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Table 1 Characteristics of included studies

From: Differences in pregnancy and perinatal outcomes among symptomatic versus asymptomatic COVID-19-infected pregnant women: a systematic review and meta-analysis

Study and year

Study design

Country and time period

Setting

Total number

Demographics

Past Medical History

Symptomatic

asymptomatic

Symptomatic

Dongmei Cao 2020 [23]

Case-series

Wuhan, China

Jan 23rd to Feb 23rd 2020

Maternal and Child health hospital

Total = 10

Symp = 7

Asymp = 3

Mean age:30.6

Mean Gest. Age: 37 + 6

Mean Age: 29.7

Mean Gest. Age: 37 + 5

Hypothyroid = 1

Anemia = 1

Ensiyeh Jenabi, 2020 [26]

Case-control

Hamadan Province,

Iran

Sept 1 to Nov 15, 2020

Hospitals of Hamadan Province located in West Iran

Total = 90

Symp = 45

Asymp = 45

Mean age = 29.47

Mean Gestational age = 37.13

Mean age = 28.78

Mean Gestational age = 37.62

Comorbidity disease = 3

Gabrielle Saccone 2020 [17]

Retrospective cohort

22 different countries (Argentina, Australia, Belgium, Brazil, Colombia, Czech Republic, Finland, Germany, Greece, Israel, Italy, North Macedonia, Peru, Portugal, Republic of Kosovo, Romania, Russia, Serbia, Slovenia, Spain, Turkey, and United States)

February 1, 2020 and April 30, 2020

Various hospitals

Total = 388

Symp = 294

Asymp = 94

N/A

N/A

N/A

Jayasree Santhosh2020 [18]

Cohort study

Muscat, Oman

March 24 to July 31, 2020

The Royal Hospital

Total = 60

Symp = 44

Asymp = 16

N/A

N/A

Hypertension = 1

Diabetes = 2

GDM = 12

Hematologic disease = 7

Nicola Vousden2021 [19]

Prospective Cohort

United Kingdom

March 1 to August 31, 2020

194 hospitals vis UK Obstetric Surveillance System (UKOSS)

Total = 1148

Symp = 722

Asymp = 426

Race-ethnicity:

White = 318

Asian = 210

Black = 122

Chinese = 8

Other = 36

Mixed = 15

Current smoking = 42

Race-ethnicity:

White = 276

Asian = 84

Black = 33

Chinese = 4

Other = 16

Mixed = 5

Current smoking = 57

Asthma = 49

Hypertension = 24

Cardiac disease = 13

Diabetes = 22

Sourabh Verma, 2020 [20]

Cohort study

New York,

USA

March 1 to May 10, 2020

New York University (NYU) Langone Health system hospitals (NYU Tisch, NYU Brooklyn, NYU Winthrop) and Bellevue Hospital Center

Total = 149

Symp = 89

Asymp = 60

Mean age = 32

BMI (> = 30) = 38

Mean age = 30.4

BMI (> = 30) = 24

Asthma = 6

Diabetes = 2

Gestational Diabetes = 5

Gestational hypertension = 12

Torri Metz 2021 [21]

Cohort study

14 states

USA

March 1st to July 31st, 2020

33 National Institute of

Child Health and Human Development (NICHD)

Maternal-Fetal Medicine Units (MFMU) sites

Total = 1219

Symp = 640

Asymp = 579

Mean Age = 30

BMI (> = 30) = 328

Race-ethnicity:

Black = 152

White = 101

Hispanic = 327

Smoked = 23

Mean Age = 28

BMI (> = 30) = 561

Race-ethnicity:

Black = 123

White = 80

Hispanic = 324

Smoked = 27

Asthma or COPD = 114

Pregestational Diabetes = 32

Hypertension = 51

Cardiovascular disease = 11

Chronic renal disease = 3

Chronic liver disease = 5

Thyroid disease = 32

Neurocognitive disorder = 25

Neuromuscular disorder = 3

Seizure disorder = 10

Inflammatory bowel disease = 3

Viktoriya London 2020 [22]

Retrospective Cohort study

Brooklyn, NY, United States of America From March 15th to April 10th 2020

Maimonades Medical Centre

Total = 68

Symp = 46

Asymp = 22

Mean age = 30

BMI = 31

Gestational age = all in 3rd trimester

(except 17wks (n = 1), 25 wks (n = 1) and 26 wks (n = 1)

Nulliparity = 12

Mean age = 30.5

BMI = 31.6 Gestational age = all third trimester

Nulliparity = 8

Comorbidity = 15/46 Preeclampsia = 2

Xiaolin Hu 2020 [25]

Case series

Wuhan, China

Jan 20th to Feb 20th

Tongji Medical college

Total = 7 Symp = 6

Asymp = 1

32.7 + −  1.6 Gestational Age = 39 + 1

33 Gestational age = 38 + 2

N/A

Xiaoqing Wu 2020 [24]

Case series

Wuhan, China

Dec 31st to March 17th 2020

Central Hospital of Wuhan

Total 19

Symp = 7

Asymp = 12

Mean age = 28.3

Mean age = 29.1

Hepatitis B = 1

PIH = 0

Hypothyroid = 0

Study and year

Past Medical History

Management

Delivery and Neonatal Characteristics and Outcomes

Complications

Asymptomatic

Symptomatic

Asymptomatic

Symptomatic

Asymptomatic

Symptomatic

Asymptomatic

Dongmei Cao 2020 [23]

Comorbid = none

N/A

N/A

Vaginal birth = 1

Total CD = 6

Elective CD = 4

Intrapartum = 2

Livebirths = 7/7

Birthweight = 3112.14

Neonatal asphyxia = 0

Preterm birth = 2

1 min Apgar score = 8.7

5 min Apgar score = 10

Neonatal death = 0

Neonatal PCR = all negative

Vaginal birth = 1

Total CD = 2

Elective CD = 2

Intrapartum CD = 0 Livebirths = 4/3 (single pair of twins)

Birthweight = 3215

Neonatal asphyxia = 0

Preterm birth =1(twins)

1 min Apgar score = 8.3

5 min Apgar score = 10

Neonatal death = 0

Neonatal PCR = all negative

GDM = 1

Pre-eclampsia = 3

Placental abruption = 1

Fetal distress = 1

PROM = 2

Preterm = 2

Neonatal death = 0

GDM = 0

Pre-eclampsia = 0

Placental abruption = 0

Fetal distress = 1

PROM =2

Preterm- = 1

Neonatal death = 0

Ensiyeh Jenabi, 2020 [26]

Comorbidity disease = 19

N/A

N/A

Preterm labour = 12

C-section = 27

LBW = 12

Neonatal death = 2

Preterm labour = 6

C-section = 12

LBW = 4

Neonatal death = 1

Preeclampsia = 11

Preeclampsia = 4

Gabrielle Saccone 2020 [17]

N/A

N/A

N/A

C-section = 100/177

Mean birthweight = 2821 ± 846

IUGR = 9/189

Admission to NICU = 50/177

LBW = 43/177

Neonatal Death = 5/177

C-section = 36/74

Mean birthweight = 3149 ± 496

IUGR = 1/77

Admission to NICU = 19/74

LBW = 9/74

Neonatal death = 0/74

Maternal ICU admission = 42/294

Mechanical ventilation = 35/294

Maternal ICU

admission = 1/94

Mechanical ventilation = 1/94

Jayasree Santhosh2020 [18]

Hypertension = 2

Diabetes = 3

GDM = 3

Hematologic disease = 1

N/A

N/A

Normal Vaginal = 19

Instrumental delivery = 1

Elective C-section = 4

Emergency C-section = 12

Preterm birth = 12

Stillbirth = 1

LBW = 9

Normal Vaginal = 5

Instrumental delivery = 3

Elective C-section = 2

Emergency C-section = 3

Preterm birth = 6

Stillbirth = 0

LBW = 6

Preterm PROM = 1

Miscarriage = 1

Preterm PROM = 0

Miscarriage = 0

Nicola Vousden2021 [19]

Asthma = 28

Hypertension = 2

Cardiac disease = 8

Diabetes = 6

Oseltamivir = 11

Steroids = 120

N/A

C-section = 314

Vaginal = 308

Preterm birth (< 37 weeks) = 114

Stillbirth = 5

Live birth = 627

NICU admission = 121

Neonatal death = 2

C-section = 153

Vaginal = 228

Stillbirth = 4

Live birth = 381

NICU admission = 35

Neonatal death = 2

Required critical care = 63

COVID-19 pneumonia = 173

Pre-eclampsia = 15

Death = 8

N/A

Sourabh Verma, 2020 [20]

Asthma = 6

Diabetes = 2

Gestational Diabetes = 5

Gestational hypertension = 5

N/A

N/A

Alive = 89

C-section = 23

Preterm birth (<  37 weeks) = 14

NICU admission = 17

Neonatal death = 1

Positive neonatal RT-PCR = 1/66

Alive = 60

C-section = 13

Preterm birth (<  37 weeks) = 2

NICU admission = 1

Neonatal death = 0

Positive neonatal RT-PCR = 0/21

ICU admission = 8

ICU admission = 9

Torri Metz 2021 [21]

Asthma or COPD = 51

Pregestational Diabetes = 17

Hypertension = 29

Cardiovascular disease = 3

Chronic renal disease = 0

Chronic liver disease = 1

Thyroid disease = 22

Neurocognitive disorder = 10

Neuromuscular disorder = 1

Seizure disorder = 4

Inflammatory bowel disease = 0

N/A

N/A

C-section = 253

Preterm birth (<  37 weeks) = 135

Live births = 626

SGA = 70

Birthweight = 3.5

NICU admission = 163

C-section = 197

Preterm birth (less than 37 weeks) = 69

Live births = 570

SGA = 56

Birthweight = 3.2

NICU admission = 91

Maternal death = 6

Venous thromboembolism = 9

Maternal ICU admission = 56

Postpartum hemorrhage = 66

Hypertensive disorder of pregnancy = 176

Neonatal death = 3

Maternal death = 0

Venous thromboembolism = 0

Maternal ICU admission = 3

Postpartum hemorrhage = 42

Hypertensive disorder of pregnancy = 109

Neonatal death = 2

Viktoriya London 2020 [22]

Comorbidity = 4/22 Preeclampsia = 1

Hydroxychloroquine and azithromycin = 16

Respiratory support = 12

[nasal cannula (n = 7); nonrebreather mask (n = 3); Hi-flow nasal cannula (n = 1); Mechanical ventilation (n = 1)

Hydroxychloroquine and azithromycin = 0

Respiratory support = 0

C-section = 16

Preterm < 37 wks = 9

Preterm < 34 wks = 3

Preterm due to: maternal respiratory distress (n = 7); decreased fetal movements (n = 1)

C-section = 6

Preterm < 37 wks = 0

Preterm < 34 wks = 0

N/A

N/A

Xiaolin Hu 2020 [25]

N/A

Anti-viral = 1

Anti-viral = 0

SVD = 1

C-section = 5 Birthweight = 3356.67

1 min Apgar = 8

5 min Apgar = 9 COVID RT-PCR = 1 positive

SVD = 0

C-section = 1

Birthweight = 3180

1 min APGAR = 7

5 min APGAR = 8 Covid RT-PCR = all negative

Liver dysfunction

No complications

Xiaoqing Wu 2020 [24]

Hepatitis B = 1

PIH = 3

Hypothyroid = 1

N/A

N/A

N/A

N/A

PROM = 0

Fetal intrauterine hypoxia = 0

PROM = 1

Fetal intrauterine hypoxia = 1

  1. Asymp Asymptomatic pregnant women, BMI Body Mass Index, C-section Cesarean section, Chr Chronic, GDM Gestational Diabetes Mellitus, ICU Intensive Care Unit, IUGR Intrauterine Growth Retardation, LBW Low Birth Weight, NICU Neonatal Intensive Care Unit, PCR Polymerase Chain Reaction, PIH Pregnancy Induced Hypertension, PROM Premature Rupture of Membranes, SVD Spontaneous vaginal delivery, Symp Symptomatic pregnant women, Wks weeks