Pregnancy and olfaction: a review.

E Leslie Cameron

doi:10.3389/fpsyg.2014.00067

Abstract

Many women report a heightened sense of smell during pregnancy. Accounts of these anecdotes have existed for over 100 years, but scientific evidence has been sparse and inconclusive. In this review, I examine the literature on olfactory perception during pregnancy including measures of self-report, olfactory thresholds, odor identification, intensity and hedonic ratings, and disgust. Support for a general decrease in olfactory thresholds (increase in sensitivity) is generally lacking. There is limited evidence that some suprathreshold measures of olfactory perception, such as hedonic ratings of odors, are affected by pregnancy, but these effects are idiosyncratic. In this review, I explore the hypotheses that have been put forth to explain changes in olfactory perception during pregnancy and provide suggestions for further research.

Highlights

Anecdotal reports of heightened sense of smell during pregnancy are common, and the majority of pregnant women report increased olfactory sensitivity (Nordin et al, 2004; Cameron, 2007, 2014)
Pregnant women have been tested on both low-level threshold tasks and high-level suprathreshold olfactory tasks, but further research is needed using both types of task
Odor detection across a range of concentrations using the method of constant stimuli would enable an examination of differences between psychometric functions of pregnant and non-pregnant women. Suprathreshold measurements, such as cross-modal matching, could reveal differences that have not been demonstrated with more common methods of measuring olfactory perception

Summary

Introduction

Anecdotal reports of heightened sense of smell during pregnancy are common, and the majority of pregnant women report increased olfactory sensitivity (Nordin et al, 2004; Cameron, 2007, 2014). Pregnant women have been tested on both low-level threshold (detection) tasks and high-level suprathreshold (identification) olfactory tasks, but further research is needed using both types of task. It is important to distinguish between sensory and cognitive changes in the olfactory system that may be brought about by pregnancy.

Results

Conclusion