Evaluation of pregnancy outcomes in mothers with COVID-19 infection: a systematic review and meta-analysis

Figures & data

Figure 1. Flowchart of the literature search for the systematic review.

Table 1. Characteristics of cohort and case-control studies included in the meta-analysis.

First author	Title	Country	Study design	Sample size	Feto-maternal outcomes	Neonatal outcomes
1. Manas Kumar Nayak	Neonatal outcomes of pregnant women with COVID-19 in a developing country setup	India	Cohort	162 mothers and 165 neonates	PROM: 25 (15.4%); meconium-stained liquor: 39 (24.07%); PPH: 2 (1.2%); maternal mortality: 1 (0.6%); preterm (<37 weeks): 27 (16.6%); late preterm (34–36 + 6): 17 (10.3%); very preterm (28–33 + 6): 9 (5.4%); extreme preterm (<28 weeks): 1 (0.6%); stillbirth: 2 (5.2)	LBW: 49 (29.7%); prematurity (<37 weeks): 27 (71%); RDS: 8 (21%); hypoglycaemia: 4 (10.5%); hyperbilirubinemia requiring phototherapy: 15 (39.5%); necrotising enterocolitis: 1 (2.6%); hypoxic ischemic Encephalopathy (grade II or III): 6 (15.8%); NICU admission: 38 (23%); mortality (<28 days): 5 (13.2%), SARS-CoV2 positive neonates: 3/32 (9.4%)
2. Madalina Timircan	Exploring pregnancy outcomes associated with SARS-CoV-2 infection	Romania	Cohort	101+ vs. 938–	PIH: 6 (6%) vs. 28 (3%); preeclampsia: 2 (2%) vs. 19 (2%); GDM: 5 (5%) vs. 66 (7%); PROM: 11 (11%) vs. 55 (6%), *p = .049	Prematurity: 15 (15%) vs. 75 (8%), *p < .001; ICU admission: 6 (6%) vs. 27 (3%); foetal malformations: 2 (2%) vs. 19 (2%); neonatal sepsis: 5 (5%) vs. 56 (6%); neonatal death: 1 (1%) vs. 4 (0.5%); SARS-CoV-2 infection: 2 (2%)
3. Jean Y. Ko	Adverse pregnancy outcomes, maternal complications and severe illness among US delivery hospitalisations with and without a coronavirus disease 2019 (COVID-19) diagnosis	USA	Cohort	6550+ vs. 482,921–	GDM: 706 (10.8%) vs. 44,554 (9.2%), *p < .0001; PIH: 350 (5.3%) vs. 31,787 (6.6%), *p < .0001; pre-eclampsia/eclampsia: 616 (9.4%) 33,078 (6.8%), *p < .0001; preterm labour with preterm delivery: 315 (4.8%) vs. 17,392 (3.6%), RR (95% CI): 1.3 (1.2–1.5); stillbirth: 63 (1.0%) vs. 3439 (0.7%), RR (95% CI): 1.4 (1.1–1.7); maternal mortality: 9 (0.1%) vs. 32 (0.0%), RR (95% CI): 20.7 (9.9–43.4)
4. Maria de Lourdes Benamor Teixeira	Maternal and neonatal outcomes of SARS-Cov-2 infection in a cohort of pregnant women with comorbid disorders	Brazil	Cohort	33+ vs. 82–	Preeclampsia: 2 (6.9%) vs. 13 (17.1%); preterm delivery: 7 (26.9%) vs. 10 (13.7%)
5. Masoumeh Abedzadeh- Kalahroudi	Maternal and neonatal outcomes of pregnant patients with COVID-19: a prospective cohort study	Iran	Cohort	56+ vs. 94–	Pre-eclampsia: 11 (19.8%) vs. 7 (7.4%), *p = .037; preterm: 19 (34.5%) vs. 12 (12.8%), *p = .003; PROM: 4 (7.3%) vs. 9 (9.6%); foetal distress: 9 (16.1%) vs. 4 (4.3%), *p = .016	LBW: 11 (20%) vs. 14 (14.9%); foetal or neonatal death: 2 (3.6%) vs. 0 (0%); NICU admission: 9 (16.4%) vs. 20 (21.3%)
6. Federica Di Guardo	Poor maternal–neonatal outcomes in pregnant patients with confirmed SARS-Cov-2 infection: analysis of 145 cases	Italy	Cohort	145	Preterm birth: 55 (38%); maternal mortality: 7 (5%)	Neonatal death: 9 (6%); vertical transmission: 7 (5%)
7. Mikael Norman	Association of maternal SARS-CoV-2 infection in pregnancy with neonatal outcomes	Sweden	Cohort	2323+ vs. 84,719–	GDM: 163 (7.0%) vs. 4331 (5.0%); preterm infants: 205/2323 (8.8%) vs. 4719/85,836 (5.5%); post term: 6/39 (15.4%) vs. 146/2042 (7.1%)	Admission for neonatal care: 271 (11.7%) vs. 7351 (8.4%); neonatal respiratory disorder: 2.8% vs. 2.0%; hyperbilirubinemia: 3.6% vs. 2.5%; mortality: 0.30% vs. 0.12%; hypoxic-ischemic encephalopathy stage 2–3 d: 3 (0.1%) vs. 82 (0.1%); neonatal convulsions: 6 (0.3%) vs. 173 (0.2%); severe brain injury: 1/38 (2.6%) vs. 45/675 (6.7%); RDS: 29 (1.2%) vs. 508 (0.5%); meconium aspiration: 3 (0.1%) vs. 117 (0.1%); SGA: 54 (2.4%) vs. 1864 (2.2%) LGA: 84 (3.7%) vs. 3144 (3.7%); SARS-CoV-2-positive: 21 (0.90%)
8. Sara Cruz Melguizo	Pregnancy outcomes and SARS-CoV-2 infection: the Spanish Obstetric Emergency Group Study	Spain	Cohort	1347+ vs. 1607–	GDM: 97/1309 (7.4%) vs. 136/1584 (8.6%); IUGR: 48/1290 (3.7%) vs. 44/1566 (2.8%); PIH: 50 (3.7%) vs. 55 (3.4%); threatened abortion: 41/1275 (3.2%) vs. 43/1545 (2.8%); PROM: 209 (15.5%) vs. 179 (11.1%), *p < .001; PPROM: 37 (2.8%) vs. 23 (1.4%), *p = .012; preterm: 149 (11.1%) vs. 94 (5.8%), *p < .001; abruptio placentae: 12 (0.9%) vs. 7 (0.4%); PPH: 61 (4.5%) vs. 86 (5.4%); severe pre-eclampsia: 28/69 (40.6%) vs. 10/64 (15.6%), *p = .001; moderate pre-eclampsia: 41/69 (59.4%) vs. 54/64 (84.4%), *p = .001; stillbirth: 10 (0.7%) vs. 3 (0.2%), *p = .023	Apgar 5 score <7: 20/1335 (1.5%) vs. 21/1597 (1.3%); NICU admission: 137 (10.2%) vs. 39 (2.4%), *p < .001; neonatal mortality: 6 (0.4%) vs. 2 (0.1)
9. Haley A. Steffen	SARS-CoV-2 infection during pregnancy in a rural Midwest all-delivery cohort and associated maternal and neonatal outcomes	USA_Iowa	Cohort	61+ vs. 939– (neonate: 65+/971–)	Diabetes (T1DM, T2DM, gestational): 8 (13.7%) vs. 147 (15.6%); PIH: 4 (6.6%) vs. 94 (10%); preeclampsia without severe features: 3 (4.9%) vs. 35 (3.7%); preeclampsia with severe features: 6 (9.8%) vs. 49 (5.2%); eclampsia: 0 vs. 1 (0.11%); PROM: 6 (9.8%) vs. 84 (8.9%); preterm labour: 3 (4.9%) vs. 74 (7.9%); antenatal hypertensive disease: 14 (23.0%) vs. 228 (24.3%); placental abruption: 1 (1.6%) vs. 20 (2.1%); chorioamnionitis: 2 (6.3%) vs. 30 (5.2%); morbidly adherent placenta: 0 vs. 1 (0.2%); pyelonephritis: 1 (1.6%) vs. 5 (0.5%); PPH: 14 (23%) vs. 153 (16.3%)	Malformations: 10 (15.4%) vs. 117 (12.1%); absence of live birth: 3 (4.6%) vs. 12 (1.2%); neonatal death: 0 vs. 10 (1%)
10. Asimenia Angelidou	Association of maternal perinatal SARS-CoV-2 infection with neonatal outcomes during the COVID-19 pandemic in Massachusetts	USA_ Massachusetts	Cohort	250/255 neonate	Preterm birth (<32 weeks) or VLBW (<1500 g): 6 (2.4%); preterm birth (<37 weeks) or LBW (<2500 g): 62 (24.3%)	SGA: 13 (5.1%); very preterm birth (<32 weeks) or VLBW (<1500 g): 6 (2.4%); preterm birth (<37 weeks) or LBW (<2500 g): 62 (24.3%); congenital anomalies: 12 (4.7%); hypoglycaemia: 14 (5.5%); encephalopathy: 4 (1.6%); SARS-CoV-2 positive: 5 (2.0%)
11. Sahar H Abdulghani	Consequences of SARS-CoV-2 disease on maternal, perinatal and neonatal outcomes: a retrospective observational cohort study	Saudi Arabia	Cohort	62 (48 asymptomatic/14 symptomatic)	Meconium-stained amniotic fluid: 10	LBW: 7; premature infants: 11; positive naso-pharyngeal swab: 1
12. Qingqing Luo	Characteristics and pregnancy outcomes of asymptomatic and symptomatic women with COVID-19: lessons from hospitals in Wuhan	China	Cohort	42 (16 asymptomatic/25 symptomatic)	PROM: 6; GDM: 4; PIH: 3; oligohydramnios: 2; polyhydramnios: 1; malpresentation: 1; placenta previa: 1; intrahepatic cholestasis of pregnancy: 1; postpartum fever: 5; premature delivery: 9	Positive nucleic acid testing of SARS-CoV-2: 1
13. Zahra Akbarian-Rad	Neonatal outcomes in pregnant women infected with COVID-19 in Babol, North of Iran: a retrospective study with short-term follow-up	Iran	Cohort	8	Preterm: 3	LBW: 1; need for resuscitation at birth: 1; respiratory distress: 2; feeding problem: 2; poor reflexes: 2
14. Chrissy Liu	Effect of SARS-CoV-2 infection on pregnancy outcomes in an inner-city Black patient population	USA	Cohort	56+ vs. 279–	PIH or preeclampsia: 8 (14.3%) vs. 34 (12.2%); GDM: 6 (10.7%) vs. 41 (14.7%); preterm 34 to 36 + 6 weeks: 5 (8.9%) vs. 24 (8.8%); early preterm < 34 weeks: 3 (5.4%) vs. 17 (6.2%); PPH ≥ 1000 cm^3: 7 (13.7%) vs. 36 (14.5%);
15. Mehmet Ozsurmeli	Clinical characteristics, maternal and neonatal outcomes of pregnant women with SARS-CoV-2 infection in Turkey	Turkey	Cohort	24	Maternal mortality: 1	NICU admission: 1; neonatal death: 1
16. Sindy C Moreno	Vertical transmission of COVID-19 to the neonate	USA	Cohort	19/21 newborn	Preterm delivery: 8 (38.1%); ≤34 weeks.: 2 (25%) ≤37 weeks: 6 (75%)	NICU admission: 13 (61.9%); TTN: 6 (28.6%); RDS: 1 (4.8%)
17. Mehmet Yekta Oncel	A multicenter study on epidemiological and clinical characteristics of 125 newborns born to women infected with COVID-19 by Turkish Neonatal Society	Turkey	Cohort	125	GDM: 7 (5.8%); preeclampsia: 6 (4.9%); hypertension: 2 (1.6) placenta previa: 1 (0.8%); maternal mortality: 6 (4.8%);	Prematurity: 33 (26.4%); LBW: 16 (12.8%); NICU admission: 108 (86.4%); neonatal mortality: 1 (0.8%); positive RT-PCR test: 4/12 (3.3%)
18. Citra NZ Mattar	Pregnancy outcomes in COVID-19: a prospective cohort study in Singapore	Singapore	Cohort	16	Spontaneous miscarriages: 2
19. Monica Cruz-Lemini	Obstetric outcomes of SARS-CoV-2 infection in asymptomatic pregnant women	Spain	Cohort	174+ vs. 430–	Threatened abortion: 9 (5.2%) vs. 10 (2.3%); high-risk for preeclampsia in 1st trimester: 6 (3.4%) vs. 24 (5.6%); foetal anomaly in first trimester: 1 (0.6%) vs. 2 (0·5%); foetal anomaly in anatomy scan: 1 (0.6%) vs. 8 (1.9%); preterm delivery: 13 (7.5%) vs. 28 (6.5%); stillbirth: 2 (1.1%) vs. 0.0 (0); PROM: 31 (17.8%) vs. 44 (10.2%), *p = .011; PPROM: 5 (2.9%) vs. 5 (1.2%); PIH: 11 (6.4%) vs. 24 (5.8%); preeclampsia 7 (4%) vs. 23 (5.4%); obstetric haemorrhage: 6 (3.4%) vs. 20 (4.7%)	NICU admission: 12 (6.9%) vs. 7 (1.6%), *p = .001
20. Sourabh Verma	Outcomes of maternal-newborn dyads after maternal SARS-CoV-2	USA-New York	Cohort	149	Premature delivery: 16 (11%); GDM: 10 (7%); PIH: 17 (11%); foetal distress: 8 (5%); meconium-stained amniotic fluids: 23 (15%)	NICU admission: 18 (12%); neonatal demise: 1 (1%); respiratory distress: 13/148 (9%); RT-PCR positive for SARS-CoV-2: 1/87 (1%)
21. Najeh Hcini	Maternal, foetal and neonatal outcomes of large series of SARS-CoV-2 positive pregnancies in peripartum period: a single-centre prospective comparative study	France	Cohort	137+ vs. 370–	Preeclampsia/hypertension during pregnancy: 15 (10.9%) vs. 31 (8.3%); premature labour: 7 (5.1%) vs. 16 (4.3%); spontaneous preterm delivery <37 + 0 weeks: 11 (8.7%) vs.36 (10.0%); spontaneous preterm delivery <34 + 0 weeks: 1 (0.8%) vs. 9 (2.6%); GDM: 13 (9.4%) vs. 30 (8.1%); extremely preterm infants (22–23 + 6WG): 0 (0.0%) vs. 6 (1.6%); IUFD (19–35 W G): 7 (5.1%) vs. 4 (1.1%), *p = .0057; IUFD (19–35 W G): 7 (5.1%) vs. 4 (1.1%), *p = .0057; termination of pregnancy for foetal abnormalities: 3 (2.2%) vs. 1 (0.3%); meconium-stained amniotic fluid: 8 (6.3%) vs. 30 (8.4%); PPH: 18 (14.2%) vs. 26 (7.2%), *p = .0193	SGA foetus/foetal growth restriction: 3 (2.1%) vs.6 (1.6%); Apgar score ≤$7\mathrm{ }\text{at}\mathrm{ }1\mathrm{ }\min :\mathrm{ }14\mathrm{ }(11\mathrm{\%})\mathrm{ }\mathrm{vs}.31\mathrm{ }(8.5\mathrm{\%})\mathrm{ }0.5;\text{Apgar score }\le$ 7 at 5 min 4: (3.1%) 12 vs. (3.2%); RDS: 4 (3.1%) vs. 16 (4.3%); NICU admission: 3 (2.3%) vs. 12 (3.2%); SARS-CoV-2 RT PCR: 4/29 (13.8%)
22. Sara C Handley	Changes in preterm birth phenotypes and stillbirth at 2 Philadelphia hospitals during the SARS-CoV-2 pandemic, March–June 2020	USA	Cohort	3007 vs. 5907 prepandemic	Spontaneous preterm birth: 135 (4.7%) vs. 315 (5.7%); stillbirth: 15 (0.50%) vs. 32 (0.54%)
23. Amihai Rottenstreich	Vaginal delivery in SARS-CoV-2-infected pregnant women in Israel: a multicenter prospective analysis	Israel	Cohort	52	Preterm <37 weeks: 17 (32.7%), preterm <34 weeks: 9 (17.3%); GDM: 6 (11.5%); Gestational hypertensive disorders: 7 (13.4%); HELLP syndrome 1 (1.9%); PPH: 6 (11.5%)	5-min Apgar score < 8: 1 (1.9%); NICU admission: 6 (11.5%); RDS: 6 (11.5%); TTN: 1 (1.9%); hypoglycaemia: 4 (9.3%); hyperbilirubinemia: 5 (9.6%)
24. Ifeoma Ogamba	Initial review of pregnancy and neonatal outcomes of pregnant women with COVID-19 infection	USA	Cohort	40	Preterm 34–37 weeks: 1 (4%), <34 weeks: 3 (12%); PPH: 2 (8%); second trimester foetal loss: 2 (8%)	Preterm delivery, apnoea of prematurity: 1; hyperbilirubinemia: 1
25. Marjolein F Husen	Unique severe COVID-19 placental signature independent of severity of clinical maternal symptoms	Netherlands	Cohort	36	GDM: 6 (16.7%); hypertensive disorders: 2 (5.6%); spontaneous preterm delivery: 1 (2.8%); foetal distress: 7 (19.4%)	SGA: 9 (23.1%); Apgar <7 at 5 min: 5 (12.8%); pH <7.10: 2 (5.1%); neonatal SARS-CoV-2 positive: (1/39) 1 (2.6%)
26. Maryam Vizheh	Characteristics and outcomes of COVID-19 pneumonia in pregnancy compared with infected nonpregnant women	Iran	Cohort	110 pregnant and 234 nonpregnant	Spontaneous abortion: 8 (7.3%); GDM: 5 (4.5%); pre-eclampsia: 5 (4.5%); foetal distress: 9 (22.5%); preterm labour: 13 (11.8%); PROM: 5 (4.54%)	LBW: 12 (10.9%); NICU admission: 15 (29.4%); respiratory complications: 7 (13.7%); neonatal death: 2 (3.9%); neonatal positive SARS-CoV-2 result: 8 (15.7%)
27. Abdulrahman Al-Matary	Clinical outcomes of maternal and neonate with COVID-19 infection – multicenter study in Saudi Arabia	Saudi Arabia	Cohort	288	Premature or preterm delivery: 31 (15.5%); PROM: 16 (8%); fatal distress: 13 (6.5%); preeclampsia: 4 (2.0%); maternal mortality: 1 (0.5%); foetal death: 4 (2.0); IUGR: 3 (1.5%)	LBW: 29 (14.5%); birth weight >4000 g: 1 (0.5%); 1-min Apgar score <5: 18 (9.0%); 5-min Apgar score <5: 5 (2.5%); NICU admission: 86 (43.0%)
28. Itzíar Carrasco	SARS-COV-2 infection in pregnant women and newborns in a Spanish cohort (GESNEO-COVID) during the first wave	Spain	Cohort	105/107 newborns	Preterm birth: 21 (20.6%)	SGA: 6 (5.61%); NICU admission: 18 (16.8%); RT-PCR at 15 days positive 1 (0.93%)
29. Torri D Metz	Disease severity and perinatal outcomes of pregnant patients with coronavirus disease 2019 (COVID-19)	USA	Cohort	1219	Maternal mortality: 6; PPH: 108; hypertensive disorders of pregnancy: 285; abortion: 13; foetal death: 10; spontaneous preterm birth: 75	SGA: 126; NICU admission: 254; neonatal death: 5
30. Edward Mullins	Pregnancy and neonatal outcomes of COVID-19: coreporting of common outcomes from PAN-COVID and AAP-SONPM registries	UK	Cohort	651	Maternal mortality: 3 (0.5%); miscarriage: 12/647 (1.9%); Intrauterine death/stillbirth: 4/647 (0.6%); preterm delivery (live births only): 100/622 (16.1%); spontaneous onset of preterm labour and vaginal delivery (live births only): 22/621 (3.5%)	Early neonatal death: 2/614 (0.3%); positive neonatal SARS-CoV-2: 13/131 (9.9%)
31. Virginia Engels Calvo	Perinatal outcomes of pregnancies resulting from assisted reproduction technology in SARS-CoV-2-infected women: a prospective observational study	Spain	Cohort	1347	Preterm deliveries: 148; PROM: 209; PPROM: 37; haemorrhagic events: 71; abruptio placentae: 12; PPH: 61; DIC: 4; gestational hypertensive disorders: 69; moderate preeclampsia: 41; severe preeclampsia: 28; stillbirth: 10; maternal mortality: 2 (0.15%)	Apgar 5 score <7: 13; NICU admission: 137; neonatal mortality: 6 (0.44%)
32. Justine Chinn	Characteristics and outcomes of women with COVID-19 giving birth at US academic centres during the COVID-19 pandemic	USA/California	Cohort	18,715+ vs. 850,364–	Preterm birth: 3072 (16.4%) vs. 97 967 (11.5%), *p < .001; maternal mortality: 24 (0.1%) vs. 71 (<0.01%), *p <.001
33. José Villar	Maternal and neonatal morbidity and mortality among pregnant women with and without COVID-19 infection: the INTERCOVID Multinational Cohort Study.	18 countries^a	Cohort	706+ vs. 1424–	Vaginal bleeding; 44 (6.2%) vs. 87 (6.1%); PIH: 58 (8.2%) vs. 80 (5.6%); preeclampsia/eclampsia/HELLP: 59 (8.4%) vs. 63 (4.4%); preterm labour: 52 (7.4%) vs. 88 (6.2%); maternal mortality: 11 (1.6%) vs. 1 (0.1%); foetal distress: 87 (12.3%) vs. 120 (8.4%); PROM: 114 (16.1%) vs. 262 (18.4%); spontaneous preterm birth: 27 (3.8%) vs. 66 (4.6%)	LBW: 145 (20.5%) vs. 181 (12.7%); SGA: 97 (13.7%) vs. 181 (12.7%)
34. Erica M Lokken	Disease severity, pregnancy outcomes and maternal deaths among pregnant patients with severe acute respiratory syndrome coronavirus 2 infection in Washington State	USA	Cohort	240	Maternal mortality: 3 (1.3%); stillbirth: 2 (1.3%); preterm birth: 15 (9.7%); GDM: 16 (10.3%); new-onset hypertensive disorder of pregnancy or postpartum: 19 (12.3%)	LBW: 7 (4.6%); NICU admission: 11 (7.1%)
35. Ann-Christin Tallarek	Inefficient placental virus replication and absence of neonatal cell-specific immunity upon SARS-CoV-2 infection during pregnancy	Germany	Cohort	42	Preterm delivery: 10 (24%); <34 weeks: 2 (5%)	NICU admission: 7 (17%)
36. Daniel Katz	The Society for Obstetric Anaesthesia and Perinatology Coronavirus Disease 2019 Registry: an analysis of outcomes among pregnant women delivering during the initial severe acute respiratory syndrome coronavirus-2 outbreak in the United States.	USA	Cohort	490+ vs. 964–	GDM: 33 (6.7%) vs. 67 (7.0%); hypertensive disorders of pregnancy: 75 (15.3%) vs. 123 (12.8%); preterm delivery: 72 (14.8%) vs. 98 (10.2%), *p = .011; placental abruption: 6 (1.2%) vs. 10 (1.0%); PPH > 500 mL for vaginal delivery: 35 (11.4%) vs. 66 (10.5%); PPH >1 L for caesarean delivery: 18 (10.8%), 40 (12.2%)	Neonatal composite outcome: 97 (19.6%) vs. 164 (16.5)
37. Francesco D'Antonio	Maternal and perinatal outcomes in high compared to low risk pregnancies complicated by severe acute respiratory syndrome coronavirus 2 infection (phase 2): the World Association of Perinatal Medicine Working Group on Coronavirus Disease 2019	25 countries in Europe, the United States, South America, Asia and Australia	Cohort	887	Preterm birth at <37 weeks: 94; preterm birth at <34 weeks: 41; miscarriage: 22; IUFD: 5	Neonatal death: 8; perinatal death: 13; NICU admission: 72
38. Fulvia Milena Cribiù	Severe SARS-CoV-2 placenta infection can impact neonatal outcome in the absence of vertical transmission	Italy	Cohort	21+/16–	GDM: 2 (10%) vs. 3 (19%); gestational cholestasis: 1 (5%) vs. 0(0%); IUGR: 0 (0%) vs. 1(6%); AF anomalies 2 (10%) vs. 0(0%); PROM: 2 (10%) vs. 2 (12%); PPROM: 1 (5%) vs. 1 (6%); foetal complications: 2 (10%) vs. 0 (0%); foetal malformation: 1 (5%) vs. 0 (0%); therapeutic miscarriage: 1 (5%) vs. 0 (0%); macrosomia: 0 (0%) vs. 1 (6%); suspected chorioamnionitis: 0(0%) vs. 0 (0%); premature delivery: 6 (29%) vs. 3(19%); foetal distress: 2 (10%) vs.4 (25%)
39. Hilde Engjom	COVID-19 in pregnancy – characteristics and outcomes of pregnant women admitted to hospital because of SARS-CoV-2 infection in the Nordic countries	Nordic countries (Denmark, Finland, Iceland, Norway, Sweden)	Cohort	48/51 infant	Preterm delivery: 12/48 (25%)	NICU admission: 7/51 (13.7%)
40. Enrico Ferrazzi	Vaginal delivery in SARS-cov-2-infected pregnant women in Northern Italy: a retrospective analysis	Italy	Cohort	42	GDM: 6 (14%); preterm birth: 11 (spontaneous preterm: 5; elective caesarean section: 6)	NICU admission: 3; positivity to SARS-Cov-2: 3
41. Noelle Breslin	COVID-19 infection among asymptomatic and symptomatic pregnant women: two weeks of confirmed presentations to an affiliated pair of New York City hospitals	USA New York	Cohort	43	Preterm labour (n = 1); PIH: 1; foetal distress: 3	NICU admission: 3
42. Ming-zhu Yin	Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy in China: a retrospective cohort study	China	Cohort	31	Premature delivery: 5/17	LBW: 1/17
43. Marian Knight	Characteristics and outcomes of pregnant women admitted to hospital with confirmed SARS-CoV-2 infection in UK: national population based cohort study	United Kingdom	Cohort	427	GDM: 50 (12%); maternal mortality: 5 (1%); pregnancy loss: 4 (1%); stillbirth: 3 (1%); preterm: 70	Neonatal death: 2 (1%); NICU admission: 67/267 (live born infants only) (25%); positive SARS-CoV-2 test (liveborn infants only): 12/256 (4.6%)
44. Rafael San-Juan	Incidence and clinical profiles of COVID-19 pneumonia in pregnant women: a single-centre cohort study from Spain	Spain	Cohort	32/6 delivery	Preterm: 2/6	LBW: 2 RDS: 1; intraventricular haemorrhage grade 1: 1
45. AM Rebecca Pierce-Williams	Clinical course of severe and critical COVID-19 in hospitalised pregnancies: a US cohort study.	USA	Cohort	64	Hypertensive disorders of pregnancy: 2 (3%); magnesium sulphate for preeclampsia: 1 (2%); IUGR: 2 (3%); oligohydramnios: 1 (2%); presumed chorioamnionitis or endometritis: 3 (9%); PPH: 3 (9%); preterm delivery at <37 weeks: 19 (59%); preterm delivery at <34 weeks: 10 (31%); spontaneous preterm labour: 2 (6%); PPROM: 1 (3%)	NICU admission: 21 (63.6%)
46. Viktoriya London	The relationship between status at presentation and outcomes among pregnant women with COVID-19	USA	Cohort	68/55 of the 68 have delivered	GDM: 7 (10.3%); cholestasis of pregnancy: 2 (2.9%); preterm birth <37 weeks: 9 (16.4%); preterm birth <34 weeks: 3 (5.5%); PPH: 2 (3.6%); preeclampsia: 4 (7.3%)	–
47. Rasha Khoury	Characteristics and outcomes of 241 births to women with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection at Five New York City Medical Centres.	USA	Cohort	241	Stillbirth: 2/247 (0.8%); singleton preterm birth (<37 weeks): 34/233 (14.6%); singleton early preterm birth (<34 weeks): 10/233 (4.3%); mal-presentation: 5/100 (5%)	Resuscitation at delivery: 70/233 (30.0%); NICU admission: 61/237 (25.7%); NRDS: 14/241 (5.8%); complications of prematurity or LBW: 21/241 (8.7%); sepsis: 1/241 (0.4%); congenital anomaly: 8/241 (3.3%); neonatal COVID-19 test result positive 6/236 (2.5%)
48. Valeria M Savasi	Clinical findings and disease severity in hospitalised pregnant women with coronavirus disease 2019 (COVID-19)	Italy	Cohort	77	Preterm delivery: 12 (21%)	NICU admission: 9 (16%); newborn COVID-19 test result, positive: 4 (7%)
49. Christine M Salvatore	Neonatal management and outcomes during the COVID-19 pandemic: an observation cohort study	USA	Cohort	116	Preterm (<37 weeks): 14; PROM: 96	LBW: 12 NICU admission: 12
50. Kate R Woodworth	Birth and infant outcomes following laboratory-confirmed SARS-CoV-2 infection in pregnancy – SET-NET, 16 jurisdictions, March 29–October 14, 2020	USA	Cohort	4442	PIH: 211 (7.6%); GDM: 228 (8.2%); pregnancy loss: 32 (0.7%); pregnancy loss <20 weeks: 12 (0.3%): pregnancy loss ≥20 weeks: 20 (0.4%): preterm (<37 weeks): 506 (12.9%); late preterm (34–36 weeks): 357 (9.1%); late preterm (34–36 weeks): 357 (9.1%); moderate preterm (32–33 weeks): 50 (1.3%); very preterm (28–31 weeks): 69 (1.8%); extremely preterm (<28 weeks): 30 (0.8%)	NICU admission among term live births: 279/2995 (9.3%); birth defects among live births: 28/4447 (0.6%)
51. Miranda J Delahoy	Characteristics and maternal and birth outcomes of hospitalised pregnant women with laboratory-confirmed COVID-19 – COVID-NET, 13 states, March 1–August 22, 2020	USA	Cohort	598	GDM: 64/581 (11.0%); hypertensive disorders of pregnancy: 70/581 (12.0%); IUGR: 11/581 (1.9%); pregnancy loss: 10/458 (2.2%); pregnancy loss at <20 weeks’ gestation: 4/458 (0.9%); pregnancy loss at ≥20 weeks’ gestation: 5/458 (1.1%); pregnancy loss at unknown gestational age 1/458 (0.2%); maternal mortality: 2/598 (0.3%)	Neonatal death: 2/448 (0.4%)
52. Claudio Fenizia	Analysis of SARS-CoV-2 vertical transmission during pregnancy	Italy	Cohort	31	Preterm delivery: 1 (3%)	NICU admission: 2 (6%); APGAR score 5′ <7: 1 (3%); infected neonates, positive: 2 (6%)
53. Dilek Sahin	Updated experience of a tertiary pandemic centre on 533 pregnant women with COVID‐19 infection: a prospective cohort study from Turkey.	Turkey	Cohort	533	Maternal mortality: 2 (0.4%); threatened abortion: 2 (0.3%); miscarriage: 12 (2.2%); hyperemesis gravidarum: 2 (0.3%); cholestasis of pregnancy: 5 (0.9%); foetal anomaly: 3 (0.5%); intrauterine foetal demise: 1 (0.2%); foetal growth restriction: 5 (0.9%); GDM: 3 (0.5%); PIH: 4 (0.7%); preterm delivery: 22 (4.1%); pre-eclampsia: 5 (0.9%); placental abruption: 1 (0.2%); deep vein thrombosis: 1 (0.2%); pregnancy loss: 13 (2.4%); foetal distress: 12 (13.8%)	Macrosomia 5 (5.7%); NICU admission: 13 (9.9%)
54. Jayasree Santhosh	Clinical characteristics of COVID‐19 in pregnant women: A retrospective descriptive single‐centre study from a tertiary hospital in Muscat, Oman	Oman	Cohort	60	Hypertension: 3 (5%); GDM: 15 (25%); preterm: 18 (30%); (late preterm delivery (34–36 + 6): 14 (24%); early preterm delivery (24–33 + 6): 4 (6.8%)); amniotic fluid, meconium stain (7/47): 7 (15%); PPROM: 1 (2.0%); preeclampsia: 4 (6.7%); preterm labour: 8 (16%); PPH: 2 (3.3%); pulmonary embolism: 2 (3.3%); pelvic haematoma: 1 (2.0%); miscarriage: 4 (6.7%); macerated stillbirth (47/60): 1 (2.1%)	LBW <2500 g (47/60) 15 (32%)
55. Mahtab Sattari	Evaluating clinical course and risk factors of infection and demographic characteristics of pregnant women with COVID-19 in Hamadan Province, West of Iran.	Iran	Cohort	50/26 have not given birth yet	Maternal mortality: 2 (4%); preterm delivery: 7 (29.2%)	Infection of the newborn according to Covid-19: 7 (28%)
56. Yan-Ting Wu	Neonatal outcome in 29 pregnant women with COVID-19: a retrospective study in Wuhan, China	China	Cohort	29/30 newborn	Gestational hypertensive disorder: 2 (6.90%); GDM: 3 (10.34%); gestational anaemia: 3 (10.34%); PPROM: 5 (17.24%); foetal distress: 3 (10.34%); preterm: 3 (10.34%)	COVID-19 diagnosis 2 confirmed and 3 suspected
57. Laura D Zambrano	Update: characteristics of symptomatic women of reproductive age with laboratory-confirmed SARS-CoV-2 infection by pregnancy status – United States, January 22–October 3, 2020	USA	Cohort	23,434	Maternal mortality: 34 (1.5%) (a total of 5152 (22.0%) pregnant women and 66,346 (17.2%) nonpregnant women were missing information on death and were assumed to have survived)
58. Malavika Prabhu	Pregnancy and postpartum outcomes in a universally tested population for SARS‐CoV‐2 in New York City: a prospective cohort study	USA	Cohort	70/73 newborn	Pre-eclampsia or PIH: 11; GDM: 6; preterm birth <37 weeks: 11; malpresentation: 1; Intrapartum fever: 7; PPH >1000 mL: 3; postpartum fever: 8	NICU admission: 13 (17.8%)
59. Amanda Dhuyvetter	Coronavirus disease 2019 in pregnancy: the experience at an urban safety net hospital	USA	Cohort	23	GDM: 1 (4.3%);PIH: 2 (8.7%); cholestasis of pregnancy: 2 (8.7%)	SGA: 1 (4.3%)
60. Mohsen AA Farghaly	Characteristics of newborns born to SARS-CoV-2-positive mothers: a retrospective cohort study	USA	Cohort	15	Preterm: 2 (13.3%)	NICU admission: 10 (66.7%); nursery admission: 5 (33.3%)
61. Mónica Ríos-Silva (Silva et al. 2020)	COVID-19 mortality among pregnant women in Mexico: a retrospective cohort study	Mexico	Cohort	448	Maternal mortality: 10 (2.2%)
62. Niyazi Tug	Pregnancy worsens the morbidity of COVID-19 and this effect becomes more prominent as pregnancy advances	Turkey	Cohort	188	Extremely preterm: 1/60 (1.7%), very preterm: 2/60 (3.3%), moderate/late preterm: 11/60 (18.3%); preeclampsia: 6 (3.2%); GDM: 1; placenta previa: 1
63. Rong Yang	Pregnant women with COVID-19 and risk of adverse birth outcomes and maternal–foetal vertical transmission: a population-based cohort study in Wuhan, China	China	Cohort	65	PIH: 3 (5%); preeclampsia: 1 (1%); GDM: 3 (5%); PROM: 4 (6%); preterm birth: 9 (14%)
64. Wei Liu	Clinical analysis of neonates born to mothers with or without COVID-19: a retrospective analysis of 48 cases from two neonatal intensive care units in Hubei Province	China	Cohort	15	Hypertensive disorders: 2 (13.3%); GDM: 2 (13.3%); chorioamnionitis: 2 (13.3%); PPH: 1 (6.7%)
65. Puneet Gupta	SARS-CoV-2 prevalence and maternal–perinatal outcomes among pregnant women admitted for delivery: experience from COVID-19-dedicated maternity hospital in Jammu, Jammu and Kashmir (India)	India	Cohort	108+ vs. 3057–	Preterm: 31 (28.3%) vs. (14.6%)*; maternal mortality: 1 (0.9%) vs. 7 (0.22%); GDM: 16 (14.8%) vs. 334 (10.9%); PIH: 12 (11.1%) vs. 264 (7.39%); intrahepatic cholestasis: 10 (9.2%) vs. 212 (6.93%); antepartum haemorrhage: 6 (5.55%) vs. 132 (4.3%); PPH: 5 (4.6%) vs. 110 (3.59%); foetal distress: 24 (22.2%) vs. 334 (10.9%), *p < .001	Birth weight, *p < .0001; NICU admission: 14 (12.9%) vs. 254 (8.3%); neonatal deaths: 2 (1.9%) vs. 42 (1.3)
66. Adhikari	Pregnancy outcomes among women with and without severe acute respiratory syndrome coronavirus 2 infection	USA	Cohort	252 SARS-CoV-2-positive and 3122 negatives	Abortion: 7 (3%) vs. 87 (3%); GDM: 14 (6%) vs. 207 (7%); severe preeclampsia: 26 (11%) vs. 359 (12%); abruption: 0 (0.0%) vs. 24 (1%); clinical chorioamnionitis: 24 (10%) vs. 345 (11%); stillbirth: 0 (0%) vs. 18 (0.6%); excessive blood loss (haemorrhage): 17 (7%) vs. 278 (9%); meconium-stained amniotic fluid: 53 (22%) vs. 571 (19%)	SGA: 31 (13%) vs. 316 (10%); 5-min Apgar score <4: 0 (0%) vs. 37 (1.2%); umbilical cord blood pH <7.0 d: 1 (0.4%) vs. 9 (0.3%); positive infants: 6
67. Milbak	A prospective cohort study of confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy evaluating SARS-CoV-2 antibodies in maternal and umbilical cord blood and SARS-CoV-2 in vaginal swabs	Denmark	Cohort	28 pregnant women with SARS‐CoV‐2 infection	PIH: 1 (3.6%); deep venous thrombosis: 1 (3.6%); pulmonary embolism: 1 (3.6%); GDM: 2 (7.1%); preterm delivery (<37 + 0 weeks): 2 (7.1%)	Apgar (5 min) <7: 1 (3.6%); NICU: 3 (10.7%); neonatal death: 1 (3.6%)
68. Ward	The clinical impact of maternal COVID-19 on mothers, their infants, and placentas with an analysis of vertical transfer of maternal SARS-CoV-2-specific IgG antibodies	USA	Cohort	115 mothers with SARS-CoV-2	PIH: 16 (13.9%); GDM: 11 (9.57%); meconium: 16 (13.9%); chorioamnionitis: 7 (6.09%); PPROM/PROM: 3 (2.61%); IUGR: 4 (3.48%); nuchal chord: 13 (11.3%); haemorrhage: 14 (12.2%); foetal intolerance: 14 (12.2%); failure to progress: 9 (7.83%); preeclampsia/HELLP syndrome: 15 (13.0%); preterm labour: 1 (0.87%); abruptio placenta: 1 (0.87%); retained placenta: 1 (0.87%); oligohydramnios: 1 (0.87%); shoulder dystocia: 1 (0.87%)	NICU/PICU admission: 23 (20.0%); premature (<37 weeks): 14 (12.2%); LGA: 8 (6.96%); SGA: 4 (3.48%); newborns tested for SARS-CoV-2 positive: 1 (1.47%)
69. Péju	Management and outcomes of pregnant women admitted to intensive care unit for severe pneumonia related to SARS-CoV-2 infection: the multicenter and international COVIDPREG study	France	Cohort	187 pregnant women with COVID-19	Abortion: 4; PIH: 10; GDM: 48; preeclampsia: 8; mortality: 2; PPH: 11; stillbirth: 3; preterm birth (<32 weeks’ gestation): 47; preterm birth (<37 weeks’ gestation): 79	Foetal or neonatal mortality: 8; SGA: 9
70. Seyed- Abdolvahab Taghavi	Obstetric, maternal and neonatal outcomes in COVID-19 compared to healthy pregnant women in Iran: a retrospective, case-control study	Iran	Case-control	Case = 55/control = 55	GDM: 4 (7.27) vs. 2 (3.63); PIH: 2 (3.63) vs. 1 (1.81); abortion <21 weeks: 3/14 (21.42) vs. 2/14 (14.28); IUFD: 0 vs. 1/20 (5); PPH: 1/20 (5) vs. 3/20 (15); preterm birth: 5/20 (25) vs. 2/20 (10), *p value <.05; foetal distress: 2/20 (10) vs. 1/20 (5)	LBW: 2/20 (10) vs. 1/20 (5); Apgar in 5 min <7: 3/20 (15) vs.4/20 (20); respiratory distress: 3/20 (15) vs. 1/20 (5); NICU admission: 2/20 (10) vs. 3/20 (15), neonatal dead: 1/20 (5) vs. 0
71. Justin S. Brandt	Epidemiology of coronavirus disease 2019 in pregnancy: risk factors and associations with adverse maternal and neonatal outcomes	USA	Case-control	61 cases/122 controls	Preterm delivery: <37 weeks: 7 (11.5%) vs.10 (8.2%); <34 weeks: 4 (6.6%) vs. 4 (3.3%); <28 weeks: 2 (3.3%) vs. 1 (0.8%); chorioamnionitis: 2 (3.3%) vs. 2 (1.6%); preeclampsia: 6 (9.8%) vs. 10 (8.2%)	NICU admission: 53 (86.9%) vs. 14 (11.5%); RDS: 5 (8.2%) vs. 6 (4.9%); intraventricular haemorrhage: 2 (3.3%) vs. 1 (0.8%); neonatal death: 1 (1.6%) vs. 1 (0.8)
72. MP Tadas	Maternal and neonatal outcomes of pregnant women with covid-19: a case-control study at a tertiary care centre in India	India	Case-control	181 vs. 181	Pregnancy morbidity: 100 (55.24%) vs. 54, *p = .000; stillbirth: 7 vs. 7	NICU admission: 14 vs. 16; neonatal death: 1 vs. 3
73. Na Li	Maternal and neonatal outcomes of pregnant women with COVID-19 pneumonia: a case-control study	China	Case-control	Confirmed (n = 16); suspected (n = 18)/control 2020 (n = 121) Control 2019 (n = 121)	Preeclampsia: 1; PIH: 3; GDM: 3; hypothyroidism: 2; PROM: 1; placental abruption: 1 in 16 confirmed cases; preterm delivery: 3 (18.8%), 3 (16.7%) vs. 7 (5.8%), 6 (5.0%); intrauterine foetal distress: 2 (11.7%), 1 (5.3%) vs.6 (5.0%) and 6 (5.0%) in confirmed case, suspected case vs. control 2020 and 2019, respectively	Premature birth: 4 (23.5%), 4 (21.1%) 7 vs. (5.8%) and 6 (5.0%); low birth weight: 3 (17.6%), 2 (10.5%) vs. 3 (2.5%) and 3 (2.5%) in confirmed case, suspected case vs. control 2020 and 2019, respectively
74. Guoqiang Sun	Blood test results of pregnant COVID-19 patients: an updated case-control study	China	Case-control	60	Preterm: 10 (16.67)

GDM: gestational diabetes mellitus; PIH: pregnancy-induced hypertension (gestational hypertension); PP/PA: placenta previa/accrete; IUGR: intrauterine growth restriction; AF: amniotic fluid; PROM: premature rupture of membrane; PPROM: preterm premature rupture of membrane; PPH: postpartum haemorrhage; NRDS: neonatal respiratory distress syndrome; GTT: glucose tolerance test; HELLP: haemolysis elevated liver enzymes, and low platelets; RDS: respiratory distress syndrome; TTN: transient tachypnoea of the newborn; HELLP: haemolysis elevated liver enzymes, and low platelets; DIC: disseminated intravascular coagulation.

*Statistically significant differences p < .05.

^aArgentina, Brazil, Egypt, France, Ghana, India, Indonesia, Italy, Japan, Mexico, Nigeria, North Macedonia, Pakistan, Russia, Spain, Switzerland, UK and the US.

Table 2. Results of the meta-regression using income level of countries (according to the World Bank classification).

Outcome	High income (reference)	Lower middle income		Upper middle income
	Coefficient	Coefficient (95% CI)	p Value	Coefficient (95% CI)	p Value
GDM	1	–0.63 (–1.59, 0.32)	.195	–0.26 (–0.73, 0.21)	.258
Hypertensive disorders	1	–0.91 (–2.45, 0.63)	.248	–0.31 (–0.74, 0.12)	.163
IUGR/SGA^a	1	–	–	–1.42 (–3.26, 0.41)	.129
LBW	1	–0.30 (–1.38, 0.78)	.583	0.08 (–1.01, 1.17)	.891
Maternal mortality	1	1.82 (–0.82, 4.45)	.176	1.59 (–0.03, 3.21)	.054
Neonatal death	1	1.30 (–0.42, 3.02)	.138	1.25 (–0.49, 2.99)	.160
NICU admission	1	–0.36 (–1.57, 0.84)	.553	–0.08 (–1.09, 0.93)	.875
PPH	1	–1.30 (–2.35, −0.24)	.016	–0.67 (–1.49, 0.15)	.109
Pregnancy loss	1	1.23 (0.48, 1.98)	.001	1.27 (0.11, 2.41)	.030
Preterm delivery	1	0.01 (–0.88, 0.91)	.974	–0.02 (–0.55, 0.51)	.93
PROM	1	–0.29 (–1.98, 1.40)	.736	–0.44 (–1.44, 0.55)	.384
SARS-CoV2 positive neonates	1	1.04 (0.26, 1.81)	.009	0.30 (–0.58, 1.19)	.504

^aThere was no sample for the lower middle-income countries.

Silva, C.R.A.C.D., et al., 2020. Immunological aspects of coronavirus disease during pregnancy: an integrative review. Revista da Associacao Medica Brasileira (1992), 66 (5), 696–700.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information. The datasets generated during and/or analysed during the current study are available from the corresponding author upon reasonable request.