Notes & Queries, 19th December 2013: What makes a smell good or bad?
image generated by Grok Research from Estonia would suggest a degree of olfactory conditioning occurs during the second trimester of pregnancy. The study, published in 2006 by Frankel & Rummo, documents a three year investigation into the development of the olfactory sense. Among their findings, the writers demonstrated that, around the 20th week of pregnancy, the womb begins to secrete fluids that emit unpleasant odours and induce mild nausea in a developing foetus. Laboratory analysis of these odours revealed that they are similar in nature to those indicating the presence of disease, stagnation or decomposition. It is likely therefore that this process evolved as a survival trait. Although there is no definitive proof, the authors speculate that these fluids also play a role in the fine-tuning and 'reinforcement' of the nervous system. They observed that olfactory refinement continues into the third trimester. Children who are born prematurely may have a diminished or...