease.To confirm the diagnosis of acute infection is considered to increase the detection of IgM or IgG titer in 4 times higher.
diagnosis of fetal rubella can be installed when a virus or the presence of rubella IgM in fetal blood by cordocentesis.Detection of IgG titers above the motherboard also suggests intrauterine infection.Detection of IgG titer equal to the parent, indicates only the transplacental transfer of maternal antibodies.
Home diagnostic problem often encountered in obstetric practice test positive for IgM in pregnant women without clinical manifestations.The reasons can be noted the following factors:
To explain the reasons the IgM requires differential diagnostic tests and follow-up studies credits.
In most cases, modern methods allow to determine the cause of the presence of IgM, so that you can limit the indications for prenatal diagnosis.
If the reason for the presence of IgM is not installed, it is necessary to expand the indications for prenatal diagnosis.With GSCHR implementation became possible to quickly detect the virus in the chorionic villi, amniotic fluid with the fence with their term of 11-19 weeks, and in fetal blood at term of more than 22-23 weeks.Up to 21 weeks Production IgM may be too low, before 22 weeks is impossible to rule out false negative results cordocentesis.Based on the accumulated experience of foreign authors recommended prenatal diagnosis from 11 th to 17 th week of pregnancy.Due to the high risk of acute rubella embryopathy when I trimester of pregnancy is necessary to consider the question of its termination.
Rubella during pregnancy - symptoms
Approximately 50% of children subclinical rubella, while most adults appear more or less pronounced symptoms.After an incubation period (11-21 days) appear fever, cough, conjunctivitis, headache, arthralgia and myalgia.A typical early symptom - an increase okolozaushnyh, neck and cervical lymph nodes.In adults in 35% of cases develop viral arthritis.Maculopapular rash appears first on the face, then on the trunk and extremities.Rash disappears in the same sequence - downwards.The disease is usually not dangerous.The disease duration from several days to 2 weeks.Rubella virus can be detected in blood, urine, feces, and discharge from the nose and throat.Determine the rise in serum antibody titer.Major complications - thrombocytopenic purpura in children (1: 3000), meningoencephalitis in young people (1:10 000).
observed after vaccination with attenuated infection reduced reproduction of the virus, sometimes with swelling of the lymph nodes and exanthema, transient arthralgia.Because of parenteral administration, the vaccine is no local production of IgA-antibody in the nasopharynx.Vaccination of seronegative women shortly before pregnancy or in the early stages, about 2% of fetal infection is fraught, however, of cases of child has not yet been observed.Reinfection after vaccination relatively frequent contact with a wild strain of the virus due to lack of local immunity in the nasopharynx.If reinfection occurs transient viral replication in the nasopharynx with limited or no viremia.Reinfection can lead to infection of the fetus, but only in exceptional cases it comes to embriopaty.
Rubella in pregnancy - for
rubella in pregnant women is the same as outside of pregnancy.The risk of miscarriage and fetal death is increased by 2-4 times.rubella virus crosses the placenta during maternal viremia.The virus can infect the chorionic epithelium, and the capillary endothelium of the placenta, fetal endocardium.Along with this, there is the spread of the virus on fetal organs, where the virus multiplies and persists for a long time.IgM formation occurs, since 10-13 weeks, IgG - 16 weeks, a IgA - 30 weeks of gestation.T-cell responses are beginning to "work" with 15-20 weeks of gestation.In
fetal serum infected with measles virus starting from 21-22 weeks of pregnancy, IgM-antibodies are detected in 94%.At birth, 98% of all children with rubella embryopathy are developed independently and maternal IgM antibody IgG.IgM-antibody formation after birth continues 6 to 8 months, it coincides with the duration of viral shedding in secretions from the throat and urine.
pregnancy has no adverse effect on the course of rubella.During the period of viremia in the mother virus can infect the placenta and to the development of platsentita transplatsentarno transferred to the fetus;It increases the risk of developing pregnancy, fetal death, spontaneous abortion, premature birth and stillbirth.
risk of fetal infection in previously vaccinated women from reinfection during the first 16 weeks of pregnancy is 8%, and the risk of rubella embriopaty extremely low in these cases.
embriopaty Clinical manifestations caused by rubella.rubella syndrome symptoms include the following:
Most of these symptoms occurs in children whose mothers suffered rubella in the first 12 weeks of pregnancy.But even if the child is born without defects, for a long time, the virus persists in the body of the child (under 2 years).Unfortunately, there are no specific antiviral therapy for this disease.
rubella in pregnant women - risk to the fetus
particularly dangerous for pregnant women, rubella due to the high probability of congenital fetal malformations.Upon infection with rubella virus multiplies in the respiratory tract mucosa, regional lymph nodes, followed by a period of viremia, the virus displays tropism for the skin, lymphoid and fetal tissue.The mechanism of teratogenic effects of rubella virus is still not fully recognized.Penetrating to the fetus, the virus causes a disturbance of the mitotic activity of embryonic tissue and chromosomal changes.In addition, the virus causes apoptosis, inhibits their division and may interfere with the blood supply to organs of the fetus, leading to delays in mental and physical development, microcephaly, and various malformations.
incubation period for postnatal rubella infection lasts 11 to 24 days.Isolation of the virus from the throat begins 10 to 12 days after infection and ends after the development of secretory IgA (3-4 days after onset of symptoms).Viremia reaches its highest level after 10-12 days after infection and last for a total of 5-7 days.It ends with the launch of a variety of cellular immune responses, and the appearance of antibodies in serum and nasopharynx.Thus, patients are infectious for about 7 days before to about 4 days after onset of the rash.The serum within 2-4 days after the onset of symptoms reveal IgM- and IgA-, and then the antibody IgG.Their level is maximal during the first 2 weeks.IgM- and IgA-antibodies remain in the body and are detected in smaller quantities for 4-8 weeks after the onset of symptoms.Approximately 3-5% of IgM antibodies can persist in the body for a long time.IgG antibodies remain in the body for life.It should be borne in mind that after a period of viremia, ending shortly after the rash appears, the second stage of the virus as part of the system of mononuclear cells.
Rubella in pregnancy - prevention
Prevention.Great success, it does not because of viral shedding from the pharynx 7 days before onset of symptoms (if they occur).For the passive prevention of immunoglobulin used against rubella.Its use is recommended seronegative women in contact with rubella in the first 16 weeks of pregnancy.To reduce the incidence of embryopathy caused by rubella, is necessary to study the serological status of women before pregnancy and vaccination of seronegative women for 2-3 months prior to the planned conception.At low titer antibodies protivokrasnushnyh (less than 15 IU / ml) should also be vaccinated.As with any live vaccine, rubella vaccine should not be administered during pregnancy, but pregnancy is not usually interrupted at random vaccination.
in seronegative women should double during pregnancy to investigate immunity to rubella (in the early stages of pregnancy, and after 16 weeks of pregnancy).In identifying IgM or IgG in the build-up of paired sera of up to 16 weeks of pregnancy is recommended termination of pregnancy due to the high risk of fetal malformations.If a woman refuses to terminate the pregnancy, it recommended the introduction of large doses of immunoglobulin protivokrasnushnogo.The introduction of this immunoglobulin is also recommended that seronegative pregnant women who had contact with patients with rubella.In the case of women with rubella infection after 4 months of pregnancy abortion is not shown due to the low risk of intrauterine fetal injury at this stage of pregnancy.When the disease rubella does not provide any special management of labor, or the postpartum period.