HIV infection in young children most commonly arises as a result of mother-to-child transmission (MTCT). It is thought that only 1.5-2% of MTCT occurs transplacentally during pregnancy. The vast majority occurs due to maternofetal transmission of blood during parturition or postnatal breast-feeding.
All pregnant women are recommended screening for HIV infection, syphilis, hepatitis B and rubella in every pregnancy at their booking antenatal visit. If a woman declines an HIV test, this should be documented in the maternity notes, her reasons should be sensitively explored and screening offered again at around 28 weeks.
A negative maternal HIV test at booking does not preclude neonatal infection - maternal infection and seroconversion can occur at any time during pregnancy and lactation. This is well-documented in countries with a high prevalence of HIV and has been seen in the UK.
Risk of mother-to-child transmission (MTCT)
This is increased with:
Higher levels of maternal viraemia.
HIV core antigens.
Lower maternal CD4 count.
Primary HIV Infection occurring during pregnancy.
Chorioamnionitis.
Co-existing other sexually transmitted disease (and malaria - possibly).
Invasive intrapartum procedures, eg fetal scalp electrodes, forceps, ventouse.
Rupture of membranes (especially if delivery is more than 4 hours after the membranes ruptured).
Vaginal delivery.
Preterm birth
Female babies more likely to be infected early (transplacental/perinatal routes).
Advanced maternal age.
The firstborn of twins (born to an HIV-infected mother).
Factors that decrease risk of transmission are:
Higher levels of neutralising HIV antibody.
Elective Caesarean section.
Zidovudine (ZDV)
Less invasive monitoring and intrapartum procedures.
Management
Mother-to-child transmission (MTCT) of HIV infection can be greatly reduced through early diagnosis of maternal HIV infection.
Pregnant women should be offered screening for HIV early in pregnancy because appropriate antenatal interventions can reduce MTCT of HIV infection.
Interventions to reduce MTCT of HIV during the antenatal period include antiretroviral therapy, elective Caesarean section delivery and avoidance of breast-feeding after delivery.
These interventions can reduce the risk of mother-to child HIV transmission from 25-30% to less than 1%.
All pregnant women who are HIV-positive should be screened and appropriately treated for genital infections during pregnancy. This should be done as early as possible in pregnancy and repeated at about 28 weeks.
Presentation with symptoms or signs of pre-eclampsia, cholestasis or other signs of liver dysfunction during pregnancy may indicate drug toxicity, and early liaison with HIV physicians is essential.
Drug therapy
Women who require HIV treatment for their own health should take highly active antiretroviral therapy (HAART) and continue treatment postpartum. They may also require prophylaxis against pneumocystic pneumonia (PCP), depending on their CD4 lymphocyte count.
Women already taking HAART and/or PCP prophylaxis before pregnancy should not discontinue their medication.
Antiretroviral therapy is given to prevent MTCT and to prevent maternal disease progression. The optimal regimen is determined on a case-by-case basis.
Zidovudine (ZDV) is indicated for use in pregnancy for prevention of MTCT of HIV but single-agent ZDV therapy which does not suppress plasma viraemia to undetectable levels may allow the emergence of resistant virus.
Potent combinations of three or more antiretroviral drugs (HAART) have now become the standard of care. Women with advanced HIV should be treated with a HAART regimen. The start of treatment should be deferred until after the first trimester, if possible, and should be continued after delivery.
For women who do not require HIV treatment for their own health, HAART should be initiated between 20 and 28 weeks and discontinued at delivery. If they have a plasma viral load of less than 10,000 copies/ml and are prepared to be delivered by elective Caesarean section, an acceptable alternative is ZDV monotherapy initiated between 20 and 28 weeks, given orally, 250 mg twice daily, and intravenously started four hours before beginning the Caesarean section, continuing until the umbilical cord has been clamped. ZDV is usually administered orally to the neonate for four to six weeks.
Combination antiretroviral therapy maximises the chance of preventing transmission and represents optimal therapy for the mother but may increase the risk of drug toxicity to the fetus.
The use of antiretrovirals to reduce MTCT has resulted in resistant mutations and, in the Paediatric AIDS Clinical Trials Group Protocol, 15% of the women developed nevirapine-resistant mutations by 6 weeks' postpartum.
In sub-Saharan Africa, access to services is improving. In 2008, 45% of HIV-infected pregnant women received antiretroviral treatment compared with 9% in 2004.
All pregnant women are recommended screening for HIV infection, syphilis, hepatitis B and rubella in every pregnancy at their booking antenatal visit. If a woman declines an HIV test, this should be documented in the maternity notes, her reasons should be sensitively explored and screening offered again at around 28 weeks.
A negative maternal HIV test at booking does not preclude neonatal infection - maternal infection and seroconversion can occur at any time during pregnancy and lactation. This is well-documented in countries with a high prevalence of HIV and has been seen in the UK.
Risk of mother-to-child transmission (MTCT)
This is increased with:
Higher levels of maternal viraemia.
HIV core antigens.
Lower maternal CD4 count.
Primary HIV Infection occurring during pregnancy.
Chorioamnionitis.
Co-existing other sexually transmitted disease (and malaria - possibly).
Invasive intrapartum procedures, eg fetal scalp electrodes, forceps, ventouse.
Rupture of membranes (especially if delivery is more than 4 hours after the membranes ruptured).
Vaginal delivery.
Preterm birth
Female babies more likely to be infected early (transplacental/perinatal routes).
Advanced maternal age.
The firstborn of twins (born to an HIV-infected mother).
Factors that decrease risk of transmission are:
Higher levels of neutralising HIV antibody.
Elective Caesarean section.
Zidovudine (ZDV)
Less invasive monitoring and intrapartum procedures.
Management
Mother-to-child transmission (MTCT) of HIV infection can be greatly reduced through early diagnosis of maternal HIV infection.
Pregnant women should be offered screening for HIV early in pregnancy because appropriate antenatal interventions can reduce MTCT of HIV infection.
Interventions to reduce MTCT of HIV during the antenatal period include antiretroviral therapy, elective Caesarean section delivery and avoidance of breast-feeding after delivery.
These interventions can reduce the risk of mother-to child HIV transmission from 25-30% to less than 1%.
All pregnant women who are HIV-positive should be screened and appropriately treated for genital infections during pregnancy. This should be done as early as possible in pregnancy and repeated at about 28 weeks.
Presentation with symptoms or signs of pre-eclampsia, cholestasis or other signs of liver dysfunction during pregnancy may indicate drug toxicity, and early liaison with HIV physicians is essential.
Drug therapy
Women who require HIV treatment for their own health should take highly active antiretroviral therapy (HAART) and continue treatment postpartum. They may also require prophylaxis against pneumocystic pneumonia (PCP), depending on their CD4 lymphocyte count.
Women already taking HAART and/or PCP prophylaxis before pregnancy should not discontinue their medication.
Antiretroviral therapy is given to prevent MTCT and to prevent maternal disease progression. The optimal regimen is determined on a case-by-case basis.
Zidovudine (ZDV) is indicated for use in pregnancy for prevention of MTCT of HIV but single-agent ZDV therapy which does not suppress plasma viraemia to undetectable levels may allow the emergence of resistant virus.
Potent combinations of three or more antiretroviral drugs (HAART) have now become the standard of care. Women with advanced HIV should be treated with a HAART regimen. The start of treatment should be deferred until after the first trimester, if possible, and should be continued after delivery.
For women who do not require HIV treatment for their own health, HAART should be initiated between 20 and 28 weeks and discontinued at delivery. If they have a plasma viral load of less than 10,000 copies/ml and are prepared to be delivered by elective Caesarean section, an acceptable alternative is ZDV monotherapy initiated between 20 and 28 weeks, given orally, 250 mg twice daily, and intravenously started four hours before beginning the Caesarean section, continuing until the umbilical cord has been clamped. ZDV is usually administered orally to the neonate for four to six weeks.
Combination antiretroviral therapy maximises the chance of preventing transmission and represents optimal therapy for the mother but may increase the risk of drug toxicity to the fetus.
The use of antiretrovirals to reduce MTCT has resulted in resistant mutations and, in the Paediatric AIDS Clinical Trials Group Protocol, 15% of the women developed nevirapine-resistant mutations by 6 weeks' postpartum.
In sub-Saharan Africa, access to services is improving. In 2008, 45% of HIV-infected pregnant women received antiretroviral treatment compared with 9% in 2004.
No comments:
Post a Comment