Nausea and vomiting in pregnancy: causes, relief and warning signs

Why do I feel sick in early pregnancy?

Nausea is linked to the rapid rise in pregnancy hormones, especially hCG, which is produced by the developing placenta. It is more common and often stronger with twins, if you had nausea in a previous pregnancy, or if you get travel sickness. Despite the name "morning sickness", it can happen at any time of day.

When it stays moderate, it has no consequences for your baby, even if you eat little for a few weeks: your own reserves are enough. It is one of the first things patients discuss with their doctor during the antenatal care described on our Giving birth in Paris page.

How long does morning sickness last?

Stages are given in weeks of amenorrhoea, counted from the first day of your last period. Vomiting that appears for the first time after the first trimester is not typical of pregnancy sickness: another cause should be looked for.

How can I ease nausea day to day?

• Eat little and often: 5 to 6 small snacks or meals a day, without waiting until you are hungry.
• In the morning, nibble something dry (toast, crackers, bread) before getting up.
• Drink in small sips throughout the day, preferably between meals.
• Avoid fatty, fried or very spicy foods and smells that trigger nausea; cold foods smell less.
• Follow your cravings: it is better to eat what you can keep down than to force yourself.
• Rest: tiredness makes nausea worse.
• Ginger may help some women, according to trials of variable quality (Cochrane review, Matthews et al., 2015).

The CNGOF recommends stopping pregnancy multivitamins and iron during this period, but continuing folic acid.

Other small steps can help: airing rooms, avoiding cooking strong-smelling dishes yourself, brushing your teeth away from mealtimes if toothpaste makes you gag, and wearing loose clothing. Wrist acupressure bands are safe, but there is no clear evidence that they work. Once the nausea has passed, gradually return to a varied diet, following our advice on diet during pregnancy.

What medicine can I take for morning sickness?

When nausea affects your daily life, treatment can be prescribed. The UK guidelines of the Royal College of Obstetricians and Gynaecologists (RCOG, 2024) and the French CNGOF expert consensus (2022) state that several medicines can be used; the CNGOF stresses that no class is better than another and that the medicines with the fewest side effects should be chosen:

• First line: the combination doxylamine-pyridoxine (vitamin B6), certain antihistamines and other anti-sickness medicines such as metopimazine.
• Second line: metoclopramide, as a short course because of possible neurological side effects; ondansetron, which has proven effectiveness, with a very small increase in the absolute risk of cleft lip and palate when used in the first trimester, to be weighed against the risks of uncontrolled hyperemesis.
• Combinations are possible if one medicine is not enough.

Do not take any medicine, even over-the-counter or herbal, without medical advice: the choice, dose and duration depend on your situation. See our article on medicines during pregnancy.

What is hyperemesis gravidarum?

Hyperemesis gravidarum is the severe form of pregnancy sickness. It affects a small minority of women. According to the CNGOF, it is distinguished from ordinary pregnancy sickness by weight loss of at least 5% of your pre-pregnancy weight, signs of dehydration or a PUQE score (a short severity questionnaire) of 7 or more.

Treatment is often given in hospital, sometimes as a day patient:

• an intravenous drip of saline with added potassium, with blood salt (electrolyte) checks;
• anti-sickness medicines by injection;
• vitamin B1 (thiamine) to prevent a rare but serious neurological complication, Wernicke's encephalopathy;
• blood-thinning injections to prevent clots during the hospital stay, depending on your situation;
• psychological support: hyperemesis is exhausting and can lead to anxiety or depression.

You can go home once you can drink and take your medicines by mouth again. Treatment then continues and is reduced gradually, without stopping suddenly. Ending the pregnancy should only be considered once every treatment option has been tried. It tends to recur in a later pregnancy, so early treatment can be planned ahead.

What else can cause vomiting in pregnancy?

Your doctor looks for another cause when the vomiting is unusual:

• Pregnancy-related causes: twin pregnancy, molar pregnancy (a rare abnormality of the placenta seen on ultrasound).
• Digestive causes: gastroenteritis, reflux, appendicitis, gallstones, pancreatitis, bowel obstruction.
• Urinary causes: kidney infection (pyelonephritis).
• Hormonal or metabolic causes: overactive thyroid, poorly controlled diabetes.

A clinical examination (weight, blood pressure, pulse, feeling the abdomen), an ultrasound scan and a blood test are usually enough to clarify things. Testing urine for ketones is not a good indicator of dehydration and should not be used to judge severity (RCOG, 2024). A temporary overactive thyroid on blood tests is common with hyperemesis and usually corrects itself.

When should I go to the maternity unit urgently for vomiting?

See your doctor or go to your maternity unit's emergency department promptly, and call 15 or 112 in France, or your local emergency number, if you feel faint, or if:

• you have not kept down any fluid or food for 24 hours;
• you pass little, dark urine, have a dry mouth or feel dizzy when standing up;
• you have lost weight quickly;
• you vomit blood or brown fluid;
• you have a fever, severe abdominal pain or a burning feeling when passing urine;
• you have vaginal bleeding;
• you feel confused or very weak, or have problems with your vision or balance;
• you feel so low that you are thinking of ending the pregnancy: talk about it, there are solutions.

In France, sick leave can be prescribed if nausea stops you working. For severe nausea, an appointment at the practice or a video consultation (via Doctolib) can be offered; book on Doctolib or call +33 1 43 79 59 79.

Frequently asked questions

General information article: it does not replace a medical consultation. In an emergency, call 15 or 112 in France, or your local emergency number.