Infections in Pregnancy Flashcards
What investigations should be ordered for an asymptomatic pregnant woman newly diagnosed with hepatitis B? What specialist referrals should be initiated?
Investigations: HBeAg, anti-HBe, IgM to hepatitis B core antigen, viral load, ALT, GGT, albumin, bilirubin, INR, liver US, test for co-infections (hepatitis A, C, delta & HIV) & other causes of liver disease
Referrals: adult hepatology or infectious diseases (to manage maternal disease), MFM or peds (to assess & manage risk of perinatal transmission)
How would you counsel a woman who is on tenofovir for hepatitis B infection who becomes pregnant?
Continue using tenofovir - will continue to benefit her health, abrupt discontinuation may lead to disease flaring in pregnancy or postpartum, there is good safety data in pregnancy (category B), reduces perinatal transmission in women with elevated viral loads
What are the two most common routes of hepatitis B transmission in Canada? Worldwide?
In Canada - sex, IV drug use
Worldwide - vertical, horizontal (child-to-child)
How would you counsel a woman with hepatitis B who wishes to breastfeed?
Breastfeeding has not been shown to increase transmission of hepatitis B (whether or not the infant receives post-exposure prophylaxis & vaccination)
Take care not to expose the infant to blood from cracked nipples
Continue antiviral treatment if warranted for maternal health
How would you recommend women in the following scenarios begin trying to conceive?
- HIV positive woman with negative male partner
- HIV positive woman in same-sex relationship
- HIV negative woman with positive male partner
- HIV positive woman with positive male partner
- Home insemination with partner’s sperm
- IUI with negative donor sperm (preferred to home insemination because sperm is expensive & pregnancy rates are higher w/ IUI)
- IUI with washed sperm
- Natural conception, provided both partners are on cART and have fully suppressed viral loads
(UNAIDS statement: cannot transmit HIV through sexual activity if adherent to cART under medical supervision, viral load undetectable x6 months, no other STIs present).
Which women with HIV should be offered primary cesarean section? What medication should be given primary to cesarean? Should the same medication be offered to women planning vaginal delivery?
Women not on optimal antiretroviral therapy - no therapy, monotherapy only, or incompletely suppressed viral load ( > 1000)
CS at 38 weeks as benefits of CS are only for elective, not emergency CS
IV zidovudine for all women - regardless of mode of delivery, current medication regimen, or viral load
(Can also consider a single oral dose of nevirapine for women who did not receive antenatal antiretrovirals)
Your patient living with HIV has hyperemesis gravidarum and cannot tolerate her antiretrovirals. She is on three different medications. How would you advise her?
Aggressively treat HG
Stop all three medications at once, & restart all at once when she is able to tolerate them again (monotherapy increases the risk of developing resistance)
Which uterotonic is to be avoided in women with HIV?
Ergotamine (specifically to be avoided in women on protease inhibitors due to risk of excessive vasoconstriction)
Note bromocriptine & cabergoline are ergot derivatives so unfortunately cannot be offered pp to women with HIV who will not be breastfeeding
How is parvovirus spread?
Respiratory secretions, hand-to-mouth contact, transplacentally, through contaminated blood products
What is the most common presentation of parvovirus in a pregnant woman?
Asymptomatic in up to 70%
(Other potential presentations: arthropathy in up to 50%, fever & headache, anemia & transient aplastic crisis, myocarditis)
How would you counsel a woman about the risk of parvovirus infection in pregnancy? How would you manage an exposed pregnancy?
Risk of transmission to fetus is < 35%, most fetuses have disease resolution with no adverse outcomes (< 0.5% fetal loss after 20 weeks), no association with congenital anomalies, incidence of hydrops is low (< 3%), no apparent increase in long-term adverse neonatal outcomes in absence of hydrops
Management: parvo serology (IgM & IgG), if recent infection diagnosed do serial US including MCA PSV for 8-12 weeks after infection, recommend fetal movement counts (hydropic fetuses move less), refer to MFM for consideration of cordocentesis & transfusion versus delivery if fetus develops hydrops
What are the three most common routes of exposure to toxoplasmosis?
Vertical transmission
Exposure to infected cat feces
Ingestion of raw or undercooked meats (60% of Inuit women exposed due to consumption of undercooked seal meat)
How might you diagnosis an acute toxoplasmosis infection in a pregnant woman?
Serology x2 - if both IgG & IgM positive (IgM may persist for years so is unreliable for dx of acute infection, instead repeat testing in 2-3 weeks to see if IgG levels rise fourfold)
Amniocentesis (PCR) - only perform if > 18 weeks GA, > 4 weeks from suspected exposure
How would you counsel a woman who gets shingles in pregnancy?
Shingles = VZV reactivation (dormant in sensory nerve root ganglia)
Not associated with viremia or any fetal consequences
List three manifestations of congenital varicella syndromes.
Chorioretinitis
Cerebral cortical atrophy
Hydronephrosis
Cutaneous and bony leg defects ("chicken legs")
Partial limb reductionExplain the immunologic reason why neonatal varicella can be so virulent.
Peripartum maternal infection = mother does not produce IgG prior to delivery & therefore fetus does not get trans-placental antibodies/passive immunity (if mother is given VZIG, neonatal complications are reduced)
How would you treat a susceptible pregnant woman exposed to varicella?
VZIG
Oral antivirals if infection is confirmed
IV antivirals if seriously ill
What is the most common cause of intrauterine infection?
CMV (also leading cause of mental retardation, sensorineural deafness)
What further testing would you recommend for a pregnant woman who contracts CMV? How would you counsel her about the prognostic value of the test?
Amniocentesis: gold standard for diagnosis of fetal infection
Positive test doesn’t tell you what sequelae (if any) the fetus will exhibit - significance of viral load unclear, & majority of infected fetuses will be asymptomatic
(Consider US q2-4 weeks, fetal MRI if brain abnormalities seen)
What treatments exist for congenital CMV?
None - TOP is only management option
List five obstetrical complications associated with bacterial vaginosis infection.
Preterm labour & delivery PPROM SA Chorioamnionitis Postpartum endometritis Surgical wound infection
Name three organisms implicated in bacterial vaginosis.
Gardnerella Mobiluncus Bacteroides Prevotella Mycoplasma
How would you clinically diagnose bacterial vaginosis?
3 of 4:
- Adherent, homogeneous discharge
- pH > 4.5
- Clue cells on wet mount (epithelial cells with borders obscured by bacteria)
- Whiff test (amine odour after addition KOH)
Why are topical agents not recommended for treatment of bacterial vaginosis in pregnancy?
Topical agents don’t effectively reduce the risk of PTB (although they effectively eradicate the infection)
What is the recommended mode of delivery for the following women:
- A woman who has a primary infection with genital HSV in the third trimester of pregnancy
- A woman who has her first clinically recognized but non-primary infection in the third trimester
(How might these two scenarios be distinguished from each other?)
Distinguish with serology - patient with first clinical non-primary episode will have antibodies to HSV
Both patients should be delivered by CS (any woman with a genital lesion or prodrome should be delivered with CS)
What is the most common sequela of rubella infection in the third trimester?
IUGR (after 20 weeks no risk of congenital rubella syndrome)
How would you counsel a previously vaccinated pregnant woman who has become reinfected with rubella?
Congenital rubella syndrome is possible but unlikely (highest risk for CRS is 8% in the first trimester)
How would you counsel a woman who inadvertently received the rubella vaccine in the first trimester of pregnancy?
No reported CRS with vaccination in early pregnancy, would not recommend TOP for this reason
What is the factor with the strongest effect on vertical transmission of hepatitis C?
Coinfection with HIV
What is the effect of pregnancy on the natural history of hepatitis C? What treatment can you offer a pregnant woman with hepatitis C to reduce vertical transmission?
No effect on disease course (& disease has no effect on obstetric/perinatal complications in the absence of advanced liver disease)
No treatment to reduce vertical transmission
List four reasons why a pregnant woman should be screened for hepatitis C.
IVDU Hemodialysis patient Persistently elevated ALT Received transfusion or organ donation from hepatitis C positive individual (or significant exposure to that individual's blood), or prior to 1990s In a correctional facility Child of hepatitis C positive mother and reason to believe vertical transmission may have taken place HIV positive Tattoos (especially prison tattoos)
Put the following events in order: Exposure to hepatitis C Elevated ALT Clinically overt hepatitis Appearance of HCV RNA in blood Appearance of anti-HCV
Exposure RNA ALT Anti-HCV Overt hepatitis
