The COPE study recruited participants from June 2020 to December 2022. All Swedish university hospitals and most smaller hospitals participated in recruitment (26 out of 42 delivery units). More than 2,800 women and 1,000 partners agreed to participate.

COPE includes a 1) biobank, 2) register-based health data, and 3) questionnaire based follow up. Only university hospitals and some smaller hospitals recruited to the biobank part. Participants could choose to join the biobank- and/or questionnaire part. A total of 2,436 birthing mothers participated in the questionnaire part, while 1,996 birthing mothers chose to contribute to the biobank part, and 1,551 birthing mothers participated in both parts. Additionally, 1,001 partners chose to participate in the questionnaire part.

1) Biosamples

Biosamples are stored at Biobank Sweden>>

Samples were collected according to a “screening group protocol” for women without a positive SARS-CoV-2 test during pregnancy and according to a more extensive “COVID-19 protocol” for women with a positive SARS-CoV-2 test during pregnancy. Some women in the screening group were sampled according to the COVID-19 protocol as controls.

Time points and type of biological sampling are presented in Figure 1.

The following analyses have been performed so far:

When working with material collected within the COPE study, all results from analyses of biological samples are made available within the COPE database.

2) Register-based data

Through linkage with the Swedish citizens personal identification number, relevant information from the following registers has been linked to the study participants:

3) Questionnaires

COPE participants received electronic questionnaires based on validated instruments as well as COPE specific questions and free text options at several time points from inclusion until four years after delivery – data collection is still ongoing.