Download Zika virus infection: Evaluation of pregnant women and infants

Zika virus infection:
Evaluation of pregnant
women and fetuses
Laleh Eslamian MD, Perinatologist
Professor of Obstetrics & Gynecology
TUMS
There is no evidence to suggest:
O Pregnant women are more susceptible to Zika
virus infection.
O Transmission of Zika virus infection through
breastfeeding.
O Pregnant women experience more severe
disease than nonpregnant women, however,
viremia may persist longer in pregnant women.
Congenital infection
Zika virus infection in all trimesters has been associated with fetal
abnormalities.
O
Microcephaly
O
Fetal loss and stillbirth
O
Ocular abnormalities: include focal pigment mottling, chorioretinal atrophy, and optic nerve
abnormalities
O
Other CNS abnormalities (eg, ventriculomegaly, global hypogyria, hydranencephaly)
O
Hydrops fetalis
O
Fetal growth restriction
O In areas with no known mosquito-borne Zika
virus transmission, healthcare providers
should determine whether the pregnant
woman is at risk because of her travel or
sexual history.
O Women who is @ risk or who live in an area
with known Zika virus transmission should
be asked about symptoms consistent with
Zika virus infection.
Women with no exposure to
Zika virus
O For pregnant women with no relevant
epidemiologic exposure, laboratory testing
or fetal screening for Zika virus infection is
not indicated.
Women with symptoms consistent
with possible Zika virus infection
O Should have both lab testing and ultrasound
exam within 2 weeks of epidemiologic exposure.
O For patients presenting <7 days after onset of
symptoms, check serum Zika virus RNA (RTPCR). A positive test is diagnostic of infection.
O If the RT-PCR is negative and the patient is ≥4
days after the onset of symptoms, check Zika
virus IgM and neutralizing antibody titers. A
positive test is presumptive of infection.
Asymptomatic women with possible
but not ongoing exposure to Zika virus
O Should have both laboratory testing and
ultrasound examination.
O Should have Zika virus IgM and neutralizing
antibody titers checked 2 to 12 weeks
following exposure.
O A negative IgM result 2 to 12 weeks
following exposure suggests absence of a
recent infection.
Asymptomatic women with ongoing
risk for Zika virus infection
O Should have both laboratory testing and
ultrasound examination.
O Zika virus IgM and neutralizing antibody titers
are warranted at the initiation of prenatal care. A
positive test is diagnostic of infection.
O If the initial test is negative and performed in the
1st or early 2nd trimester, repeat testing at 18 to
20 weeks.
O A negative IgM result 2 to 12 weeks following
exposure suggests absence of a recent
infection.
EVALUATION OF FETAL
LOSS AND STILLBIRTH
O Fetal tissue testing is warranted for fetal losses
in women with history of Zika exposure, together
with either symptoms consistent with Zika virus
infection during or within two weeks of exposure
or findings of fetal microcephaly.
O Zika virus RT-PCR and histopathologic
examination with immunohistochemical staining
should be performed on fetal tissues, including
the umbilical cord and placenta.
SCREENING FOR FETAL
INFECTION
O Ultrasound is the major modality used to
screen for fetal Zika virus infection, but MRI
is more sensitive.
O Ultrasound findings associated with fetal
Zika virus infection may be detected as early
as 18 to 20 weeks gestation in some cases.
O The two major ultrasound findings
suggestive of congenital Zika virus infection
are: 1) microcephaly
2) intracranial calcification
O The International Society of Ultrasound in
Obstetrics and Gynecology (ISUOG) interim
guidance on ultrasound for Zika virus infection in
pregnancy recommends a baseline ultrasound
examination for:
1) women with Zika virus exposure and
symptoms
2) positive serology or proven Zika virus infection
3) or exposure and/or symptoms without
positive serology results.
O If the baseline examination is normal, the
ISUOG recommends serial ultrasound
examinations every 4-6 weeks, if possible.
O If the baseline examination is abnormal,
referral to a specialist for neurosonography
of the fetal brain is recommended.
O In the absence of microcephaly, if the head
circumference is small or not enlarging
appropriately, MRI may detect abnormalities
not visible on ultrasound and may be useful.
Amniocentesis
O Zika virus reverse-transcription polymerase
chain reaction (RT-PCR) positivity in amniotic
fluid is diagnostic of fetal viral exposure but not
predictive of outcome.
O The indications for diagnostic amniocentesis,
the appropriate gestational age for testing, and
the interpretation of the test are uncertain.
O Decisions regarding amniocentesis should be
tailored to individual clinical circumstances.
Amniocentesis is offered to women with either of
the following:
O Fetal microcephaly (3SD below the mean for
gestational age), intracranial calcifications,
and/or ventriculomegaly, regardless of
maternal laboratory test results for Zika
virus infection.
O Positive or inconclusive maternal laboratory
test results for Zika virus infection.
Timing of amniocentesis
O For women with characteristic sonographic findings of
fetal Zika virus infection, amniocentesis upon diagnosis
and as early as 15 to 16 weeks is reasonable. But not
<15 weeks because of an increased risk of pregnancy
loss.
O For women with positive or inconclusive Zika virus test
results and a normal-appearing fetus, the optimal timing
for performance of amniocentesis is uncertain. 6-8
weeks after maternal infection is suggested.
O If amniocentesis is performed 6-8 weeks after maternal
infection and false-negative results are suspected, a
repeat amniocentesis later in gestation may be
considered.
Interpretation of
amniocentesis result
O The sensitivity and specificity of Zika virus RT-PCR testing of
amniotic fluid for diagnosis of congenital infection are not
known and likely depend on timing of amniocentesis after
onset of maternal infection.
O A positive RT-PCR result on amniotic fluid should be
considered suggestive of intrauterine infection.
O If the test was performed because of maternal laboratory
findings or viral exposure and the fetus appears normal, it is
unknown whether a positive amniotic fluid RT-PCR result is
predictive of a subsequent fetal abnormality and, if so, what
proportion of infants will have abnormalities.
O If the RT-PCR is negative and the fetus is abnormal, evaluation
for other causes of the fetal abnormalities should be
considered.
Antepartum fetal monitoring
O Infected fetuses are at risk for stillbirth.
O If antenatal testing is performed (eg,
nonstress test, biophysical profile) and
results are abnormal, early delivery may be
appropriate, depending on the clinical
scenario.
NEWBORN EVALUATION
O All newborns should undergo thorough evaluation
within 24 hours of birth.
O The occipitofrontal circumference should be
measured.
O Diagnostic criteria for congenital infection —the
presence of Zika virus RNA in any of the samples
collected, including amniotic fluid, placenta, umbilical
cord, newborn serum, or newborn CSF. In addition,
congenital infection may be established by the
presence of Zika virus IgM antibodies in newborn
serum or CSF, with confirmatory neutralizing antibody
titers that are ≥4-fold higher than dengue virus
neutralizing antibody titers.
EVALUATION OF WOMEN AND NEWBORNS
WITH PERIPARTUM ZIKA VIRUS EXPOSURE
O Maternal-fetal transmission of Zika virus can
occur during labor and delivery.
O There are no reports of Zika virus infection
acquired by an infant at the time of delivery
leading to microcephaly.
O Maternal and newborn laboratory testing is
indicated during the first two weeks of life if the
mother had relevant epidemiologic exposure
within two weeks of delivery and had ≥2 of the
following manifestations of Zika virus infection:
rash, conjunctivitis, arthralgia, or fever
Planning pregnancy
O There is no evidence that women who have had a
prior Zika virus infection are at risk of birth defects in
future pregnancies.
O CDC recommends that:
1) women who have had a Zika virus infection should
wait at least eight weeks after symptom onset before
attempting conception.
2) men with symptomatic Zika virus infection
(confirmed or suspected) wait at least six months before
having unprotected sex.
3) asymptomatic men with Zika virus exposure (via
travel to mosquito transmission areas or sexual contact)
wait at least eight weeks before unprotected sex.
Thank You