Download Chickenpox in Pregnancy and Postnatal Period

Title of Guideline (must include the word “Guideline”
(not protocol, policy, procedure etc)
Guideline for the management of
Chickenpox in Pregnancy and the
postnatal period
Contact Name and Job Title (author)
Directorate & Speciality
Dr Corah Ohadike, ST7 Obstetrics and
Gynaecology
Obstetrics
Implementation date
March 2013
Version
Four
Supersedes
Three
Date of submission
March 2013
Date on which guideline must be reviewed (this should March 2018
be one to three years)
Explicit definition of patient group to which it applies
All pregnant women who have contact
(e.g. inclusion and exclusion criteria, diagnosis)
with or develop chickenpox in pregnancy
or the postnatal period
Abstract
This guideline describes the
management of chickenpox in
pregnancy and the postnatal period. It
also covers management of the exposed
neonate. Maternal, fetal and neonatal
risks are discussed.
Key Words
Chickenpox, Shingles, Varicella,
Pregnancy
VZIG, aciclovir
Statement of the evidence base of the guideline – has 2
the guideline been peer reviewed by colleagues?
Evidence base: (1-5)
1a
meta analysis of randomised controlled trials
1b
at least one randomised controlled trial
2a
at least one well-designed controlled study
without randomisation
2b
at least one other type of well-designed
quasi-experimental study
3
well –designed non-experimental descriptive
studies (ie comparative / correlation and case
studies)
4
expert committee reports or opinions and / or
clinical experiences of respected authorities
5
recommended best practise based on the
clinical experience of the guideline developer
Consultation Process
1
Consultant virologist- Professor Irving;
Neonatologist; Nottingham maternity
services guideline development group
Maternity services staff; General
practitioners; Accident and emergency
staff
Target audience
This guideline has been registered with the trust. However, clinical guidelines are
guidelines only. The interpretation and application of clinical guidelines will remain the
responsibility of the individual clinician. If in doubt contact a senior colleague or expert.
Caution is advised when using guidelines after the review date.
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Chicken Pox in Pregnancy
Introduction
Chickenpox, primary varicella zoster virus (VZV) infection, is
usually a mild, self-limiting disease of childhood. VZV is a DNA
virus of the herpes family. Transmission occurs by respiratory
droplets and direct personal contact with vesicular fluid (Tyring,
1992). In the UK, approximately 93% of adults have detectable
antibodies to varicella so most pregnant women are immune
(Nardone, et al. 2007). However, pregnant women who were born
and raised in tropical and sub-tropical areas are at increased risk
of varicella infection because a much lower proportion will have
had chickenpox in childhood (Talukder et al, 2007). In many
tropical countries 60% of the adult population is seropositive for
VZV (Lee, 1998). The morbidity and mortality is more severe in
adults than children. There are certain associated risk factors
which include: pre-existing lung disease, smoking and
immunocompromise. Pregnancy is also associated with more
severe disease (Immunisation Against Infectious Disease, DOH).
VZV infection incidence in pregnancy is quoted at 3 in 1000 or the
estimated occurrence of Varicella in pregnancy is 2000 cases per
year in England (Miller et al, 1993).
Primary infection and reactivation
VZV, a highly contagious virus, is transmitted in respiratory
droplets, usually from a patient with chickenpox and less frequently
from the rash of a patient with shingles. The primary infection
manifests after an incubation period of 10-21 days. It is
characterised by fever, malaise and a pruritic rash that develops
into crops of maculopapules, which become vesicular and then
crust over before healing. The disease is infectious 48 hours
before the rash appears and until the vesicles crust over (Tyring,
1992). Following recovery, the virus remains latent in the sensory
root ganglia but can reactivate later in life to cause a vesicular
erythematous rash in a dermatomal distribution called herpes
zoster or shingles (Shrim et al, 2012). Maternal shingles does not
appear to cause fetal problems (Enders and Miller, 1994).
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Maternal, Fetal and Neonatal Risks of Varicella in Pregnancy
Maternal risks
In susceptible pregnant women, chickenpox causes more severe
disease. Varicella pneumonia occurs in 9% of cases (Heuchan and
Isaacs, 2001; Mohsen and McKendrick, 2003). Risk factors include
infection after 20 weeks gestation as T-cell function starts to
decline, past history of smoking, pre-existing chronic lung disease,
immunocompromise, and the presence of greater than 100 lesions
(Harger et al, 2002). Mortality in pregnant women is increased,
compared with non pregnant adults, primarily due to respiratory
disease. Mortality rates are highest from the second trimester to
beginning of the third trimester, 7 out of 9 deaths that occurred in
England in 1985-1998 were between 27-32 weeks. (Enders and
Miller, 2000).
Fetal risks
The risk of damage to fetus and newborn is dependent on
gestational age at the time of maternal primary infection.
 Varicella contracted in the first 13 weeks of pregnancy
results in fetal Varicella syndrome (FVS) in less than 1% of
cases.
 The risk of FVS rises to 2% with infections acquired between
week 13 and week 20 of gestation (Enders et al, 1994). The
skin, musculoskeletal system and central nervous system
are the main systems targeted in FVS with reported clinical
features including skin scarring, limb hypoplasia, cortical
atrophy, chorioretinitis and cataract. FVS does not occur
after maternal shingles (Enders and Miller, 1994). Prenatal
diagnosis is possible using detailed ultrasound for findings
such as limb deformity, microcephaly, hydrocephalus,
ventriculomegaly, porencephaly, soft tissue calcification,
chest wall malformations, intestinal and hepatic echogenic
foci, polyhydramnios, fetal hydrops, intrauterine growth
restriction or fetal demise. Congenital cataract and
micropthalmos are the most common ocular lesions but
these are not easily detected on ultrasound scan (Degani,
2006).
 Infections occurring as late as week 25 may still be
complicated by FVS.
 Maternal Varicella occurring at very late stages of
pregnancy, usually within 7 days of childbirth, may result in
17-50% of cases in disseminated neonatal varicella (Miller et
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al, 1989).
Peripartum and postnatal risks
There is a risk of developing neonatal varicella if maternal infection
occurs 7 days before or within 2 days after delivery. This is
because the development and transfer of protective antibodies will
not have had time to occur and the neonatal immune system is
relatively immature. Mortality is up to 30% without treatment
(Meyers, 1974). Infants born to VZV seronegative mothers are also
at risk of disseminated Varicella if they become exposed to the
virus within the first 7 days of life (Enders et al, 1994).
Management of the pregnant woman
At Booking visit
Enquire about a previous history of chickenpox. If there is no such
history, women must be advised to avoid contact with chickenpox
during pregnancy and to immediately inform health professionals
of a potential exposure. Women must be advised to inform a
health professional of any subsequent exposure to chicken-pox or
shingles as soon as possible.
Pregnant woman who reports a contact with chickenpox (or
shingles)
A careful history must be taken to confirm the significance of the
contact and the susceptibility of the pregnant woman to VZV.
A. Assessing the significance of a VZV contact:
For a contact to be regarded as significant the 3 criteria below
must be met:
1. The type of VZV in the index case should be one of the
following:
- Chickenpox
- Disseminated zoster
- Immunocompetent individual with exposed zoster (e.g.
Ophthalmic)
- Immunocompromised patient with localised zoster on
any part of the body (virus shedding presumed to be
greater).
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2. The index case should be infectious at the time of
exposure:
- Patients with chickenpox and disseminated shingles are
infectious from 48 hours before the rash appears until
cropping has ceased and all lesions have crusted over.
- Patients with localized shingles are infectious from the
day of onset of the rash until crusting.
3. There should be close contact with the index
case:
- Maternal/neonatal contact.
- Continuous house-hold contact.
- Contact in the same room, including large open wards,
for 15 minutes or more.
- Face to face contact, for example while having a
conversation.
B. Assessing maternal immunity:
If the pregnant woman have a history of chickenpox no ntervention
is required.
If there is no clear history of past chickenpox (i.e. negative or
uncertain) then a serum sample should be tested for the presence
of VZV IgG.
Telephone the Queens Medical Centre (QMC) on 0115 9249924
ext 67690 or 63524 (QMC) and ask to speak to the duty virologist
before sending the serum sample.
All requests for VZV IgG should include the following information to
enable the results to be timely reported with the correct
interpretation:
Full demographic details
Gestational age
Date and nature of VZV contact – must be a significant
contact (see above)
Name and telephone number of clinician/ midwife to whom the
result may be telephoned by virology
Women should be told that the results will usually be available on
the same day. They should which professional will contact them
with the results, this is usually the person who requested the test,
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or a designated deputy.
Use of varicella zoster immunoglobulin (VZIG) to prevent
severe chickenpox
A seronegative pregnant woman with a significant contact should
be offered VZIG, 1000mg IM (4 vials) as soon as possible and no
later than 10 days post exposure. The rationale for the use of VZIG
prophylaxis is to reduce the severity of maternal disease and
minimize the risk of fetal infection in the first 20 weeks of
pregnancy.
VZIG is available from NUH Pharmacy (QMC) through the duty
virologist/microbiologist. The VZIG MUST NOT be collected by
anyone who is infectious. The VZIG can be administered in the
community setting by either the practice nurse or midwife.
Clinical chickenpox will still develop in a proportion of women given
VZIG but it may be attenuated and/or delayed. Severe maternal
varicella may rarely occur despite VZIG. Women who have had
contact with chickenpox or shingles (regardless of whether or not
they have received VZIG) should be asked to notify a healthcare
professional if a rash develops.
VZIG is NOT indicated in pregnant women who develop
chickenpox.
Management of the pregnant woman who develops
chickenpox
Most pregnant women with chickenpox should be managed in the
community unless they are very sick.
Diagnosis:
The diagnosis of chickenpox is usually clinical (ie no laboratory
tests required). However, if the rash is atypical and VZV disease is
suspected, a vesicle swab should be obtained and sent to Virology
in virus transport medium (VTM) requesting VZV DNA detection.
Refrain from sending blood samples because serology has no role
in confirming chickenpox or shingles diagnoses and hence sending
blood samples is of little value.
Anti-viral therapy:
Aciclovir has been shown to reduce the duration of fever and
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hasten the resolution of vesicles if commenced within 24 hours of
onset of rash. Although it is not licensed in pregnancy, experience
has shown that it is a very safe drug and no adverse fetal or
neonatal effects have been reported with its use in pregnancy
(Briggs, et al. 2005). It should be used with caution in first trimester
due to insufficient evidence on its safety.
The guidelines from the Royal College of Obstetricians and
Gynaecologists (2007) restrict oral aciclovir to patients who:
a. present in the first 24 hours of rash
b. are more than 20 weeks pregnant.
However, aciclovir treatment may still be considered in patients
who are less than 20 weeks pregnant or whose onset of rash is
more than 24 hours but still developing new lesions if there is a
significant risk(s) of complications (Drugs and Therapeutics
Bulletin, 2005).
In each patient who develops chickenpox at less than 20 weeks
gestation, the risk-benefit of aciclovir treatment should be
assessed by an expert in the management of infections so that the
patient can make an informed decision. The International Aciclovir
pregnancy register performed a prospective study on 1129
patients of whom 729 had been given aciclovir and no adverse
outcomes were reported. It is usual practice in many countries to
treat pregnant women with antiviral therapy in all trimesters.
(Tunbrige et al, 2008)
In summary, aciclovir may be appropriate to give to the following
groups of patients:
 Any pregnant patient presenting within 24 hours of onset of
rash
 Patients who are still developing new crops of spots
 Patients who are smokers
 Patients who are on steroids
 Patients with symptoms/signs of respiratory tract involvement
Criteria for referral of pregnant women with chickenpox to hospital
1. If the patient develops any symptoms suggestive of
complications. Pregnant women should be advised to report
promptly any symptoms that suggest complications:
 difficulty breathing
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 confusion/headache
 a dense rash with or without mucosal lesions
 the appearance of new lesions after 6 days
 haemorrhagic rash or bleeding
2. If the pregnant woman is immunosuppressed, eg taking
steroids or has taken steroids within the last 3 months
3. Consider referral to hospital if the risk of Varicella
pneumonia is high, even in the absence of other
complications eg if the pregnant woman is smoker, has
chronic lung disease or has a dense rash – (Harger et al,
2002).
Inpatient management of pregnant women:
 Discuss all cases with the duty virologist
 Admit to an infectious diseases ward
 If admission to a maternity ward is unavoidable, women with
Varicella should be isolated from other pregnant women
 Commence intravenous aciclovir at 10 mg/kg three times a
day for 5 days at least (monitor the renal function and
maintain adequate hydration)
A management plan is decided in consultation with the
obstetrician, virologist and neonatologist (Nathwani et al, 1998).
Beware of risk of VZV transmission to other pregnant women
and/or immunocompromised inpatients.
If possible, delivery should be delayed until 7 days after onset of
maternal rash, to allow passive transfer of antibodies to neonates.
Management of the neonate exposed to chickenpox (or
shingles)
Neonates exposed to VZV should be referred to neonatologists.
obstetricians, General Practitioners (GPs), midwives and health
visitors should be aware of neonates who are at risk of severe
Varicella who meet any of the following 3 criteria:
1. The mother develops chickenpox (not shingles) in the
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period 7 days before to 7 days after birth.
2. Infants with significant non-maternal exposure to VZV within
the first 7 days of their life if their own or (their mother’s) VZV
IgG is negative.
3. Infants of any age with significant exposure to VZV while
still requiring care at Special Care Baby Unit/ Neonatal Unit if
their VZV IgG is negative.
Note that infants:
 born before 28 weeks’ gestation or
 weighing <1000g at birth or
 more than 60 days old or
 have had repeated blood sampling with replacement by
packed red cell infusion
may be VZV IgG negative despite a positive maternal history of
chickenpox. It is recommended that, where possible, such infants
are tested for VZV IgG in the event of significant VZV contact.
Post exposure prophylaxis:
1. High risk infants (criteria 1-3 above):
Give VZIG, 250mg IM (1 vial) as early as possible within 10
days of exposure.
2. Infants born in the highest risk period:
(rash in mother appears between 4 days before and 2 days
after delivery)
Give VZIG 250mg IM (1 vial).
In addition, PO aciclovir (10 mg/kg/dose, 400mg maximum
dose qds) starting from day 7 post contact for 7 days OR if
cannot take PO medications, IV aciclovir (5mg/kg/dose, tds)
should be given.
3. All other neonates with maternal or other exposure:
No need to give VZIG (monitor and give aciclovir if they
develop chickenpox).
Breast feeding:
Mothers with varicella should be allowed to breast feed. If they
have lesions close to the nipple, they should express milk from the
affected breast until the lesions have crusted; this expressed milk
can be fed to the baby if he/she is covered by VZIG and/or
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aciclovir.
Siblings with Varicella:
If other children in the family have varicella and the mother is
susceptible, contact with siblings with varicella should be delayed
until the new baby has reached seven days of age. If the mother
has had varicella or has been shown to have VZV IgG antibody,
then there is no reason to prevent a new baby going home.
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References
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(PA): Lippincott Williams & Wilkins.
Drug and Therapeutics Bulletin, 2005. Chickenpox, pregnancy and
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Degani S, 2006. Sonographic findings in fetal viral infections: a
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Enders G et al, 1994. Consequences of varicella and herpes
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