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. 2021 Sep 20;13(9):1877. doi: 10.3390/v13091877

Table 1.

Features of the included studies.

Study Database(s) Date of Publication Number of Included Studies Number of Pregnant Women Number of Newborns Number of Infected Newborns Maternal Deaths Newborns Deaths Cesarean Delivery Remark (Vertical Transmission) Sensitivity Analysis in Studies with Meta-Analysis
AbdelMassih et al. [19] Embase, MEDLINE, Cochrane April, 2021 64 1787 1787 45 (2.5) NA 19 NA Unlikely Y
Abdollahpour et al. [33] PubMed, Scopus, Embase,
Science direct, ClinicalKey, PsycINFO, manual
searches of other relevant papers		 May, 2020 29 NA 2 NA NA NA NA No direct evidence NM
Abou Ghayda et al. [16] PubMed, Scopus, MEDLINE, Google Scholar, Embase October, 2020 11 104 NA NA NA 6 (5.8) 52 Vertical infection was not found NM
Akhtar et al. [20] MEDLINE, PubMed, Scopus, Google Scholar July, 2020 22 156 108 7 8 3 66 No evidence to support vertical transmission NM
Allotey et al. [22] MEDLINE, Embase, Cochrane database, WHO COVID-19
database, CNKI, Wanfang, L·OVE		 September, 2020 77 11432 NA NA <1% <1% 1060 (65% (57–73%) 95% CI) Not reported Y
Amaral et al. [34] Embase, PubMed database November, 2020 70 1457 1042 39 (3.7%) 15 (1%) 16 (1.5%) 15% Low evidence to support vertical transmission NM
Arroyo-Sanchez et al. [34] MEDLINE/PubMed, ScienceDirect,
ClinicalKey, LILACS, SciELO, Google Scholar,
medRxiv, and
SciELO Preprints.		 2020 30 476 476 9 (1.9%) Probable NM
Ashraf et al. [35] PubMed, Scopus, WoS, Embase, Google Scholar July–September, 2020 21 90 92 4 1 1 81 Possible but rare NM
Banaei et al. [36] MEDLINE, Embase, Scopus, WoS, ProQuest, Google
Scholar		 2020 16 123 124 5 0 1 99 Probable NM
Barcelos et al. [37] PubMed, Scopus, Embase Accepted November, 2020 27 NA NA 9 NA NA NA Possible, with low risk NM
Bwire et al. [38] PubMed/MEDLINE, Google Scholar Accepted October, 2020 33 205 205 13 (6.3%) NA NA 71.9% Low possibility of vertical transmission NM
Cai et al. [39] PubMed, Embase, Cochrane Library, Web of Science, Google Scholar, CBM February, 2021 68 1019 1035 34 (3.29%) 14 6 59.71% Possible NM
Capobianco et al. [40] PubMed, Scopus Accepted July, 2020 13 114 108 5 0 2 95 Low probability of vertical transmission N
Chamseddine et al. [41] PubMed, medRxiv October, 2020 48 245 201 6.45% 8 (3.2%) 2.5% 89% Possible NM
Chi et al. [42] PubMed/MEDLINE, Embase, Cumulative Index to Nursing and Allied Health Literature, National Digital Library of Theses and Dissertations in Taiwan, Art Image Indexing Service on the Internet, Cochrane February, 2021 14 107 105 8 (8.8%) NA NA 87.6% Possible NM
Della Gatta et al. [43] PubMed, Scopus, CINAHL July, 2020 6 51 48 1 NA 1 46 No evidence of vertical transmission NM
Deniz & Tezer [44] medRxiv, PubMed July, 2020 50 714 606 20 NA NA NA Potentially vertically transmit-ted NM
Dhir et al. [45] MEDLINE, Embase, Web of Science August, 2020 86 1992 1141 58 NA 0 66% Possible, with low risk NM
Di Mascio et al. [46] MEDLINE, Embase, CINAHL, ClinicalTrials.gov May, 2020 6 41 42 0 0 2.4% 38 None has been reported N
Di Toro et al. [25] PubMed, Embase, medRxiv, Scholar, Scopus, Web of Science January, 2021 24 588 444 19 5 3 85% No evidence of vertical transmission N
Diriba et al. [47] PubMed, Web of Science, Embase, Google Scholar, Cochrane September, 2020 23 1271 NA 0 1.5% 1.2% 57% No evidence of vertical transmission Y
Amaral et al. [34] PubMed, Embase November, 2020 70 1457 1112 39 15 16 597 (57.3%) Possible NM
Dube et al. [48] PubMed, Embase, LitCovid, medRxiv, bioRxiv, Google Scholar, EBSCO MEDLINE, CINAHL, Scopus November, 2020 72 NA 1408 51 (3.67%) NA NA 59.9% Possible but low NM
Dubey et al. [49] PubMed September, 2020 61 790 548 NA NA NA 72% None reported Y
Duran et al. [50] Google Scholar, LILACS, PubMed May, 2020 20 195 222 13 NA 1 48 Probable NM
Elshafeey et al. [51] LitCovid, EBSCO MEDLINE, CENTRAL, CINAHL, Web of Science, Scopus May, 2020 33 385 256 4 1 1 175 (69.4) Probable NM
Galang et al. [52] MEDLINE, ClinicalTrials.gov August, 2020 31 98 94 8 1 1 72 Probable NM
Gao et al. [53] PubMed, Web of Science, Embase, MEDLINE August, 2020 14 236 NA 1.8% NA 1 69% No evidence available Y
Ghayda et al. [16] PubMed, Scopus, MEDLINE, Google Scholar, Embase October, 2020 11 104 NA 0 7 5 fetal + 1 neonatal 50% No vertical transmission reported N
Gordon et al. [54] CINAHL, Embase, MEDLINEMEDLINE, PubMed May, 2020 8 NA 46 7 NA 0 86% Likely NM
Han et al. [55] MEDLINE, PubMed, Web of Science, Cochrane, CNKI, Wanfang Data, VIP, SinoMed, ClinicalTrials.gov October, 2020 36 1103 NA <0.01% <0.01% <0.01% 28.59% Unlikely NM
Hassanipour et al. [56] PubMed, Embase, Scopus, Web of Science, Google Scholar December, 2020 10 135 NA 1 NA 1 84% Low evidence for vertical transmission N
Huntley et al. [57] MEDLINE, Ovid, ClinicalTrials.gov,
medRxiv, Scopus		 August, 2020 13 538 435 0 0 1 85% None reported NM
Islam et al. [58] PubMed, Embase, Scopus,
Google Scholar, Web of Science		 December, 2020 13 235 NA 0 NA NA 156 (66.38%) Not reported N
Jafari et al. [59] Embase, Scopus, PubMed, Web of Science, Cochrane January, 2021 121 NA 8% NA NA 2.5% 48% Possible N
Juan et al. [60] PubMed, Embase, Cochrane, CNKI, Wanfang Data May, 2020 24 324 240 3 7 1 78.1% Possible NM
Karabay et al. [61] MEDLINE, Web of Science, PubMed, ScienceDirect, CINAHL, Scopus, Cochrane, TUBiTAK November, 2020 35 NA NA 68 NA 0 NA Possible NM
Kasraeian et al. [62] PubMed, Google Scholar, medRxiv, UpToDate search engines May, 2020 9 87 86 0 0 0.2% 92.2% Not reported Y
Khalil et al. [63] MEDLINE, Embase, ClinicalTrials.gov, Cochrane August, 2020 86 2567 NA 1.4% 0.9% 0.6% 48.3% Possible N
Kotlyar et al. [13] PubMed, Embase, medRxiv, bioRxiv Jan, 2021 69 1566 936 27 (3.2%) NA NA 73% Possible Y
Lopes de Sousa et al. [64] PubMed, Scopus, Embase, ScienceDirect, WoS, Google
Scholar, bioRxiv, medRxiv		 June, 2020 49 755 598 1.8% 8 10 64.7% No concrete evidence of vertical transmission NM
Matar et al. [65] Ovid MEDLINE and Epub Ahead of Print, In-Process
and Other Nonindexed Citations, Ovid Embase,
Ovid Cochrane Central Register of Controlled Trials,
Scopus		 June, 2020 24 136 94 2 1 3 76.3% Probable N
Melo et al. [66] PubMed, Scopus, LILACS, Web of Science, Google Scholar, Preprints, bioRxiv, medRxiv July, 2020 38 520 NA 16 NA NA NA Possible Y
Mirbeyk et al. [67] PubMed, Web of Science, Google Scholar, Scopus, WHO COVID-19 database April, 2021 37 386 302 5% 2 3 86% Possible, with low evidence NM
Muhidin et al. [68] PubMed, Scopus, Embase, ProQuest, ScienceDirect April, 2020 9 89 89 0 0 2.2% 91.9% No evidence NM
Najafi et al. [69] PubMed, Scopus, Google Scholar December, 2020 20 NA 145 7 NA 10% NA Low risk of vertical transmission NM
Neef et al. [70] PubMed, Google Scholar, Web of Science October, 2020 32 258 261 12 NA 3 NA The risk of vertical transmission is low N
Novoa et al. [21] MEDLINE, Embase, Cochrane Library, LILACS, CNKI, VIP, Wanfang Data January–February, 2021 37 322 195 16 1 1 99 (50.8%) No concrete evidence to support vertical transmission N
Oltean et al. [71] MEDLINE, Embase, Google Scholar, WHO database on COVID-19, Disaster Lit: Database, medRxiv, and OSF Preprints March, 2021 41 315 262 3.1% NA 1 NA Vertical transmission has yet to be confirmed NM
Oshay et al. [72] PubMed, Embase, World Health Organization, Google Scholar July, 2021 67 427 304 3.2% 8 NA NA Low risk of vertical transmission NM
Papapanou et al. [17] PubMed, Scopus, Cochrane January, 2021 39 NA NA 1.6–10% <2% <3% 52.3–95.8% Probable NM
Pastick et al. [73] PubMed/MEDLINE August, 2020 126 11308 10597 NA 33 0.7% 70% Not reported NM
Pettirosso et al. [74] MEDLINE, Embase, WHO COVID-19 database, Cochrane August, 2020 60 1287 NA 19 8 6 NA Possible NM
Raschetti et al. [75] PubMed, Cochrane, Web of Science, bioRxiv, and medRxiv October, 2020 74 NA NA 53 NA NA NA Confirmed/possible N
Rodrigues et al. [76] PubMed, Scopus, Web of Science, medRxiv November, 2020 161 3985 2015 61 28 10 53.92% Possible NM
Smith et al. [23] PubMed, MEDLINE, Embase June, 2020 9 92 60 1 0 1 80% Probable NM
Thomas et al. [77] Ovid MEDLINE, Embase, CENTRAL July, 2020 18 157 160 5 1 1 115 (73%) No conclusive evidence to support vertical transmission NM
Tolu et al. [24] PubMed, CINAHL, Web of Science, Scopus, CENTRAL April, 2021 51 NA 336 15 NA NA 265 (78.8%) Not enough evidence on vertical transmission NM
Trippella et al. [78] MEDLINE, Embase, Google Scholar, medRxiv June, 2020 37 275 248 16 1 1 74.9% Possible NM
Trocado et al. [79] PubMed, Scopus database, and WHO database July, 2020 8 95 51 1 0 1 94% Probable NM
Turan et al. [80] PubMed, Ovid MEDLINE, WoS, China Academic
Literature Database		 July, 2020 63 637 479 8 10 5 83% Probable NM
Vergara-Merino et al. [18] PubMed/MEDLINE, Embase, other electronic databases, clinical trials registries, and preprint repositories, among other sources relevant to COVID-19 February, 2021 52 NA NA 0–11.5% 0–11.1% 0–11.7% 48.3–100% Possible NM
Walker et al. [81] MEDLINE, Embase, Maternity and Infant Care Database June, 2020 49 655 666 28 NA NA 5.3% Probable NM
Yang et al. (a) [82] PubMed, Google Scholar, CNKI, Wanfang Data, VIP,
CBMdisc		 April, 2020 18 114 NA 7 NA 1 90.8% No direct evidence NM
Yang et al. (b) [83] PubMed, CNKI, CBMdisc, Wanfang Data 2020 22 NA 83 9 NA NA 88% No direct evidence NM
Yee et al. [84] PubMed, Embase, WoS October, 2020 9 93 103 4 NA 0 NA No direct evidence N
Yoon et al. [85] PubMed/MEDLINE, Embase 2020 28 223 201 4 NA 1 88.1% Probable NM
Yuan et al. [86] PubMed, MEDLINE, CBM, Wanfang 2021 29 564 555 18 NA NA 62.8% No sufficient evidence to exclude the possibility of vertical transmission NM
Zaigham et al. [87] MEDLINE, Embase, Google Scholar April, 2020 18 108 87 1 0 1 92% Probable NM

Abbreviation: NA: Not available; Remark: Conclusion remarks drawn from the included systematic reviews studies on vertical transmission of SARS-CoV-2; Y: Yes; N: No; NM: No Meta-analysis.