HIV in pregnancy: identification of intrapartum and perinatal HIV exposures

Question 1

What is the vertical transmission rate for HIV?

Answer 1

• current vertical transmission rate: 2%

* No interventions in pregnancy: as high as 25%

Question 2

• Risk factors for vertical transmission:

Answer 2

• late or no prenatal care **
• recent illness suggestive of HIV seroconversion **
• injection drug use
  
  • especially high risk if mother has acute or early untreated infection
• regular unprotected sex with partner known to have HIV (or at significant risk of HIV)
• diagnosis of STI in pregnancy
• emigration from HIV endemic area
• recent incarceration
  Most transmission at time of delivery; some occur in utero
• additional risk if newborn breastfed
  Toxicity from in utero exposure to ARVs is a potential complication

Question 3

What is the standard approach to HIV diagnosis in adults?

Answer 3

• Step 1: HIV antibodies by ELISA
• Step 2: Retest sample for HIV antibodies by Western Blot for confirmation
• Step 3: DNA or RNA PCR to quantify HIV viral load

Additional tests:

• Rapid HIV antibody test (<30 min) can be used as screening test. Confirmed by standard serology
• HIV antigen/antibody combo tests may be used to identify very recent infection during pregnancy or in mother following delivery
• HIV PCR is used to identify infection in infants

Question 4

What are the recommendations for Maternal HIV testing in pregnancy?

Answer 4

• HIV testing early in pregnancy is standard of care
• Repeat testing throughout pregnancy for women who are HIV-seronegative on initial testing but known to be at high risk
  
  • repeat test in beginning of 3rd trimester (ideally before 36 wk GA) and at delivery for women with unclear ongoing risk of acquiring HIV (IVDU, commercial sex work, frequent unprotected intercourse with multiple partners, HIV-negative woman of a serodiscordant couple)

Question 5

What do you do if HIV status of mom unknown at time of labour?

Answer 5

• should have rapid HIV testing at time of labour or delivery
  
  • if positive: intrapartum and infant postnatal antiretroviral proph should be started (pending results of confirmatory HIV antibody test)
  • Consult peds ID urgently for preferred antiretroviral regimen

Question 6

What do you do if HIV testing not done for mom during labour?

Answer 6

• should undergo rapid HIV antibody testing in immediate postpartum period
  
  • if mom not available or refuses testing, newborn must undergo rapid HIV antibody testing
  • Child protection may need to be notified if parent refuses for infant to be tested
• If rapid HIV antibody unavailable and concern that mother at high risk for HIV infection, consider starting newborn ARV prophylaxis pending test results

Question 7

What is the time frame for infant HIV ARV proph to be initiated?

Answer 7

• 72 hours post-delivery

* defer breastfeeding until confirmatory HIV antibody test result available and negative

Question 8

What do you do for HIV-seronegative women in whom acute HIV infection is suspected during pregnancy, intrapartum, or while breastfeeding?

Answer 8

do virologic test (ex HIV RNA PCR or antigen test) ASAP because antibody tests may be negative early in HIV infection

Question 9

Which pediatric patients is HIV antibody testing routinely recommended for? (outside newborn period)

Answer 9

• HIV antibody testing recommended for infants in foster care and for adoptees whose birth mother’s HIV infection status is not known