Comment on: "A systematic review of pregnant women with COVID-19 and their neonates".

Dear Editor,

We read with great interest the article by Mirbeyk et al. entitled “A systematic review of pregnant women with COVID-19 and their neonates” (volume 304, issue 1) [1]. The authors aimed to summarize and review the published studies concerning pregnant women with confirmed COVID-19 and their neonates. The authors should be applauded for establishing a timely and informative systematic review and sheds light on this infection in a particular group. However, as we thoroughly examined the details of this review, we noticed a few points we would like to address and discuss.

First, the authors stated that “The present systematic review was developed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement” in the Methods section. However, we cannot find the PRISMA checklist and registration number in the manuscript or supplementary files. Furthermore, the authors should present a full electronic search strategy for at least one database as online supplemental files, including any limits used, such that it could be repeated [2]. The authors should assess the risk of bias in individual studies according to the PRISMA recommendations, which are mandatory for any systematic review [2].

Second, the authors should clearly state what a pregnant woman with confirmed COVID-19 is. Did the authors mean a confirmed case is diagnosed by laboratory test (RT-PCR or serological test)? The authors should make it clear and adopt a uniform case definition throughout the manuscript.

Third, according to the Selection criteria, only original articles published in English were eligible. However, we noted three articles published in Chinese [3-5], one preprint article without peer-reviewed [6], and one retraction article [7] also included in this systemic review.

Fourth, most important of all, the authors did not extract the name of hospitals and the periods of recruitment, which means that the authors included studies suspected of duplicate reporting. Table 1 shows details of the included articles and duplicates reporting. Including duplicates reporting in a review may create an inaccurate scientific record and may affect understanding the disease and its epidemiology [8]. Thus, we suggest that the authors should review the hospital and periods of recruitment. When a hospital had published their cases more than once, if the periods of recruitment overlapped, only the study with the biggest data was included to minimize the possibility of double counting.

Table 1

Details of the included articles and duplicates reporting

Title	Hospitals	Periods of recruitment (2020)	Language of publication	suspected of duplicate reporting
Pregnant women with new coronavirus infection: a clinical characteristics and placental pathological analysis of three cases	Wuhan Union Hospital	1.21–2.25	Chinese	No
Pregnancy and perinatal outcomes of women with coronavirus disease (COVID-19) pneumonia: a preliminary analysis	Wuhan Union Hospital	1.20–2.10	English	No
Anesthetic management for emergent cesarean delivery in a parturient with recent diagnosis of coronavirus disease 2019 (COVID-19): a case report	Wuhan Union Hospital	2.06–2.13	English	No
Clinical analysis of 10 neonates born to mothers with 2019-nCoV pneumonia	Four hospitals from Hubei province	1.20–2.05	English	No
Clinical characteristics and intrauterine vertical transmission potential of COVID-19 infection in nine pregnant women: a retrospective review of medical records	Zhongnan Hospital	1.20–1.31	English	Yes (smaller sample)
Clinical characteristics and risk assessment of newborns born to mothers with COVID-19	Zhongnan Hospital	1.20–1.29	English	Yes (bigger sample)
Antibodies in infants born to mothers with COVID-19 pneumonia	Zhongnan Hospital	2.16–3.06	English	No
Analysis of the pregnancy outcomes in pregnant women with COVID-19 in Hubei Province	Renmin Hospital	1.30–2.17	Chinese	No
Perinatal transmission of COVID-19 associated SARS-CoV-2: should we worry?	Renmin Hospital	1.10–2.17	English	No
Possible vertical transmission of SARS-CoV-2 from an infected mother to her newborn	Renmin Hospital	1.28–2.22	English	No
Association of COVID-19 infection with pregnancy outcomes in healthcare workers and general women	Renmin Hospital	1.25–2.15	English	No
Impact of COVID-19 infection on pregnancy outcomes and the risk of maternal-to- neonatal intrapartum transmission of COVID-19 during natural birth	Renmin Hospital	1.28–3.01	English	No
Lack of vertical transmission of severe acute respiratory syndrome coronavirus 2, China	The First Affiliated Hospital, College of Medicine, Zhejiang University	2.06–2.19	English	No
A case of 2019 novel coronavirus in a pregnant woman with preterm delivery	Suzhou Municipal Hospital	2.05–2.18	English	No
A case report of neonatal COVID-19 infection in China	Tongji Hospital	2.01–2.18	English	Yes (smaller sample)
Clinical features and obstetric and neonatal outcomes of pregnant patients with COVID-19 in Wuhan, China: a retrospective, single-center, descriptive study	Tongji Hospital	1.01–2.18	English	Yes (bigger sample)
Coronavirus disease 2019 (COVID-19) during pregnancy: a case series	Tongji Hospital	Not mention	Not published, not peer-reviewed	Unknown
Clinical characteristics of 19 neonates born to mothers with COVID-19	Tongji Hospital	1.31–2.19	English	No
Clinical analysis of pregnant women with 2019 novel coronavirus pneumonia	Maternal and Child Hospital of Hubei Province	1.20–2.10	English	No
Maternal and neonatal outcomes of pregnant women with COVID-19 pneumonia: a case–control study	Maternal and Child Hospital of Hubei Province	1.24–2.29	English	No
Clinical features and outcomes of pregnant women suspected of coronavirus disease 2019	Maternal and Child Health Hospital of Hubei Province	1.20–3.05	English	No
Infants born to mothers with a new coronavirus (COVID-19)	Maternal and Child Health Hospital of Hubei Province	1.20–3.05	English	No
Lung ultrasound and computed tomographic findings in a pregnant woman with COVID-19	Ankara University, Faculty of Medicine	Not mention	English	No
A pregnant woman with COVID-19 in Central America	Hospital Escuela of Tegucigalpa	Not mention	English	No
Neonatal early-onset infection with SARS CoV-2 in 33 neonates born to mothers with COVID-19 in Wuhan, China	Wuhan Children's Hospital	1.30–2.15	English	No
Mortality of a pregnant patient diagnosed with COVID-19: a case report with clinical, radiological, and histopathological findings	Vali-e-asr Hospital	Not mention	This article has been withdrawn at the request of the authors	No
Unlikely SARS-CoV-2 vertical transmission from mother to child: a case report	Chongqing University Three Gorges Hospital	2.05–2.19	English	Yes (same patient)
Chest CT findings in a pregnant patient with 2019 novel coronavirus disease	Chongqing University Three Gorges Hospital	2.09–2.21	English	Yes (same patient)
Severe COVID-19 during pregnancy and possible vertical transmission	British American Hospital	3.29–4.03	English	No
Preterm delivery in a pregnant woman with critical COVID-19 pneumonia and vertical transmission	Mazandaran University of Medical Sciences	3.07–3.26	English	No
Vaginal delivery report of a healthy neonate born to a convalescent mother with COVID-19	Beijing YouAn Hospital	3.07–3.10	English	No
COVID-19 infection among asymptomatic and symptomatic pregnant women: 2 weeks of confirmed presentations to an affiliated pair of New York City hospitals	New York Presbyterian Hospital	3.13–3.27	English	No
COVID-19 in pregnancy: early lessons	New York Presbyterian Hospital	Not mention	English	No
Asymptomatic COVID-19 in pregnant woman with typical chest CT manifestation: a case report	Yichun people's Hospital	2.12–2.21	Chinese	No
Clinical manifestations and outcome of SARS-CoV-2 infection during pregnancy	Hospital in areas outside Wuhan	1.01–2.25	English	Yes
Novel coronavirus infection in newborn babies under 28 days in China	Chinese National Health Commission (which stores the medical records of all 50 designated hospitals in Wuhan city)	1.01–3.13	English	Yes
Clinical characteristics of pregnant women with COVID-19 in Wuhan, China	Chinese National Health Commission (which stores the medical records of all 50 designated hospitals in Wuhan city)	1.01–3.20	English	Yes