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Z
ika
virus
infection
and
pregnancy
R
ev
A
ssoc
M
ed
B
ras
2016; 62(2):108-115
109
clinical and laboratory testing following the criteria for di-
agnostic confirmation
8,9
(
D
) (compared to the previous ep-
idemiological week, in which 17 cases were confirmed, 24
new cases with identification of Zika virus were confirmed
in laboratory tests, totaling 41 cases). As for cases progress-
ing to miscarriage or postpartum death, 1.8% of the total
(91/5,079) were recorded. According to the classification,
64.8% (59/91) remained under investigation; 8.8% (8/91)
were investigated and discarded according to the case def-
inition, and 26.4% (24/91) were investigated and confirmed
for microcephaly and/or changes in the central nervous
system (CNS).
7
(
D
) A recent epidemiological report states
that until February 20, 2016 (epidemiological week SE
07/2016), 5,640 cases of microcephaly were reported and
of these only 583 were confirmed for either microcephaly
or CNS abnormalities suggestive of congenital infection.
9
(
D
)
CHART 1
Definition of microcephaly.
In newborns at term, the reference value used to define microcephaly
is a head circumference ≤ 32 cm at birth, according to the curves of
the World Health Organization (WHO). For newborns preterm, head
circumference below minus 2 standard deviations (SD), according to
Fenton curve.
CHART 2
Definition of congenital infection with Zika virus.
Presence of typical changes indicative of congenital infection such as
intracranial calcifications, dilation of cerebral ventricles or changes
in posterior
fossa
, and other clinical signs found by any imaging method,
or identification of Zika virus in laboratory tests.
Therefore, as noted, despite the increase seen in the num-
ber of cases of newborns diagnosed with microcephaly,
the total number of cases that are actually associated with
Zika virus infection is not known. Also, aspects of a cause
and effect relation between Zika virus infection and mi-
crocephaly, diagnosis, treatment, knowledge of the vire-
mic period, and factors related to increased risk to the fe-
tus, including recognition of the gestation period that is
more susceptible to the virus and monitoring of the new-
born, are not clarified. Thus, in order to build a robust
knowledge framework of the occurrence of this infection
among pregnant women and its effect on the fetus, pro-
spective studies with adequate follow-up are needed.
In view of the aspects explained above, the develop-
ment of clinical guidelines regarding the knowledge ac-
quired to date on an association between infection with
Zika virus and its effects on pregnancy and childbirth is
imperative in order to delimit and advise on panoramas
related to preconception counseling, prenatal, labor, post-
partum and newborn care.
O
bjectives
Prepare a clinical guideline that includes, in light of current
scientific evidence available, answers to clinical questions
structured according to the components of P.I.C.O. (P [Pa-
tient]; I [Intervention]; C [Comparison]; O [Outcome]).
M
ethods
The evidence used to evaluate the occurrence of infection
with Zika virus during pregnancy was obtained accord-
ing to the following steps: preparation of the clinical ques-
tion, structuring of the question, search for evidence, crit-
ical evaluation and selection of evidence.
Structured questions
1.
During pregnancy, what is the association between
Zika virus and microcephaly?
2.
What is the association between Zika virus and Guil-
lain-Barré syndrome? Is it different during pregnan-
cy? Can it affect the fetus?
3.
What are the symptoms in pregnant women with sus-
pected Zika virus infection? Are they different than
in the general population?
4.
How to make a definitive diagnosis of Zika virus in-
fection during pregnancy?
5.
What is the treatment for Zika virus infection during
pregnancy?
6.
How is follow-up of pregnant women infected with
Zika virus done?
7.
What are the precautions to be taken with babies born
from pregnant women with a history of Zika virus in-
fection?
8.
What is the care required for newborns diagnosed with
microcephaly during pregnancy?
Databases consulted
Primary scientific databases consulted were Medline, Em-
base and Cochrane. A manual search from the referenc-
es of narrative reviews was also performed. See in Chart
3 the databases consulted and respective search strate-
gies. Chart 4 displays the number of studies retrieved
from each scientific database until 2/23/16.
CHART 3
Primary databases consulted and search
strategy.
Medline: (Zika Virus OR Virus, Zika OR ZIKV OR Flavivirus OR
Flaviviruses OR Arbovirus, Group B OR Arboviruses, Group B OR
Group B Arbovirus OR Group B Arboviruses) AND (Pregnancy OR
Pregnancies OR Gestation).
Embase: ‘pregnancy’/exp AND ‘flavivirus’/exp.
Cochrane: (Zika Virus AND Pregnancy).