Introduction: In adults, olfactory loss is one of the earliest and most frequent acute clinical manifestations of SARS-CoV-2 infection. The number of children infected with SARS-CoV-2 is relatively small, perhaps due to the lower expression of Angiotensin Converting Enzyme 2 (ACE2) in children compared to adults. Little is known about foetal impairment in mothers infected with SARS-CoV-2. Objective: The goal of the present study is to develop and validate a behavioural evaluative scale of olfactory perception in healthy new-borns and to apply this scale to new-born children of women infected with COVID-19 during pregnancy comparing to new-born children of women without COVID-19 infection history. Methods: This is a retrospective comparative analytical cohort study of 300 new-borns exposed and unexposed to COVID-19 during pregnancy. The data collection will follow the experimental procedure in a previous study that explored odours of the maternal breastmilk, vanilla (sweet) and distilled water (neutral). A coffee smell was implemented as an addition to this previous study in order to include the acid/bitterness category to the categories of stimuli. Discussion: It is feasible to argue the hypothesis of the involvement of the foetus' olfactory bulb during intrauterine life as one of the indelible pathophysiological manifestations to the clinical diagnosis of COVID-19 with neurosensory olfactory deficit in foetuses and new-borns affected by intrauterine infection. This study aims to investigate if new-born children of women infected with COVID-19 during pregnancy have olfactory sensory changes. The clinical trial was registered in the Brazilian Registry of Clinical Trials (ReBEC- RBR-65qxs2).