1Department of Obstetrics and Gynecology, Isala Hospital, Zwolle, the Netherlands
2Department of Obstetrics and Gynecology, Maastricht University Medical Center, Maastricht, the Netherlands
3GROW, School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht, the Netherlands
Reprint requests to: Arnold-Jan Kruse, MD, PhD, Department of Obstetrics and Gynecology, Isala Clinics, PO Box 10400, 8000 GK Zwolle, the Netherlands. E-mail: [email protected]
Declaration of Interest: The e-Nose Company (Zutphen, the Netherlands) supplied an Aeonose, including software packages, filters, and mouthpieces, free of charge. Medical Specialists Company Isala (MSB Isala) invested in the eNose Company. AJK, NML, HHh, HWE, and MJ are members of MSB. The other authors have declared they have no conflicts of interest.
Ethics approval and data management: Regulatory approval was obtained from the institutional review board at Isala Clinics to undertake the study (June 29, 2020/registration number: 200626). All women provided written informed consent to participate.