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Questions and Answers
What is the strongest predictor of perinatal HIV infection?
What is the strongest predictor of perinatal HIV infection?
Maternal plasma HIV RNA level.
Name one obstetric risk factor that increases the likelihood of HIV transmission.
Name one obstetric risk factor that increases the likelihood of HIV transmission.
Vaginal delivery.
What is the recommended treatment for mothers with low CD4 counts and high viral load?
What is the recommended treatment for mothers with low CD4 counts and high viral load?
Combination ART treatment is recommended.
What is the purpose of zidovudine chemoprophylaxis during pregnancy?
What is the purpose of zidovudine chemoprophylaxis during pregnancy?
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When should all pregnant women commence ART according to the guidelines?
When should all pregnant women commence ART according to the guidelines?
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What is the recommended delivery method for women with a viral load of 400 HIV RNA copies/mL at 36 weeks?
What is the recommended delivery method for women with a viral load of 400 HIV RNA copies/mL at 36 weeks?
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What is the recommended duration for neonatal post-exposure prophylaxis after birth?
What is the recommended duration for neonatal post-exposure prophylaxis after birth?
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What medical intervention is advised to prevent breastfeeding in HIV-positive mothers?
What medical intervention is advised to prevent breastfeeding in HIV-positive mothers?
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What is the overall risk of transmission of CMV to the fetus following primary maternal infection?
What is the overall risk of transmission of CMV to the fetus following primary maternal infection?
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During which trimester of pregnancy is the risk of CMV transmission to the fetus greatest?
During which trimester of pregnancy is the risk of CMV transmission to the fetus greatest?
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What percentage of infants with congenital CMV will show signs and symptoms at birth?
What percentage of infants with congenital CMV will show signs and symptoms at birth?
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How is a secondary maternal CMV infection diagnosed?
How is a secondary maternal CMV infection diagnosed?
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What is the sensitivity of PCR testing for CMV in amniotic fluid performed after 21 weeks of gestation?
What is the sensitivity of PCR testing for CMV in amniotic fluid performed after 21 weeks of gestation?
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What preventive measures are recommended for pregnant women to reduce the incidence of CMV infection?
What preventive measures are recommended for pregnant women to reduce the incidence of CMV infection?
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What are the developmental abnormalities associated with congenital CMV infection?
What are the developmental abnormalities associated with congenital CMV infection?
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What is not recommended in the routine clinical care of pregnant women with CMV infection?
What is not recommended in the routine clinical care of pregnant women with CMV infection?
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What is the prevalence of HBV infection among antenatal women in the UK?
What is the prevalence of HBV infection among antenatal women in the UK?
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Explain the main route of transmission for HBV.
Explain the main route of transmission for HBV.
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What percentage of HBeAg positive mothers is likely to transmit HBV to their baby?
What percentage of HBeAg positive mothers is likely to transmit HBV to their baby?
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What is the role of HBIG in the management of babies born to highly infectious HBV mothers?
What is the role of HBIG in the management of babies born to highly infectious HBV mothers?
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How does maternal rubella infection during early pregnancy affect infant outcomes?
How does maternal rubella infection during early pregnancy affect infant outcomes?
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What are the incubation period and infectious period of rubella?
What are the incubation period and infectious period of rubella?
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Discuss the importance of vaccination in preventing rubella.
Discuss the importance of vaccination in preventing rubella.
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What is the primary virus responsible for rubella and how is it transmitted?
What is the primary virus responsible for rubella and how is it transmitted?
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What factors influence the risk of vertical transmission of parvovirus B19 during pregnancy?
What factors influence the risk of vertical transmission of parvovirus B19 during pregnancy?
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How can fetal parvovirus infection be definitively diagnosed?
How can fetal parvovirus infection be definitively diagnosed?
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What is the role of Doppler assessment in managing pregnancies affected by parvovirus B19?
What is the role of Doppler assessment in managing pregnancies affected by parvovirus B19?
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What are the implications of hydrops fetalis resulting from parvovirus infection during pregnancy?
What are the implications of hydrops fetalis resulting from parvovirus infection during pregnancy?
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What percentage of fetuses is expected to recover following a transfusion if hydrops or severe anaemia is treated?
What percentage of fetuses is expected to recover following a transfusion if hydrops or severe anaemia is treated?
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What are the only options available following a prenatal diagnosis of CMV infection?
What are the only options available following a prenatal diagnosis of CMV infection?
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How might fetal MRI improve prognostic evaluation in cases of CMV infection?
How might fetal MRI improve prognostic evaluation in cases of CMV infection?
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What main factor increases the risk of neonatal herpes in relation to the timing of a primary infection?
What main factor increases the risk of neonatal herpes in relation to the timing of a primary infection?
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What are the recommendations for women presenting with their first episode of genital herpes in the third trimester?
What are the recommendations for women presenting with their first episode of genital herpes in the third trimester?
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What is the role of aciclovir in managing genital herpes during pregnancy?
What is the role of aciclovir in managing genital herpes during pregnancy?
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What should be done to all lesions identified in cases of suspected HSV infection?
What should be done to all lesions identified in cases of suspected HSV infection?
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What is the significance of maternal immunity in relation to parvovirus B19 during pregnancy?
What is the significance of maternal immunity in relation to parvovirus B19 during pregnancy?
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Why is a caesarean section recommended for women developing first-episode genital herpes in the third trimester?
Why is a caesarean section recommended for women developing first-episode genital herpes in the third trimester?
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Study Notes
Perinatal Infections
-
HIV
- Strongest predictor of perinatal transmission: Maternal plasma HIV RNA level
-
Other predictors of perinatal transmission:
- Advanced clinical disease in the mother
- Acute HIV infection during pregnancy
- Low CD4+ counts
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Obstetric risk factors:
- Vaginal delivery
- Prolonged rupture of membranes
- Chorioamnionitis
- Invasive obstetric procedures
-
Diagnosis:
- Primary screen-positive results are confirmed by at least two specific HIV assays
- CD4 count and viral load provide information about the patient's status and medication needs
-
Management:
- Multidisciplinary team (MDT) advice on managing the infection and reducing vertical and sexual transmission
- Antiretroviral therapy (ART) to reduce viral load below detectable levels
- Caesarean section for high viral load or to prevent vertical transmission
- ART is initiated by week 24 of pregnancy
- Vaginal delivery is recommended at 36 weeks if viral load is less than 50 HIV RNA copies/mL
- Elective caesarean section is recommended at 36 weeks if viral load is 400 HIV RNA copies/mL
- Intrapartum IV zidovudine and neonatal oral zidovudine for 4 weeks are used for post-exposure prophylaxis
- Breastfeeding: Avoid breastfeeding
Hepatitis B
- Virus: Hepatitis B virus (HBV)
- Prevalence in antenatal women in the UK: Around 0.14%
- Transmission: Parenteral exposure to infected blood or body fluids; vaginal or anal intercourse; blood-to-blood contact (sharing needles, needlestick injuries); perinatal transmission from mother to child
- Diagnosis: Presence of HBsAg in the serum
- Perinatal transmission: Occurs at or near birth; transplacental transmission; amniocentesis in HBsAg-positive mothers
- Risk of chronic infection in neonates: Greater than 90%
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Management:
- Referral to a specialist (hepatologist, gastroenterologist, or infectious disease specialist) within 6 weeks of a positive result
- Complete course of hepatitis B vaccine for all babies born to HBsAg-positive mothers
- Hepatitis B immunoglobulin (HBIG) and vaccination for babies born to highly infectious mothers, preferably within 24 hours of delivery
Rubella
- Teratogenic effects: One of the most teratogenic infections known
- Virus: Togavirus
- Transmission: Droplet transmission
- Infection rate: Nearly 80% of susceptible individuals become infected after exposure
- Replication and viremia: Occurs 5-7 days after exposure; usually results in placental and fetal infection
- Incubation period: 14-21 days; rash develops 14-17 days after exposure
- Infectious period: 1 week before symptoms to 4 days after the rash onset
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Maternal rubella infection in pregnancy:
- Can result in fetal loss or congenital rubella syndrome (CRS)
- Highest risk of damage (up to 90%) when infection occurs between 8 and 10 weeks of pregnancy
- Risk declines to 10-20% between 11 and 16 weeks of gestation
Cytomegalovirus (CMV)
- Vertical transmission: Mostly occurs through transplacental infection after primary or secondary infection; can also occur through contaminated genital tract secretions at delivery or breastfeeding
- Risk of transmission with primary maternal CMV infection: 30-40%
- Symptoms at birth: 12-18% of infants will have signs and symptoms
- Sequelae: Up to 25% will develop sequelae
- Risk of transmission with recurrent infection: 0.15-1%
- Risk of transmission by trimester: Highest in the third trimester (40-72%), lower in the first trimester (30%)
- Fetal damage: More serious the earlier in gestation transmission occurs
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Congenital CMV infection:
- Can cause a wide range of developmental abnormalities, including sensorineural hearing loss, microcephaly, motor defects, mental retardation, chorioretinitis, and dental defects
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Diagnosis:
- Primary maternal CMV infection: Specific IgG in the serum of a previously seronegative woman or specific IgM with low IgG avidity
- Secondary infection: Significant rise in IgG antibody titer, regardless of IgM presence and high IgG avidity
- Prenatal diagnosis: Testing amniotic fluid obtained by amniocentesis, with PCR sensitivity reaching 100% after 21 weeks of gestation and 7 weeks after presumed maternal infection
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Management:
- No specific therapies available for maternal or fetal CMV infection
- Antiviral medications are not recommended for routine clinical care of pregnant women
- Passive immunization with CMV-specific hyperimmune globulin is not recommended outside research protocols
- Education of susceptible pregnant women can reduce infection incidence
- Preventive measures like handwashing and minimizing exposure from high-risk areas are recommended
- Invasive testing can be offered to identify infected fetuses when a recent primary infection is diagnosed
- Parents should be informed about the risk of fetal infection (30-40%) and development of sequelae in infected fetuses (20-25%) after a prenatal diagnosis
- Options following prenatal diagnosis include termination of pregnancy or observation
- Fetal MRI may improve prognostic evaluation, especially when brain abnormalities are seen on ultrasound
Herpesvirus
- Neonatal herpes: Rare in the UK
- Viruses: Herpes simplex virus (HSV) types 1 and 2
- Transmission: Most often occurs by person-to-person contact; transplacental intrauterine infection (rare)
- Incubation period: 3-6 days
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Risk factors for neonatal HSV:
- Type of maternal infection (primary or recurrent)
- Presence of maternal antibodies
- Duration of rupture of membranes before delivery
- Use of fetal scalp electrodes
- Mode of delivery
- Greatest risk: Primary infection in the third trimester, particularly within 6 weeks of delivery
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Diagnosis:
- Patient history and clinical examination
- All lesions should be unroofed and cultured
- Specific HSV antibody testing (IgG to HSV-1 and HSV-2) is advisable for women presenting with a first episode of genital herpes in the third trimester, particularly within 6 weeks of delivery
- Referral to a genitourinary medicine physician for suspected genital herpes
-
Management:
- Aciclovir is not licensed for use in pregnancy
- Primary HSV infection in the third trimester: Management is expectant, vaginal delivery is anticipated, and daily suppressive aciclovir 400mg three times daily is given from 36 weeks of gestation until delivery
- Recurrent infection: Inform women of the low risk of neonatal herpes
- Caesarean section is recommended for all women developing first-episode genital herpes in the third trimester
Parvovirus B19
- Virus: Single-stranded DNA virus that prefers infecting rapidly dividing cells, particularly bone marrow erythroid progenitor cells
- Effect on fetus: Can lead to severe anemia
- Immunity: 50-70% of women of reproductive age are immune
- Infection rate in susceptible pregnant women: 1-3% will develop serological evidence of infection
- Risk factors: Mothers of preschool and school-age children and school teachers
- Transmission: Droplets from oral or nasal secretions, parenterally through blood or blood product transfusion, or vertically from mother to fetus
- Risk of intrauterine infection: Increases with gestational age, ranging from 15% before 16 weeks to 25-70% after 16 weeks
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Associations:
- Hydrops fetalis (non-immune), incidence 2.9%
- Spontaneous miscarriage and stillbirth
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Diagnosis:
- Recent parvovirus infection: Testing for parvovirus B19-specific IgG and IgM on the first serum obtained
- Fetal parvovirus infection: Considered if non-immune hydrops is detected on ultrasound; PCR to detect parvovirus B19 DNA in amniotic fluid or fetal blood samples
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Management:
- Monitor for fetal anemia using serial ultrasonography every 1-2 weeks for 12 weeks after infection
- Doppler assessment of peak systolic velocity in the fetal middle cerebral artery can predict fetal anemia
- Fetal blood sampling and transfusion if hydrops fetalis is present or severe fetal anemia is suspected
- If a transfusion is performed, 94% of fetuses recover within 6-12 weeks
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Description
This quiz covers the critical aspects of HIV as a perinatal infection, focusing on predictors of transmission, obstetric risk factors, diagnosis, and management strategies. Explore the role of maternal health and interventions that can reduce vertical transmission of HIV during pregnancy.
