Infectious causes of miscarriage

The question of the etiological role of infection is widely debated in the literature. Some researchers believe that infection is one of the most significant causes of miscarriage, both sporadic and habitual, while others believe that for sporadic interruption, perhaps infection plays a role, and for the usual - no.

Extremely many works on the role of infection in preterm birth, premature release of amniotic fluid, showing that infection is the main cause of premature birth.

Infection is one of the leading factors in the interruption of pregnancy. Almost 42% of women with a habitual miscarriage have an istrmico-cervical insufficiency, even if the main cause of miscarriage is AFS.

And even with APS, the very development of autoimmune disorders is associated with a persistent viral infection.

Viral diseases during pregnancy can lead to anembrion, undeveloped pregnancy, spontaneous miscarriage, antenatal fetal death, fetal malformations (compatible and incompatible with life), intrauterine infection manifested in the postnatal period. Important importance in the nature of disorders caused by a viral infection has a gestation period in which intrauterine infection occurred. The shorter the gestation period, the higher the probability of stopping development and the formation of malformations. Infection of the fetus in later terms does not lead, as a rule, to the formation of gross developmental defects, but it can disrupt the functional mechanisms of differentiation of cells and tissues.

It is now established that viruses can be transmitted to the fetus in several ways, but the most important is the transplacental pathway of infection.

The placenta is a physiological barrier that prevents the virus from penetrating the fetus, but in the early stages of pregnancy, the rapidly growing cells of the emerging trophoblast that have a high level of metabolic processes are an excellent medium for the replication of viral particles that can have a direct damaging effect on the placenta.

In case of physiological pregnancy, cytotrophoblast cells do not express the antigen of the main histocompatibility complex and are immune-indifferent. If these cells express a virus, they become a trigger mechanism for activation of immune cells and a target for immune aggression, which exacerbates placenta damage and thereby disrupts the function of this organ. .

Transition of viruses through the placenta is greatly facilitated for various injuries to it, for example, in case of an interruption threat, in autoimmune disorders, toxicoses.

The placenta is permeable to virtually all viruses. Viruses with blood flow can reach fetal membranes, adsorb to them and infect the amniotic fluid, and then the fetus. Infection of the membranes and water can also occur with an ascending infection.

Of the most viral infections, the most common disease is influenza.

The risk of illness and mortality for pregnant women with influenza is higher than for non-pregnant ones, and the risk of mortality in epidemics is also higher. The incidence of miscarriages in patients, especially in the first trimester, is 25-50%. However, the frequency of fetal malformations is not increased in comparison with population data. Attention is drawn to the fact that among the prematurely giving birth to healthy, primiparous women, 30% had ARVI in the first trimester of pregnancy. In 35% of them, abnormalities of the placenta development - barrel placenta, marginal attachment of the umbilical cord, lobular placenta, etc. Have been noted. Due to the fact that there is an inactivated type A and B vaccine against the flu, there is no risk of vaccination for the fetus. In case of epidemics vaccination of pregnant women, especially pregnant women with extragenital diseases is recommended.

Treatment of influenza during pregnancy is permissible only non-pharmacological, home remedies, vitamins. The use of remantadine, amantadine is contraindicated in the I trimester, t. A teratogenic effect is possible. You can use viferon, vobenzim, immunoglobulins.

Rubella - during pregnancy the risk of rubella infection is not increased in comparison with nonpregnant women. When a woman is diagnosed in the first trimester of pregnancy, the risk of miscarriages and congenital anomalies is high, so pregnancy should be interrupted. Vaccination during pregnancy is contraindicated, because a live attenuated vaccine is used and a teratogenic effect is possible. According to WHO recommendations, testing of blood for the presence of antibodies to rubella is conducted outside of pregnancy for women of childbearing age. In the absence of antibodies, vaccination is carried out.

Measles - during pregnancy, the risk of the disease is not increased compared to non-pregnant women. The risk of termination of pregnancy in case of a mother's disease is increased, as is the case with the flu, but the anomaly of fetal development does not cause this infection. Vaccination is not carried out, because Live attenuated vaccine is used. For the prevention of severe disease on contact in the first 6 hours, the use of immunoglobulin (0.25 mg / kg body weight) is possible.

Poliomyelitis - in pregnancy, the risk of disease and its severity is increased. Up to 25% of the fetuses in affected mothers suffer poliomyelitis in utero, including the development of paralysis. But the anomaly of fetal development does not cause this virus. There is a live and killed vaccine against poliomyelitis. It is possible to vaccinate a pregnant woman with a vaccine killed during an epidemic.

Parotitis - the risk of the disease is not higher than outside of pregnancy. Low morbidity and mortality are typical. The risk of fetal anomalies is not confirmed. Vaccination during pregnancy is not carried out, because Live attenuated vaccine is used. Due to the fact that the disease does not go badly, passive immunization is not indicated.

Hepatitis A - RNA virus, oral-fecal route of infection. When pregnancy is almost no complications, if the disease is not difficult. There are no specific methods of treatment. To prevent severe infection, you can use immunoglobulin - 0.25 mg per kg of body weight. Possible vaccination in pregnancy for endemic areas.

Hepatitis B is a DNA virus, there are several varieties: HBAg, HBcAg, HBeAg. The routes of infection are parenteral, perinatal and sexual. Up to 10-15% of the population are chronic carriers of hepatitis B.

Pregnant infects the fetus in the process of delivery, when the blood enters the baby, so if the pregnant woman has hepatitis B antigen, monitor monitoring in childbirth from the fetal head is not recommended. When a child is born, the mother-carrier of the virus should wash the child, removing all contamination, administer the baby immunoglobulin (0.5 ml IM) and vaccinate on the first day of life and after a month.

Parvavirus - DNA virus - during pregnancy passes through the placenta, causing the fetus to have a non-immune swelling syndrome. Clinical picture of the mother - rash, arthralgia, arthrosis, transient aplastic anemia. 50% of women have antibodies against paravavirus. If the pregnant woman does not have antibodies, then the greatest risk of losing pregnancy is observed with the disease up to 20 weeks. Specific treatment is not. The edematous syndrome developed in the fetus is due to heart failure due to anemia. For the prevention of severe complications, it is recommended to use immunoglobulin, octagam 5.0 g intravenously 2-3 times is recommended.

Acute viral infections contribute to the sporadic termination of pregnancy. If there is a threat of interruption in such an acute infection, then maintaining the pregnancy is not appropriate.

Much more complex and controversial is the problem of persistent viral infection and habitual miscarriage. The likelihood that episodes of acute viral infection will occur with each subsequent pregnancy at the same time, leading to habitual miscarriage, is negligible. Theoretically, to be the cause of repeated loss of pregnancy, the infectious agent must persist, constantly being in the genital tract of the woman for a long time, and at the same time be asymptomatic to avoid detection.

Analysis of literature data and the experience of the department of miscarriage allows us to conclude that persistent infection, viral and bacterial, is one of the main factors of habitual miscarriage. Even in the absence of direct specific effect of infectious agents on the fetus, reproductive system disorders caused by their persistence in the endometrium, with the development of chronic endometritis, as well as concomitant endocrinopathies and autoimmune disorders lead to disruption of embryo / fetus development and termination of pregnancy.

The frequency of the morphologically verified, asymptomatically occurring inflammatory process in the endometrium in patients with habitual miscarriage is 64% regardless of the clinical pattern of abortion. The incidence of asymptomatic persistence of opportunistic microorganisms in the endometrium of women with an inflammatory genesis of miscarriage in the anamnesis is 67.7%.

A characteristic feature of the microenocenosis of the endometrium is the presence in them of associations of obligate-anaerobic microorganisms. In patients with an interruption in the type of undeveloped pregnancy, chronic endometritis is caused by the persistence of viruses (herpes simplex virus, cytomegalovirus, etc.).

What caused such a high incidence of persistence of infectious agents? On the one hand, there is evidence that the immune response to infection is deterministic, on the other hand, many viruses have an immunosuppressive effect. Thus, a vicious circle is created - activation of the infection causes an immunodeficiency state, and a decrease in immunity, in turn, contributes to the activation of the infection. Among the persistent viral infections, the most important are:

1. Herpes virus infections (cytomegalovirus, herpes simplex virus, herpes zoster).
2. Enterovirus infections (Coxsackie A, B).
3. AIDS virus.
4. Hepatitis B, C.
5. Adenovirus.

With the habitual miscarriage of pregnancy, the persistence of viruses was revealed: Coxsackie A - in 98% of patients (in control 16.7%), Coxsackie B - in 74.5% (in control 8.3%), entero-68-71 - in 47.1 % (25% in the control), cytomegalovirus in 60.8% (25% in the control), herpes simplex virus in 56.9% (control 25%), rubella in 43.1% (control 12, 5%), influenza C - in 43.1% (in control 16.7%), measles in 60.8% of patients (in control 16.7%).

Practically there are no patients with habitual miscarriage, which would not have the persistence of several viruses. In these conditions, it is not so much in persistent viruses as in the characteristics of the patient's immune system. Perhaps in such cases the prevalence of one of the persistent viruses, as it is observed with simple herpes, and then there may be a clinic of exacerbation of this infection. But, as a rule, clinics do not have a persistent viral infection. Changes in immune parameters due to the persistence of viruses can lead again to the activation of bacterial flora, the development of autoimmune disorders, etc., and when these pregnancies are interrupted, these secondary factors are taken into account and regarded as the cause of the interruption.

[1], [2], [3], [4], [5], [6]