Parvanov, Dimitar http://orcid.org/0000-0003-4992-002X
Ganeva, Rumiana
Vidolova, Nina
Stamenov, Georgi
Article History
Received: 8 January 2021
Accepted: 29 March 2021
First Online: 5 April 2021
Declarations
: The protocol of the study and the informed consent forms have been approved by the IRB committee of the Nadezhda Women’s Health Hospital and conform to the ethical principles of the Declaration of Helsinki for medical research involving human subjects.
: The authors declare no competing interests.