Study characteristics
| Data source | Study | Location | Dates of data collection | Recruitment strategy* | COVID-19 case definition | COVID-negative comparison group | ||||
| Prospective pregnancy cohort studies | Akelo and Tippett Barr (2021) | Kenya | July 2020 to May 2021, with follow-up through delivery | a | b | c | d | e | Positive PCR test | Negative PCR test |
| Le Doare (2021) | Uganda | September 2020 to July 2021, with follow-up through delivery | a | b | c | Positive PCR or diagnosed probable COVID-19 | Negative PCR or antibody test (recruitment) | |||
| Crovetto (2020), Cohort I | Spain | March to May 2020, with follow-up through delivery | a | b | Positive PCR or antibody test† | Negative antibody test (ANC) and negative PCR test (delivery) | ||||
| Other cohort studies | Poon (2021) | China-Hong Kong | March 2020 to January 2021 | a | b | c | d | e | Positive PCR test or antibody test | Negative antibody test (ANC and delivery) |
| Crovetto (2020), Cohort II | Spain | March to May 2020 | b | Positive PCR or antibody test‡ | Negative antibody test and PCR test (delivery) | |||||
| Bevilacqua and Laurita Longo (2020) | Italy | February 2020 to March 2021 | b | c | d | e | Positive PCR test | Negative PCR test | ||
| Nachega (2021) | Africa§ (6 countries) | March to October 2020 | c | e | Positive PCR test | Negative PCR (hospital controls) | ||||
| Nunes (2021) | South Africa | April to September 2020 | a¶ | c | d | e | Positive PCR test | Negative PCR test | ||
| Sakowicz (2021) | Chicago, USA | March 2020 to February 2021 | b | d | e | Positive PCR test | Negative PCR test (at delivery) | |||
| Ahlberg et al 19 | Sweden | March to July 2020 | b | d | Positive PCR test or antibody test | Negative PCR test (at delivery) | ||||
| Kalafat et al 22 | Turkey | May to June 2020 | b | d | Positive PCR test | Negative PCR test | ||||
| Brandt (2020) | New Brunswick, USA | March to June 2020 | b | d | Positive PCR test | Negative PCR test | ||||
*Recruitment strategies categorised as: (a) universal screening at antenatal care, (b) universal screening at delivery, (c) hospitalised for COVID-19, (d) other COVID-19 testing for clinical concern, (e) tested based on admission for other medical reasons.
†Antibody tests were administered to women recruited at first trimester or early second trimester ANC. Participants were also administered follow-up PCR tests at labour and delivery.
‡Antibody tests were administered to all participating women at labour and delivery; most participants (85%) also received a PCR test at labour and delivery.
§Democratic Republic of Congo, Ghana, Kenya, Nigeria, South Africa, Uganda.
¶10 asymptomatic patients were tested a day during the recruitment period.
ANC, antenatal care.