About the Authors

Y. H. M. Krul-Poel

Roles Formal analysis, Methodology, Writing – original draft

s.simsek@nwz.nl (SS); y.krul@vumc.nl (YKP)

Affiliation Department of Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, The Netherlands

P. P. Koenders

Roles Formal analysis, Writing – review & editing

Affiliation Department of Internal Medicine, Medical Center Alkmaar, Alkmaar, The Netherlands

R. P. Steegers-Theunissen

Roles Funding acquisition, Writing – review & editing

Affiliations Department of Pediatrics, Division of Neonatology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands, Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands

E. ten Boekel

Roles Writing – review & editing

Affiliation Department of Clinical Chemistry, Hematology & Immunology, Medical Center Alkmaar, Alkmaar, The Netherlands

M. M. ter Wee

Roles Methodology, Writing – review & editing

Affiliation Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, the Netherlands

Y. Louwers

Roles Writing – review & editing

Affiliation Department of Obstetrics and Gynecology, Erasmus MC, University Medical Center, Rotterdam, The Netherlands

P. Lips

Roles Writing – review & editing

Affiliation Department of Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, The Netherlands

J. S. E. Laven

Contributed equally to this work with: J. S. E. Laven, S. Simsek

Roles Conceptualization, Funding acquisition, Methodology, Writing – review & editing

Affiliation Division of Reproductive Medicine, Department of Obstetrics, Gynecology, Erasmus Medical Center Rotterdam, The Netherlands

S. Simsek

Contributed equally to this work with: J. S. E. Laven, S. Simsek

Roles Conceptualization, Funding acquisition, Methodology, Supervision, Writing – review & editing

s.simsek@nwz.nl (SS); y.krul@vumc.nl (YKP)

Affiliations Department of Internal Medicine/Endocrinology, VU University Medical Center, Amsterdam, The Netherlands, Department of Internal Medicine, Medical Center Alkmaar, Alkmaar, The Netherlands

Competing Interests

JSE has received research grants from the following pharmaceutical companies (in alphabetical order): Ferring, Merck Serono, Merck Sharpe and Dome, Organon, Shering Plough and Serono. This does not alter our adherence to PLOS ONE policies on sharing data and materials.