A heightened sense of smell, also known as hyperosmia, is extremely common in pregnancy, affecting up to two-thirds of women in some measure. It can emerge as a symptom from the time your baby is conceived and can make it feel like you are smelling every scent in a room, not just the dominant odour. Cases in pregnancy may be caused by hormonal changes. There’s also a theory that it’s your body’s way of protecting the pregnancy, as smells of toxins like cigarette smoke may become repulsive to you. It will typically subside after childbirth. Outside of pregnancy, hyperosmia is relatively rare and linked to migraines and oral, neurological, and immunological conditions. Ms. Joy Milne, the Scottish midwife who discovered that Parkinson’s disease has a particular smell and helped to develop the first diagnostic test for the disease, famously has hyperosmia. Ms. Milne has heriditary hyperosmia. Fun fact: according to a 2023 interview she did for the BBC Sounds Different with Nicky Campbell podcast, her favourite scent is newborn baby!

The way hyperosmia is treated depends on your symptoms. For example, a case of hyperosmia that causes migraines would be treated with painkillers. Chewing a mint gum is recommended for help with tolerating bad smells in the short term.

Why can I smell everything now I’m pregnant?

Some doctors compare pregnant women’s noses to those of bloodhounds. Being able to smell everything while you’re expecting can be very unpleasant, contributing to headaches, nausea and vomiting. Female hormones impact our sense of smell throughout the menstrual cycle and are also thought to be responsible for altered olfaction in pregnancy, though we don’t really know for certain why this happens. Some theorise that this is nature’s way of protecting the embryo—making mum hyper-aware of things in her environment that may harm her or her baby. Pregnancy also impacts how the thyroid works because of its hormonal changes and metabolic demands on the body, and this can sometimes change your sense of smell and taste. All of this is considered normal, though women with thyroid problems need to have their levels checked with a blood test every four-to-six weeks in pregnancy, with a follow-up test after birth. As with any underlying condition, it’s important that you tell everyone taking care of you in pregnancy if you have a thyroid problem to ensure that you and your baby receive appropriate care. Hyperosmia in pregnancy is usually reported as a first-trimester symptom, and your sense of smell may actually decrease as the weeks progress.

What can I do to cope with my heightened sense of smell in pregnancy?

The way you cope with hyperosmia in pregnancy will depend on your symptoms. If smells tend to trigger your morning sickness, you can take an anti-emetic like Xonvea rather than grinning and bearing it. Headaches can usually be treated with regular paracetamol, though you should always check with your doctor before taking anything while pregnant. You don’t need to suffer any symptoms that disrupt your everyday life; please seek support if this is the case.

Some doctors recommend carrying something that smells of mint with you and sniffing it to keep you comfortable throughout the day. Eating mints is suggested if you feel able to stomach them. You should also ensure the spaces you live in are well ventilated and as fragrance-free as possible. Asking people not to send you flowers to congratulate you on your pregnancy can be a good move, as you do not know which variety will promote a bad reaction. Maintaining good oral hygiene is extremely important in pregnancy, and, as hyperosmia has been linked to gingivitis, it’s especially important to check in with your dentist and stick to a thorough brushing and flossing routine.

Will hyperosmia go away after childbirth?

Your heightened sense of smell may go away before childbirth, as hyperosmia is most strongly associated with the first trimester. If hyperosmia does not subside after birth and is interfering with your day-to-day life, it’s important to report it to your doctor, who may refer you to a neurologist or other specialist, depending on your symptoms. If it is not disruptive, you may consider it a rare gift that could help countless people, as in Ms. Joy Milne’s amazing case.

For more advice on taking care of yourself in pregnancy, labour, and birth, check out Unii’s Antenatal Classes, with prenatal video episodes taught by senior NHS midwives, an award-winning obstetrician and gynaecologist, and six other leading healthcare experts. Only at unii.com.

For more information on symptoms in the first trimester and sustaining a healthy pregnancy, check out Unii's Pregnancy Journey video course with Dr. Shree Datta.

What is hyperosmia in pregnancy?

Unii looks at why some women's sense of smell increases in early pregnancy.