Received: 25 June 2019
Accepted: 17 May 2020
First Online: 26 May 2020
Ethics approval and consent to participate
: No ethnical approval was needed according to the Dutch central committee of Human Research (involving Human Subjects) Act, as the study used only previously collected data / retrospective cohort study. (“Wet Medisch-Wetenschappelijk Onderzoek met Mensen, 1998 §1 Article 1”). For this paper only pseudo anonymised data were processed.The science/ethical committee of the Netherland Perinatal Registry (PERINED) provided permission for data analysis trend in perinatal mortality and the intermediate risks groups (16.13).
: Not applicable.
: The authors AR, ME, JAMP, AAH, and CJMdG declare that they have no conflict of interest.