Wednesday, 24 February 2010

HIV in Pregnancy

Clinical features of HIV

1-primary infection/seroconversion
Asymptomatic or
Accompanied by fever,fatigue,lymphadenopathy or rash

2-Latent phase

3.Symtomatic disease
Opportunistic infections-Ex.pneumocystis pneumonia
Secondary neoplasm-Ex.Kaposi’s sarcoma


Investigation

  1. HIV antibody test-antibody to part of viral membrane/envelope
  2. Another test is Polymerase chain reaction(PCR) for viral DNA/viral RNA
  3. CD4 count reflect the current degree of immunosuppression
  4. HIV-RNA level is the main predictor of disease progression.

HIV1 vs HIV 2
Less virulent clinical disease
Less likely to be vertically transmitted

Mother to child transmission
Non breast feeding women in Europe 15-20%
Breast feeding mothers in Africa 25-40%
Breast feeding is associated with 2 fold increase in transmission.


Prevention
Maternal child transmission is prevented by
  • Antenatal HIV screening
  • Antiretroviral therapy
  • Elective Caesarean section
  • Avoiding breast feeding

Reduced from 25-30% to less than 2 %

Effect of pregnancy on HIV
CD4 counts fall during pregnancy but return to pre pregnancy levels post partum.
No increased risk of accelerated immunosuppression.

Effect of HIV in pregnancy
  • Fertility-reduced (may be due to other STD)
  • Increased spontaneus abortion
  • Preterm birth-may be due to HIV/may be due to confounding variable
  • Small for gestational age-statistically significant but modest effect on fetal growth
Antenatal management
  • Screening for HIV should be offered early in pregnancy because appropriate antenatal interventions can reduce maternal-to-child transmission of HIV infection.
  • positive HIV antibody test result should be given to the woman in person by an appropriately trained health professional.
multidisciplinary team

HIV positive patients should be managed by a multidisciplinary team.
  • HIV physician
  • an Obstetrician
  • a Midwife
  • a Paediatrician
  • a Psychiatric team
  • support groups
Confidentiality
Confidentiality is important.
Information may be disclosed to a known sexual contact of the woman ,where she can’t be persuaded to do so.Link


Booking visit
Additional tests requested are
  • Lymphocyte subsets
  • Quantitaive RNA PCR measurement of viral load
  • Hepatitis B & C
  • Cervical & vaginal swaps to check for STDs,Bacterial vaginosis & Group B streptococcus.
  • CD4 count should be tested every trimester or more frequently if maternal viral load is high.





Antiretroviral therapy
2 reasons
1. prevention of mother-to-child transmission (therapy usually discontinued at, or soon after, delivery)
2.secondly for treatment of the mother to prevent maternal disease progression (therapy continued indefinitely after delivery)

  • anti-retroviral therapy is recommended for all HIV positive women during pregnancy and at delivery to prevent MTCT.
  • The optimal regimen is determined by an HIV physician on a case-by-case basis.
  • The decision to start,modify or stop anti-retroviral therapy
– should be undertaken by an HIV physician
– in close liaison with other health professionals
obstetrician
paediatrician.
  • Antiretroviral therapy
Women who are not on HIV treatment for their own health need anti-retroviral therapy to prevent mother-to-child transmission.

Anti-retroviral therapy is usually started between 28 and 32 weeks of gestation and should be continued intrapartum.


A maternal sample for plasma viral load is taken at delivery.


Maternal anti-retroviral therapy is usually stopped soon after delivery but the precise time of discontinuation should be discussed with the HIV physician.

Zidovudine is usually administered orally to the neonate for four to six weeks.


Antiretroviral therapy


Timing
– Antenatal(consider possibility of preterm Ex.Twins)
– Intrapartum
– Neonatal period(4-6 weeks)
Choice of antiretroviral therapy & Timing is decided by HIV physician.


Plasma viral load & CD4 counts regularly monitored.


Timing of prophylaxis

When to start prophylaxis in women who doesn’t require treatment for their disease?




ACTG076(AIDS clinical trial group ) recruited from 14-36 weeks & median gestation was 26 weeks.



If shorter exposure
• Less chance of possible long term complications
• Less chance of selecting zidovudine resistant species
– BUT risk of inadequate therapy incase of preterm labour

• Antiretroviral therapy......



Patients on antiretroviral therapy should be monitored for toxicity
• full blood count
• urea and electrolytes
• liver function tests
• Lactate
• blood glucose
• Patients should also have detail ultrasound scan to detect foetal anomalies.


Drug toxicity
• 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 should be sought.
• Lactic acidosis
– is a recognised complication of certain HAART regimens.
• presenting symptoms
• often nonspecific
• include
– gastrointestinal disturbance
– fatigue
– fever
– breathlessness.

Types of HIV drugs
• Reverse transcriptase inhibitors
– Nucleoside reverse transcriptase inhibitors
– Non nucleoside reverse transcriptase inhibitors
• Protease inhibitors
• Entry inhibitors
• Integrase inhibitors
• Maturation and assembly inhibitors
• Other viral proteins
– More information at aidsmap

Drug safety in pregnancy
• Category B (animal studies fail to show risk to fetus) ddI ,saquinavir,ritonavir,nelfinavir
• Category C(animal studies have either not been done or have shown abnormalities Indinavir,nevirapine
• Efavirenz has shown teratogenic potential
• Mitochonrial toxicity is another concern-Review

Prophylaxis of Pneumocystis carinii

• PCP prophylaxis is usually administered when the CD4 T-lymphocyte count is below 200 106/l.
• The first line treatment is cotrimoxazole(a folate antagonist).
• Folic acid 5 mg should also be given
• Nebulised pentamidine is another alternative.


Screening for genital infections



All pregnant women who are HIV positive should be screened genital infections.



When to do ?
This should be done as early as possible in pregnancy
• repeated at around 28 weeks.
• Any infection detected should be treated according to UK national guidelines.


Antenatal care
• Screening for Down syndrome and fetal anomalies should be offered.
• A detailed ultrasound scan for fetal anomalies is important after first-trimester exposure to HAART and folate antagonists used for prophylaxis against PCP.
• invasive prenatal diagnosis
• The risk of mother-to-child transmission with chorionic villus sampling or second-trimester amniocentesis are hasn’t been estabilished.
• If invasive prenatal diagnosis is contemplated, the advice of the fetal medicine specialist and HIV physician should be seeked and prophylaxis with HAART considered.

Prevention of MTCT
• 2 choices of antiretroviral therapy
– Single agent-Zidovudine
– START(short term antiretroviral therapy)- HAART for short duration in pregnancy and continued intrapartum

Zidovudine Vs START

Disadvantage of Zidovudine -

may allow the emergence of resistant virus


START


advantgage-

maternal plasma viraemia is more likely to be suppressed to undetectable levels


Disadvantage-

exposure of the mother and fetus to larger numbers of potentially toxic drugs




Advanced HIV
• likely to have symptomatic HIV infection and
– a falling or low CD4 T-lymphocyte count (less than 350 106/l)
– and/or a high viral load (greater than 10 000–20 000 copies/ml).
• advanced HIV
• These women 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.
• advanced HIV
• Women who conceive while taking HAART should continue their HAART regimen if it is effectively suppressing plasma viraemia.
• For women whose regimen is not suppressing viraemia, a change in therapy after the first trimester may be indicated.

Mode of delivery
• Elective Caesarean section is beneficial
– HIV positive women who are not taking HAART during pregnancy
– for women with a detectable plasma viral load
• Value of elective caesarean section is uncertain
– in women taking HAART who have an undetectable plasma viral load at the time of delivery.


LSCS in HIV women

• A zidovudine infusion
– should be started four hours before beginning the caesarean section
– Should continue until the umbilical cord has been clamped.
• A maternal sample for plasma viral load should be taken at delivery.
• The cord should be clamped as early as possible after delivery and the baby should be bathed immediately after the birth.

LSCS in HIV women....
• a technique of ‘bloodless’ caesarean section may further reduce the risk of mother-tochild transmission.
– opening the uterus with a staple gun,which simultaneously cuts and giveshaemostasis.
• Casarean section
• This should be sheduled at 38 weeks to reduce the risk of spontaneus labour or membrane rupture.
• Contamination of the baby with maternal blood should be avoided
– Secure the bleeding points
– Allowing the membrane to be present along uterine incision prior to the rapid delivery of baby
• Cord clamped as soon as possible

Casarean section
• Drainage should be used sparingly and they should be used to closed suction system
• Universal precautions :gloves, aprons & face protection should be employed.




Labour in HIV woman
• Women who opt for a planned vaginal delivery should have their membranes left intact for as long as possible.
• Use of fetal scalp electrodes and fetal blood sampling should be avoided.
• Women should continue their HAART regimen throughout labour .
• If an intravenous infusion of zidovudine is required it should be commenced at the onset of labour and continued until the umbilical cord has been clamped.
• A maternal sample for plasma viral load should be taken at delivery.
• The cord should be clamped as early as possible after delivery and the baby should be bathed immediately after the birth.
• HIV infection per se is not an indication for continuous electronic fetal monitoring
• Vaginal delivery
• Forceps preferred to Vacuum
• Remove maternal blood stain with alcohol wipe prior to Vitamin K injection
• Universal precautions :gloves, aprons & face protection should be employed.






Women scheduled for Emergency caesarean section presents in early labour
– Studies have shown no benefit with non elective caesarean
– In case of
• Early stages of labour
• Patient presenting immediately after SROM
• Probability of prolonged labour
– LSCS still may be protective
• If quick delivery is likely one could wait for vaginal delivery.

SROM in HIV
• SROM-spontaneus rupture of Membranes
– ruptured membranes for more than four hours were associated with double the risk of HIV transmission.
– These studies also demonstrated a 2% incremental increase in transmission risk for every hour of rupturedmembranes up to 24 hours.
– The relevance of these studies for women taking HAART who have undetectable viral loads is uncertain.

PPROM in HIV
• PPROM-preterm prelabour rupture of membranes
– If there is preterm rupture of membranes, with or without labour, the risk of HIV transmission should be set against the risk of preterm delivery.
– Preterm infants are more likely to be infected with HIV.
– There is no known contraindication to the use of short-term steroids to promote fetal lung maturation.


Postpartum
• In UK women with HIV advised not to breast feed
• Neonate infections.
– PCR is done as maternal antibodies cross the placenta
– Typically, tests are carried out at birth, then at three weeks, six weeks and six months.
– definitive test is the HIV antibody test: a negative result at 18 months of age confirms that the child is uninfected.


Management of the neonate

• All infants born to women who are HIV positive should be treated with anti-retroviral therapy from birth.
• Usually treatment is discontinued after four to six weeks

IVF pregnancy in HIV patients
• This is ethically acceptable
– Life expectancy of couple is improved HAART
– Vertical transmission can be reduced to less than 2%

• Pre pregnancy counselling should be done.
• IVF pregnancy in HIV patients.

If Male HIV Negative-

artificial insemination at the time of ovulation, and quills, syringes and Gallipots may be provided.


If Female HIV negative-

‘Sperm washing’-spermatozoa are separated from surrounding HIV-infected seminal plasma by a sperm swim-up technique




Needle stick injury
• In case of needle stick injury post exposure prophylaxis has to be started with in 1-2 hours


More information
HIV Association



Sources
Greentop guideline
• Nelson-Piercy C. Handbook of obstetric medicine. Taylor & Francis; 2002.
• Swiet MD. Medical disorders in obstetric practice. Wiley-Blackwell; 2002.





No comments:

Post a Comment

Your comments are welcome.