# What Causes Changes in Taste and Smell During Pregnancy Changes in taste and smell are among the
Last week, morning coffee was still an indispensable daily ritual. Today, even a whiff of its aroma causes nausea and an immediate retreat from the kitchen. If this sounds familiar, you're not alone – and you're definitely not imagining it. Changes in taste and smell during pregnancy are among the most common yet least discussed side effects of pregnancy, even though the vast majority of expectant mothers experience them.
Science sees a clear cause behind this: the dramatic hormonal transformations that occur practically from the first day after fertilisation fundamentally affect the way the brain processes sensory input. This is not a matter of whims or hypersensitivity – it is a physiological process with a deep evolutionary purpose. And that is precisely why it is worth understanding.
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What is actually happening in the body and why are the senses suddenly so different
Immediately after conception, the body begins to flood with human chorionic gonadotropin, or hCG for short – the hormone also responsible for a positive pregnancy test result. Its levels rise rapidly during the first trimester, peaking at around the eighth to tenth week. This substance is considered one of the main culprits behind heightened sensitivity to smells and changes in taste perception. Acting alongside it is oestrogen, whose concentration in the body also rises sharply and which has a demonstrable effect on the olfactory receptors in the nose.
The result is a condition that experts refer to as hyperosmia – a significantly increased sensitivity to smells. Women in the first trimester describe being able to smell food cooking two floors up, identify a person's perfume from across the room, or detect an odour that their partner cannot perceive at all. This is not imagination. Research shows that olfactory sensitivity is genuinely measured differently during pregnancy – the brain receives and processes smell signals more intensely than before pregnancy. A study published in the journal Chemical Senses confirms that pregnant women display a lower threshold for olfactory detection, particularly in the first trimester.
And coffee? It has become the very symbol of this phenomenon. The caffeine and volatile compounds released during coffee preparation are, for an oversensitised olfactory system, nothing short of an assault. The brain during this period is programmed to avoid intense, bitter, or fermented aromas – and coffee ticks several of these boxes at once. It is therefore no surprise that coffee becomes the number one enemy for many pregnant women, even though it was their favourite drink just recently.
But the changes are not limited to smell alone. Taste changes just as significantly, albeit through a slightly different mechanism. Many pregnant women describe a metallic taste in their mouth, which tends to appear at the very start of pregnancy. This phenomenon even has its own medical term – dysgeusia. It arises as a result of hormonal changes that affect the composition of saliva and the way taste buds on the tongue respond to stimuli. Sweet foods suddenly taste different, sour things may conversely become surprisingly appealing, and foods a woman has loved her entire life can suddenly provoke disgust.
Consider Markéta, a thirty-year-old teacher from Brno, who shared her story on a parenting forum: throughout her entire pregnancy, she could not even come near meat, even though before becoming pregnant, a steak had been her favourite Sunday dinner. Instead, she found herself irresistibly drawn to lemon sorbet and pickled gherkins – a combination she would never have considered before. Stories like these are completely normal in pregnancy, and science offers a clear explanation for them.
The evolutionary logic behind aversion to coffee and other smells
You may be wondering: why does the body actually do this? Why did evolution choose this particular way of complicating the daily lives of pregnant women?
The answer is surprisingly elegant. One of the most widely accepted theories holds that heightened olfactory sensitivity and aversion to certain foods serve as a protective mechanism for the developing foetus. During the first trimester, when the embryo's organs are at their most vulnerable and cell division is occurring most intensely, it is critically important that the mother does not consume potentially harmful substances. And the foods that most commonly trigger aversion – meat, alcohol, coffee, strongly aromatic foods – are also precisely those that may contain toxins, caffeine, or other substances undesirable for foetal development.
As evolutionary biologist Gordon Gallup aptly put it: "Morning sickness and food aversions are not an illness – they are sophisticated adaptations that protect the mother and child during the most critical period of development."
Caffeine is a particularly interesting case in this regard. The World Health Organization recommends limiting caffeine intake during pregnancy to a maximum of 300 mg per day, while many experts recommend an even lower intake – around 200 mg. A pregnant woman's body metabolises caffeine significantly more slowly than outside of pregnancy, meaning its effects last longer and are more intense. An aversion to coffee may therefore be a literal biological warning, programmed deep into the instincts.
What is also interesting is that olfactory memory is closely linked to emotions and the limbic system of the brain. Smells that before pregnancy evoked pleasant associations – morning coffee as a symbol of comfort and ritual – can suddenly be reprogrammed during pregnancy into negative signals. The brain simply rewrites the previous experience and assigns an entirely opposite emotional value to the same smell. It is a fascinating demonstration of just how plastic and adaptable the human brain truly is.
Changes in smell and taste are not evenly distributed throughout the pregnancy. They tend to be most intense in the first trimester, when hCG levels are at their highest. Around the fourteenth to sixteenth week, the situation begins to stabilise for most women, and many find with relief that they are once again able to enter a café without their stomach turning. The second trimester is generally calmer in terms of sensory sensitivity, although certain preferences and aversions may persist right up until birth.
How to cope with it in everyday life
Knowing why these changes occur is reassuring, but living day to day with a hypersensitive sense of smell and fluctuating taste can be genuinely challenging. This is especially true when a woman has not yet told anyone about her pregnancy and has to explain why she is suddenly declining a coffee with colleagues or fleeing a room where someone is reheating their lunch.
Several things can make the situation easier. Ventilating rooms and spending time in fresh air helps significantly in moments when smells in an enclosed space become unbearable. Cold foods tend to have a less intense aroma than hot ones, which is why many pregnant women in the first trimester prefer salads or yoghurt over hot meals. Ginger – whether in the form of tea, candied slices, or capsules – has scientifically supported effects in reducing nausea associated with olfactory triggers, as confirmed by, for example, a review study published in Obstetrics & Gynecology.
When it comes to coffee itself, there are alternatives that can provide a similar sense of ritual comfort without the problematic aroma. Chicory coffee, herbal teas, or warm water with lemon can replace the morning ritual in a way that the body tolerates better during this period. Ferwer offers, for example, a range of herbal teas and natural coffee substitutes that are gentle on the sensitive pregnant stomach while still providing the sense of comfort that comes with a warm drink in hand.
It is also important not to underestimate the psychological dimension of the whole situation. Losing beloved tastes and smells – and the rituals and pleasures associated with them – can be emotionally more demanding than it might seem. A morning coffee is not just caffeine; for many women, it is a moment of calm, focus, and pleasure. When this ritual suddenly disappears or turns into an unpleasant experience, it can contribute to the overall fatigue and frustration of the first trimester. Open communication with a partner, family, or midwife about these seemingly "minor" difficulties is therefore just as important as caring for physical health.
The good news is that the vast majority of olfactory and taste changes are temporary. The body gradually returns to its original preferences after birth – and in many cases already during the second trimester. Some women even describe enjoying coffee more after giving birth than they did before, as if looking forward to a reunion with an old friend. Others find that their taste preferences have permanently shifted and that some foods they loved before pregnancy no longer appeal to them as much.
Pregnancy is a transformative experience in every sense – and that applies even to something as seemingly mundane as a morning cup of coffee. Understanding what is happening in the body and why can transform the frustration of inexplicable bodily reactions into a respect for its wisdom. The body simply knows what it is doing – even when it appears, in the moment, to be acting entirely on a whim.
