What is HIV infection in pregnant women?
In recent years, the number of women of childbearing age has significantly increased among HIV-infected people. HIV infection in a pregnant woman invariably presents significant difficulties for the obstetrician. Doctors face the task of reducing the risk of transplacental transmission of the virus to the fetus and maintaining the health of the expectant mother. Conducting pregnancy should be carried out by an obstetrician and an infectious diseases virus.
Causes of HIV infection in pregnant women
AIDS is a disease associated with a pronounced violation of T-cell immunity in adults and T-and B-cell immunity in children. The causative agent of AIDS is the human immunodeficiency virus (HIV) – an RNA-containing virus. There are two types of HIV – HIV-1 and HIV-2. Of these, HIV-1 is most common. It has been proven that HIV-2 infection occurs less frequently, its incubation period is longer, it is less virulent than HIV-1. In HIV-2 infection, the disease develops in 4-10% of those infected, and in HIV-1 infection, in 20-40%.
A feature of the virus is the ability to synthesize on the basis of the actual RNA necessary for the reproduction of the virus of DNA using the enzyme reverse transcriptase (revertase). The virus has tropism for cells of the lymphoid series – T-helper cells (CD4), macrophages, monocytes and neurons, in which it is able to integrate into chromosomal DNA, persist for a long time, disrupt their function and cause immunity rearrangement. Replication of the virus begins after immune stimulation of T-lymphocytes due to reinfection or under the influence of other acute and chronic diseases. Rapid reproduction causes the death of CO4 cells. In this case, functional insufficiency of T-cell immunity occurs, which causes a violation of antigen-specific differentiation of B-lymphocytes and their polyclonal activation. This is manifested in an increase in the concentration of immunoglobulins in the peripheral blood, and the resulting dysfunction of B-lymphocytes with the development of their functional insufficiency causes a violation of the synthesis of specific antiviral antibodies. After reproduction in cells of the immune system, HIV spreads haematogenously throughout the body and can be isolated from any environment of the body. He is able to maintain his viability in plasma of a blood cell devoid of cellular elements for a long time, which explains the high probability of its transmission through a syringe.
HIV is heterogeneous, has a high degree of genetic variation, dies quickly when boiling, from the effects of disinfectants, but is resistant to ionizing radiation and UV radiation.
The source of the infection is AIDS patients and virus carriers. At the same time, the period of virus carriage can be very long (years), and during the first years after infection, the carrier can be seronegative due to the lack of virus replication. The ways of transmission are sexual (75% infected), transfusion (through infected blood products, drug addicts), transplacental, intrapartum, postnatal (through infected milk and with close household contacts between mother and newborn).
HIV has been isolated from many body fluids, including urine, saliva and tears, but so far only infections through blood, semen, vaginal secretions and breast milk have been described. Some danger may be “wet kisses.” The risk of sexually transmitted HIV infection increases with other STIs.
Symptoms of HIV infection in pregnant women
The incubation period for AIDS ranges from several months to 5 years or more. Transmission of HIV does not necessarily lead to the development of the disease. In 60-70% of those infected, the infection has been asymptomatic for a number of years. In 2-8% of those infected, the clinical signs of AIDS develop annually. At the same time, the disease has 6 stages: the incubation period, the acute stage of the disease, the latent period, persistent generalized lymphadenopathy, AIDS — the associated symptom complex and AIDS itself. On average, the time of development of AIDS from the moment of infection is 10 years, the disease can debut with any stage, including AIDS, it can stop at any stage without reaching AIDS.
Diagnosis of HIV infection in pregnant women
It is conducted based on the identification of risk factors or clinical symptoms with confirmation of the diagnosis using serological tests. PCR for detecting the viral genome in lymphocytes is not yet used as a standard diagnostic test. Serological studies carried out using enzyme-linked immunosorbent assay in combination with confirmatory tests. More specific tests are the determination of HIV proviral DNA, the viral load and the number of helper cells, the function of T cells.
In children, serodiagnosis is difficult due to frequent false-positive results due to transplacental transfer of maternal antibodies.
Treatment of HIV infection in pregnant women
Pregnancy and delivery in HIV-infected. The course of HIV infection may accelerate and worsen during pregnancy due to immunosuppression inherent in the gestational process. The course of pregnancy is also often complicated. Attention is drawn to the high incidence of cervical intranatal neoplasia, symptomatic candidiasis, and an increased incidence of preterm labor.
The most dangerous complication of pregnancy is perinatal infection of the fetus with HIV infection, which, without appropriate therapy, is observed in 30-60% of cases, regardless of the presence of symptoms of the disease in the mother. Vertical HIV infection can occur during pregnancy, in childbirth and postnatally. HIV can be transmitted both in the form of a cell-related virus and as a free virus. HIV-infected cells in the placenta also act as a source of infection. In this case, there are 3 ways of transferring the virus to the fetus.
Transplacental transfer of free virions as a result of various injuries of the placental barrier (placental abruption, placenta, FPN) with subsequent interaction of the virus with CO4 lymphocytes of the fetus.
- Primary infection of the placenta and accumulation of the virus in Gofbauer cells, followed by multiplication of the virus and its transition to the fetus.
- Intranatal infection of the fetus upon contact of the mucous membranes of the fetus with infected blood or secretions of the birth canal.
- Postnatally, from 15 to 45% of children from HIV-infected mothers are infected. Most of these women are unaware of the presence of the infection and mainly infect children during breastfeeding.
Maternal risk factors for vertical transmission: a large viral load of the organism with a high level of virus in the plasma, detection of a virulent HIV isolate, a low number of T-helper cells.
At the autopsy of spontaneous miscarriages in HIV-positive mothers, one can learn that HIV can cause intrauterine infection already in the first trimester. More than half of all cases of vertical transmission of infection occur immediately before or during childbirth, and antenatal infection in most cases occurs in the third trimester.
HIV infection of the fetus or newborn leads to the development of immunodeficiency, which is different from that of adults. Up to 5 years of life, AIDS develops in 80% of children infected with HIV perinatally. The first signs of intrauterine HIV infection are hypotrophy (in 75% of cases) and various neurological symptoms (in 50-70% of cases). Shortly after birth, persistent diarrhea, lymphadenopathy (90%), hepatosplenomegaly (85%), oral candidiasis (50%), developmental delay (60%) join. Chronic pneumonia and recurrent infections are common. Symptoms of CNS damage are associated with diffuse encephalopathy, cerebellar atrophy, microcephaly, and deposition of intracranial calcifications.
There are early and late HIV infection. About 20–30% of children who are vertically infected may have an early onset severe form of the disease — a rapidly progressing form. These patients have a high viral load at birth and in the first months of life, already in infancy they experience a rapid loss of helper T lymphocytes.
In 70-75% of vertically infected children, a slowly progressive form of infection is observed: low viral load at birth, a long number of stable helper cells, no clinical manifestations, or only mild symptoms (lymphadenopathy, mumps), and recurrent bacterial infections. The proportion of children with a slowly progressing form of the disease that has reached the AIDS stage is approximately 5-10% per year. In 5% of children, clinical and immunological symptoms do not progress. This is attributed to genetic factors, immunocompetence, and persistence of low-virulent HIV isolates.
The causes of death in young children with AIDS are generalized CMV infection or sepsis caused by gram-negative or opportunistic bacteria, in older children, as in adults, a combination of pneumocystosis with Kaposi’s sarcoma.
More recently, the detection of antibodies to HIV in the blood of a pregnant woman was an indication for termination of pregnancy due to the high risk of perinatal infection. However, at present, the prescription of a specific antiviral drug to pregnant women reduces the risk of intrauterine infection to 5-10%. Such antiviral drug in pregnant women is zidovudine – an analogue of HIV nucleosides. It is prescribed in doses of 300 to 1200 mg / day. No evidence of teratogenic effect of zidovudine has been established. Opportunistic infections are treated the same way as non-pregnant ones.
HIV infection in the mother is not an indication for cesarean section in women receiving antiviral drugs, since the risk of infection of the fetus during cesarean section and natural childbirth is about the same. In HIV-infected women who did not receive treatment during pregnancy, abdominal delivery is currently the method of choice.
In the case of delivery through the natural paths, the rules of labor for any viral infections should be followed: reduce the length of the anhydrous period and avoid using any obstetric manipulations that traumatize the skin of the fetus. To prevent infection at the time of childbirth zidovudine taken in capsules. To prevent postnatal infection, breastfeeding with HIV infection is contraindicated.
It is believed that when performing the following set of recommendations, the risk of infecting a child does not exceed 3%:
- antiretroviral therapy given to the mother during the second half of the pregnancy, to the newborn during the first 6 weeks of life;
- elective caesarean section;
- non-breastfeeding.
Prevention of HIV infection in pregnant women
Specific prevention, unfortunately, has not yet been developed. In order to reduce cases of perinatal infection in the Russian Federation, a mandatory examination of all pregnant women for HIV infection is made three times during pregnancy: when registered, with a period of 24-28 weeks and before childbirth. An HIV test of sexual partners of pregnant patients is also recommended. If at least one of the partners has HIV infection, they should independently decide whether to prolong such a pregnancy, knowing the degree of risk of infection of the fetus. Due to the prevalence of HIV infection and the risk of infection through breast milk, milk donation is prohibited in many countries.
Thus, in the prevention of vertical transmission of HIV, the following are used.
Obstetric activities:
- HIV testing;
- exclusion of invasive prenatal diagnosis in pregnant women with HIV;
- elective caesarean section before the onset of labor;
- during natural childbirth:
– exclusion of early amniotomy,
– disinfection of the birth canal,
– prevention of dissection and ruptures of the perineum.
Therapeutic activities:
- treatment of pregnant and newborn zidovudine.
Pediatric activities:
- adequate primary treatment in the delivery room;
- non-breastfeeding.