Supplementary Material for: Infants Born to Mothers Who Were SARS-CoV-2 Positive during Pregnancy and Admitted to Neonatal Intensive Care Unit

<b><i>Introduction:</i></b> Our objective was to compare neonatal outcomes and resource use of neonates born to mothers with SARS-CoV-2 positivity during pregnancy with neonates born to mothers without SARS-CoV-2 positivity. <b><i>Methods:</i></b> We conducted a two-country cohort study of neonates admitted between January 1, 2020, and September 15, 2021, to tertiary neonatal intensive care unit (NICU) in Canada and Sweden. Neonates from mothers who were SARS-CoV-2 positive during pregnancy were compared with three randomly selected NICU neonates of mothers who were not test-positive, matched on gestational age, sex, and birth weight (±0.25 SD). Subgroup analyses were conducted for neonates born &lt;33 weeks’ gestation and mothers who were SARS-CoV-2 positive ≤10 days prior to birth. Primary outcome was duration of respiratory support. Secondary outcomes were in-hospital mortality, neonatal morbidity, late-onset sepsis, receipt of breast milk at discharge, and length of stay. <b><i>Results:</i></b> There were 163 exposed and 468 matched neonates in Canada, and 303 exposed and 903 matched neonates in Sweden. There was no statistically significant difference in invasive or noninvasive respiratory support durations, mortality, respiratory and other neonatal morbidities, or resource utilizations between two groups in both countries in entire cohort and in subgroup analyses. Receipt of breast milk at discharge was lower in the Canadian neonates of mothers who were SARS-CoV-2 positive ≤10 days before birth (risk ratio 0.68, 95% CI: 0.57–0.82). <b><i>Conclusion:</i></b> Maternal SARS-CoV-2 positivity was not associated with increased durations of respiratory support, morbidities, mortality, or length of hospital stay in Canada and Sweden among neonates admitted to tertiary NICU.

引言：本研究旨在对比妊娠期间严重急性呼吸综合征冠状病毒2（SARS-CoV-2）检测阳性母亲所娩新生儿，与SARS-CoV-2检测阴性母亲所娩新生儿的新生儿结局及医疗资源消耗情况。
方法：本研究为一项双国家队列研究，纳入2020年1月1日至2021年9月15日期间，入住加拿大与瑞典三级新生儿重症监护病房（NICU）的新生儿。将妊娠期间SARS-CoV-2检测阳性母亲所娩新生儿，与按胎龄、性别及出生体重（±0.25倍标准差）匹配的3名SARS-CoV-2检测阴性母亲所娩NICU新生儿进行对照。本研究针对胎龄＜33周的新生儿，以及分娩前≤10天SARS-CoV-2检测阳性的母亲开展亚组分析。本研究的主要结局为呼吸支持时长；次要结局包括住院死亡率、新生儿并发症、晚发性败血症、出院时母乳喂养率，以及住院时长。
结果：加拿大队列中共纳入163例暴露组新生儿与468例匹配对照新生儿，瑞典队列则有303例暴露组与903例匹配对照新生儿。在全队列及亚组分析中，两国的两组新生儿在有创与无创呼吸支持时长、死亡率、呼吸系统及其他新生儿并发症、医疗资源利用情况等方面，均未观察到统计学显著性差异。在分娩前≤10天SARS-CoV-2检测阳性的加拿大产妇所娩新生儿中，出院时母乳喂养率更低（风险比0.68，95%置信区间：0.57~0.82）。
结论：针对加拿大与瑞典三级NICU收治的新生儿，母亲妊娠期间SARS-CoV-2检测阳性，与新生儿呼吸支持时长延长、并发症发生率升高、死亡率增加或住院时长延长均无显著关联。