. 2021 May 26;40:e2020415. doi: 10.1590/1984-0462/2022/40/2020415

Table 3. Characteristics of studies related to SARS-CoV-2.

Author/year	Study population	Study design and intervention	Outcome measures	Conclusions
Juan et al., 2020 ²³	n=266 pregnant women.	Systematic review	One case of neonatal asphyxia and one of neonatal death. The case reports described two maternal deaths among pregnant women with COVID-19.	Clinical characteristics of pregnant women with COVID-19 are similar to those of non-pregnant adults with COVID-19.
Egloff et al., 2020 ²⁴	n=179 newbornstested for SARS-CoV-2 at birth.	Review	Transmission was suspected in eight cases, five with positive nasopharyngeal SARS-CoV-2 RT-PCR and three with SARS-CoV-2 IgM.	Current data indicate very rare maternal-fetal transmission but are largely incomplete.
Lamouroux et al., 2020 ²⁵ Alzamora et al., 2020 ²⁶	n=68 deliveries and 71 neonates with maternal infection.n=1 41-year-old pregnant woman with COVID-19.	Case report	Neonatal infection was diagnosed within 48 hours of life in four cases.Neonatal nasopharyngeal swab was positive for SARS-CoV-2.	More definitive evidence is needed for counseling pregnant women on the risk of congenital infection.Vertical transmission remains controversial.
Karimi-Zarchi et al., 2020 ²⁷	n=31 infected pregnant mothers.	Review	No COVID-19 infection was detected in their neonates or placentas. Two mothers died from COVID-19-related respiratory complications after delivery.	There is no evidence of intrauterine transmission. Mothers may be at increased risk for severe respiratory complications.
Schwartz et al., 2020 ²⁸	n=38 pregnant women.	Review	No deaths among the 38 pregnant women. No confirmed cases of intrauterine transmission of SARS-CoV-2.	There is no evidence of intrauterine or transplacental transmission.
Chen et al., 2020 ²⁹	n=9 pregnant women.	Retrospective review	No patient developed severe COVID-19 pneumonia or died. No neonatal asphyxia was observed in the newborns.	The clinical characteristics of pneumonia in pregnant women were similar to those reported for non-pregnant adult patients.
Lu et al., 2020 ³⁰	n=1 22-year-old pregnant woman.	Case report	COVID-19 nucleic acid test was three times negative in the newborn.	There might be no intrauterine infection caused by vertical transmission.