Vousden 2021.

Study characteristics
Notes	English title The incidence, characteristics and outcomes of pregnant women hospitalized with symptomatic and asymptomatic SARS‐CoV‐2 infection in the UK from March to September 2020: a national cohort study using the UK Obstetric Surveillance System (UKOSS) (preprint) Study setting Start of study recruitment (MM/YYYY): 03/2020 End of study recruitment (MM/YYYY): 08/2020 Study design: Prospective cohort Study centre(s): Multiple centres/clinics/areas within a country Number of centres, clinics or areas: 194 Study setting: Inpatient Number of participants recruited: 1148 (cohort 1), 722 (cohort 2), 426 (cohort 3) Sampling method: Consecutive participants Participants Female participants (absolute number): 2296 Age measure, value: Median (IQR), NR Inclusion criteria: Women who were hospitalised from 1st March 2020 to 31st August 2020. Hospital admission was defined as a hospital stay of 24 hours or longer for any cause, or admission of any duration to give birth. Women were taken as confirmed SARS‐CoV‐2 if they were hospitalised during pregnancy or within two days of giving birth and had a positive test during or within seven days of admission, or they were symptomatic and had evidence of pneumonia on imaging which was typical of SARS‐CoV‐2. Exclusion criteria: Women were excluded if they did not meet this case definition. Smoking frequency: 99 (cohort 1), 42 (cohort 2), 57 (cohort 3) Diabetes frequency: 28 (cohort 1), 22 (cohort 2), 6 (cohort 3) Hypertension frequency: 26 (cohort 1), 24 (cohort 2), 2 (cohort 3) Cardiovascular disease frequency: 21 (cohort 1), 13 (cohort 2), 8 (cohort 3) Asthma frequency: 77 (cohort 1), 49 (cohort 2), 28 (cohort 3) Chronic obstructive pulmonary disease frequency: NR Other pulmonary disease frequency: NR Immunosuppression frequency: NR Chronic kidney disease frequency: NR Cancer frequency: NR Steroid administration frequency: NR Supplemental oxygen administration frequency: NR Other treatments (frequency): NR Prognostic factor(s) Study’s definition for obesity: NR The time when obesity has been measured: NR Main variable used for determination of obesity: BMI Threshold used for definition: NR Obesity frequency (absolute number): 345 (cohort 1), 235 (cohort 2), 110 (cohort 3) Prognostic factor(s): Overweight   Obese Outcome(s) Hospitalisation  Outcome (prognostic factor) Hospitalisation (overweight) (cohort 1)  Follow‐up Number of patients followed completely for the outcome: 1148 Number of obese patients followed completely for the outcome: 345 Number of non‐obese patients followed completely for the outcome: 757 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.58 (1.26, 1.99), NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Any previous medical problem, BMI, ethnicity, smoking Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.52 (1.18, 1.95), NR Outcome (prognostic factor) Hospitalisation (obese) (cohort 1)  Follow‐up Number of patients followed completely for the outcome: 1148 Number of obese patients followed completely for the outcome: 345 Number of non‐obese patients followed completely for the outcome: 757 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.83 (1.45, 2.33), NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Any previous medical problem, BMI, ethnicity, smoking Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.75 (1.33, 2.27), NR Outcome (prognostic factor) Hospitalisation (overweight) (cohort 2)  Follow‐up Number of patients followed completely for the outcome: 722 Number of obese patients followed completely for the outcome: 235 Number of non‐obese patients followed completely for the outcome: 458 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 2 (1.54, 2.58), NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Any previous medical problem, BMI, ethnicity, smoking Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.86 (1.39, 2.48), NR Outcome (prognostic factor) Hospitalisation (obese) (cohort 2)  Follow‐up Number of patients followed completely for the outcome: 722 Number of obese patients followed completely for the outcome: 235 Number of non‐obese patients followed completely for the outcome: 458 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 2.31 (1.77, 3.01), NR Multivariable analysis for obesity Modelling method: Logistic regression The set of prognostic factors used for adjustment: Any previous medical problem, BMI, ethnicity, smoking Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 2.07 (1.53, 2.79), NR Outcome (prognostic factor) Hospitalisation (overweight) (cohort 3)  Follow‐up Number of patients followed completely for the outcome: 426 Number of obese patients followed completely for the outcome: 110 Number of non‐obese patients followed completely for the outcome: 299 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.1 (1.27, 1.48), NR Multivariable analysis for obesity Modelling method: NR The set of prognostic factors used for adjustment: NR Effect measure for obesity: NR Effect measure value (95% CI), P value: 1.52 (1.18, 1.95), NR Outcome (prognostic factor) Hospitalisation (obese) (cohort 3)  Follow‐up Number of patients followed completely for the outcome: 426 Number of obese patients followed completely for the outcome: 110 Number of non‐obese patients followed completely for the outcome: 299 Univariable unadjusted analysis for obesity Effect measure for obesity: Odds ratio Effect measure value (95% CI), P value: 1.27 (0.94, 1.72), NR Multivariable analysis for obesity Modelling method: NR The set of prognostic factors used for adjustment: NR Effect measure for obesity: NR Effect measure value (95% CI), P value: NR
Item	Authors' judgement	Support for judgement
Study Participation	No	Appendix 3
Study Attrition Hospitalisation	Unclear	Appendix 3
Prognostic Factor Measurement	No	Appendix 3
Outcome Measurement Hospitalisation	Yes	Appendix 3
Confounding Bias Hospitalisation	Unclear	Appendix 3
Statistical Analysis Bias	No	Appendix 3