What the metallic taste is

The NHS keeps a page on metallic taste as a symptom in its own right, and lists "being pregnant" among the common causes. Its verdict for the pregnancy version is short: "The taste is usually temporary and clears up by itself."

That is genuinely all the national guidance says about it. There is no NICE recommendation, no treatment pathway and no investigation, because it is not a problem — it is a side effect of the same hormonal changes that alter smell and appetite in the first trimester. The NHS does add one mechanism worth knowing: "Sometimes, a lost or changed sense of smell can cause a metallic taste in your mouth." Taste and smell are so intertwined that a change in one is often experienced as a change in the other.

Why aversions arrive at the same time

Metallic taste, nausea and food aversions travel together because they share a timeline. NICE's clinical summary for nausea and vomiting in pregnancy sets it out: it "usually begins between 4–7th weeks, peaks between 9–16th weeks, and resolves by 16–20 weeks of pregnancy". RCOG puts the resolution figure in plainer terms: nausea and vomiting "settles by 20 weeks in 9 out of 10 pregnant women".

The NHS's own page on vomiting and morning sickness gives the same shape: it is very common in early pregnancy and usually improves as pregnancy goes on. That is the window most people's aversions live in. Coffee, tea, meat, onions, garlic and anything cooking are the ones people report most, and they typically go off in the same weeks the nausea is worst and quietly return afterwards.

NICE adds a diagnostically useful line: "Onset of symptoms after 11 weeks of gestation usually suggests an alternative cause of symptoms unrelated to pregnancy." A metallic taste and nausea that begin for the first time in the second half of pregnancy are worth mentioning rather than filing under pregnancy.

What it is not

It is not a way of predicting your baby's sex. No national body lists taste changes as a sign of anything except pregnancy itself. The volume of search traffic on that question does not create evidence for it.

It is also not a sign that something is wrong with your diet. Aversions are not the body signalling a deficiency; that is a folk theory rather than a finding in guidance.

Other causes worth ruling out

Being pregnant does not stop the ordinary causes applying. The NHS's list of common causes of a metallic taste includes:

Gum disease. The NHS lists a bad taste in the mouth as one of the things gum disease leads to, and gums bleed and swell more readily in pregnancy. Worth a dental check — NHS check-ups and treatment are free while you are pregnant and for a year after you give birth.
Certain medicines, naming metronidazole and zopiclone. The NHS's advice is to speak to a pharmacist and not to stop prescribed medicine without medical advice.
Colds, sinus infections and other airway problems. The taste "should go away once the problem has cleared up".
Indigestion, which is extremely common in pregnancy. The taste "should go away after treating indigestion".
Cancer treatments such as chemotherapy and radiotherapy.

What actually helps

Nothing has been tested for the taste itself, so this is practical rather than evidence-based:

Sharp and sour flavours — citrus, pickles, vinegar — tend to cut through it better than sweet ones.
Salt in cooking, for the same reason.
Brushing and tongue cleaning, plus keeping up with dental appointments.
Sugar-free gum or mints between meals.
Eating cold food, which smells less. Aversions are often driven by smell rather than taste.
Letting other people cook, or eating things that require none.

For the nausea that usually comes with it, NICE's antenatal guideline recommends ginger as a non-pharmacological option for mild-to-moderate symptoms, and offering an antiemetic to those who want a medicine. Its wording is that these should be discussed with you, taking into account your preferences and your experience in previous pregnancies.

The point at which aversions need reporting

An aversion is a nuisance. Not being able to eat or drink normally is a clinical problem. NICE defines hyperemesis gravidarum as nausea and vomiting "severe enough to cause an inability to eat and drink normally", strongly limiting daily activities.

RCOG gives the scale: hyperemesis "can affect up to 3 in 100 pregnant women", and "1 in 5 affected women may need admission to hospital for treatment". Several anti-sickness medicines are available, and RCOG states that while some are not licensed for use in pregnancy, "they are considered safe for you and your baby".

The practical threshold: if you cannot keep fluids down for a day, are losing weight, or are producing very little urine, that is a call, not a wait.

When to call someone

Your GP if the metallic taste does not go away, or has no obvious cause (NHS).
A dentist if your gums bleed when you brush or eat, or are painful and swollen. Care is free in pregnancy and for a year afterwards; ask your midwife or GP about the maternity exemption certificate.
Your GP or midwife if nausea or aversions are stopping you eating or drinking, if you are losing weight, or if you have been sick many times in a day.
Your maternity unit or GP the same day if you cannot keep any fluid down, feel very unwell, or are passing very little urine.
Your midwife if a metallic taste or new nausea begins for the first time after 11 weeks, which NICE says usually points to a cause other than pregnancy.

The short version

A mouthful of coins and a sudden hatred of coffee are ordinary first-trimester events that clear on their own, usually by around 16 to 20 weeks. Nothing needs treating. What does need attention is a taste that persists with no cause, gums that are bleeding, or aversions that have crossed the line into not eating and drinking.

Metallic Taste and Food Aversions in Pregnancy