1 Department of Clinical Sciences, Obstetrics and Gynecology, Umeå University, Umeå, Sweden
2 Dalarna University, School of Health and Social Studies, Falun, Sweden
3 Umeå School of Business and Economics, Department of Statistics, Umeå University, Umeå, Sweden
4 Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Stockholm, Sweden
5 Primary Health Care, Parental and Child Health Care, Östersund, Sweden
6 Department of Research and Development, Västernorrland County Council, Sundsvall, Sweden
7 Primary Health Care, Maternal Health Care Unit, Örebro, Sweden