The journal Chemical Senses isn’t usually at the top of my reading list, but it certainly came in handy to answer this question. In 2004 it published an article entitled “A Longitudinal Descriptive Study of Self-Reported Abnormal Smell and Taste Perception in Pregnant Women.” The article described the “odor hedonics” of pregnancy. Say what? I love it when they use fancy terms instead of just saying the perception of pleasant or unpleasant smells in pregnancy.

This article and others confirm the idea that pregnant women have an especially acute sense of smell. This is more common in early pregnancy and disappears after delivery. These authors go on to speculate that the abnormalities in smell may be explained by some natural internal mechanism to avoid poisons. They noted that the odors of cigarette smoke, alcohol, and coffee in particular were commonly reported as being perceived as stronger than normal during early pregnancy.

It is postulated that this bionic sense of smell is caused by an increase in hormones, specifically plasma estradiol (an estrogen). Women also have an increase in estradiol during the menstrual cycle, with a peak at ovulation (around day 14). Some women report increased sense of smell during this period of their cycle as well.

Whatever the reason or cause, I have found the bionic sense of smell very troublesome. During my own wife’s pregnancy, I was forced to shower immediately upon entering the house, loofah myself aggressively with a rough sea sponge, brush my teeth excessively, and scrape my tongue with barbaric oral-hygiene implements… And despite my best efforts, I was still occasionally put outside like a bag of rotten garbage.