The Pregnancy Super-Smell, Explained
There's a moment — usually somewhere in the first few weeks of pregnancy — where the world starts to smell… different. Not in a nice way. The coffee your partner used to make you every morning becomes unbearable. The fridge smells like a crime scene. Someone two rows in front of you on the bus puts on hand cream and suddenly you're gagging into your sleeve.
If that sounds familiar, you're not imagining it, and you're not being dramatic. You're experiencing hyperosmia — and it's one of the most common, and most under-talked-about, parts of early pregnancy.
Hyperosmia is a heightened sensitivity to smell. Everyday scents feel stronger, sharper, and more intrusive — and smells you'd never normally notice become impossible to ignore. It's not a disease or a disorder in its own right; it's a symptom. It shows up in a few different contexts (migraines, certain neurological conditions, hormonal shifts), but by far the most common cause is pregnancy.
Studies estimate that up to two-thirds of pregnant women report some degree of altered smell perception, with hyperosmia being the most frequent change. It tends to peak in the first trimester and ease off in the second — though for some women, it lingers the whole way through.
The honest answer is: scientists don't fully agree yet. But there are a few strong, well-evidenced theories, and they overlap in interesting ways.
In early pregnancy, levels of human chorionic gonadotropin (hCG) and oestrogen rise dramatically. Both hormones are closely linked to the way the brain processes smell. Oestrogen in particular is known to influence the olfactory bulb — the part of the brain responsible for interpreting scent — which is why smell sensitivity also shifts during the menstrual cycle, puberty, and menopause.
Pregnancy just cranks that dial to its highest setting.
There's a compelling evolutionary explanation too. The first trimester is when a baby is most vulnerable to toxins, bacteria, and spoiled food. A sharper sense of smell — combined with nausea as a deterrent — may have evolved to stop pregnant women eating or inhaling anything that could harm a developing baby. It's why the smells that tend to trigger the strongest reactions are often meat, alcohol, cigarette smoke, strong cheeses, and chemical cleaners — things that historically carried real risk.
Your nose, essentially, is doing overtime to keep your baby safe. Which is lovely in theory, and absolutely infuriating in practice when you can't stand the smell of your own shampoo.
Hyperosmia and morning sickness are deeply linked. Research consistently shows that women who experience stronger smell sensitivity also tend to experience more nausea and vomiting in pregnancy (NVP). The relationship goes both ways — strong smells can trigger nausea, and being nauseous can make you more reactive to smells. It's a loop, and it's exhausting.
Every woman experiences it differently, but the common threads are:
The psychological toll is real. Many women describe feeling trapped in their own homes, dreading social situations, or quietly panicking about the walk to work. It isn't a minor inconvenience — it's a genuine shift in how you move through the world.
For most women, hyperosmia begins to ease around weeks 12–14, as hCG levels plateau and begin to fall — for me, it only ended when I gave birth. But by the second trimester, smell sensitivity usually softens significantly. Some women find it returns briefly in the third trimester, and a small number report lasting changes to their sense of smell even postpartum — though these usually resolve with time.
If your smell sensitivity is severe enough to stop you eating, drinking, or leaving the house, please do speak to your midwife or GP. It can be a sign of hyperemesis gravidarum (HG), a more serious form of pregnancy sickness that needs proper support.
There's no cure for hyperosmia — you can't switch it off — but you can work with it rather than against it. Things that genuinely help:
That first point is the one we built Bump & Breathe around. When a smell ambushes you — in a café, on a train, in your own kitchen — having something familiar, grounding, and pregnancy-safe to breathe in can be the difference between a bad five minutes and a ruined afternoon. Our balms were made for exactly those moments: a small tin, four clean ingredients, and a scent you chose instead of one you've been handed.
If there's one thing worth taking away from all of this, it's that hyperosmia is real, it's physiological, and it's not something you need to push through silently. Your nose is doing something extraordinary — it's just doing it a bit loudly.
Be gentle with yourself. Open the window. Find your scent.
And know that for most women, the worst of it really does pass.