During early pregnancy, it is common to experience nausea and vomiting. This is often referred to as "morning sickness" but symptoms can occur at any time of the day.
Morning sickness affects 70% to 80% of pregnant women. Symptoms usually begin 4–6 weeks after your last period and peak between 9 and 16 weeks. In 9 out of 10 women, symptoms disappear by 22 weeks gestation (the end of the first trimester). Up to 10% of women continue to have symptoms until their baby is born.
Normal morning sickness won't threaten your baby's health as long as you are able to keep food down, eat a well-balanced diet and drink plenty of fluids. However, if you are pregnant and experience nausea and vomiting that is severe and ongoing, you should see your midwife or doctor.
What are symptoms of morning sickness?
Symptoms can occur at any time of the day and often include:
- dry retching (like vomiting, but nothing is thrown up)
- food smell or sight sensitivity (certain smells or the sight of some foods can trigger nausea).
Not all women experience morning sickness in the same way.
- Some women have only occasional queasy moments while others feel nauseous and sick almost constantly but never vomit.
- Some women vomit now and again, while others vomit more frequently and feel better afterwards.
- In some women, the nausea and vomiting are severe and ongoing. They are unable to keep down fluids or food, causing them to lose weight and become dehydrated. This is called hyperemesis gravidarum and occurs in less than 2% of pregnant women (2 in every 100 pregnant women). Read more about hyperemesis gravidarum.
When to see a doctor for morning sickness
If you are vomiting and can’t keep any food or drink down, there is a chance that you could become dehydrated or malnourished. Contact your GP or midwife immediately if you:
- have very dark-coloured urine or do not pass urine for more than 8 hours
- are unable to keep food or fluids down for 24 hours
- feel severely weak, dizzy or faint when standing up
- have abdominal (tummy) pain
- have a high temperature (fever) of 38°C (100.4°F) or above
- vomit blood
- have pain when passing urine or any blood in your urine (this may be a urine infection).
What causes morning sickness?
The exact cause of morning sickness is unclear, but the symptoms are thought to be due to a combination of factors such as:
- high levels of pregnancy hormones, in particular, human chorionic gonadotrophin (hCG) and oestrogen
- fluctuations in blood pressure, particularly lowered blood pressure
- altered metabolism of carbohydrates
- the enormous physical and chemical changes that pregnancy triggers.
Morning sickness may be more likely to happen:
- when you have an empty stomach
- if you are stressed or anxious
- if you experience strong smells.
What increases my risk of morning sickness?
Morning sickness can occur in any pregnant woman, but some women are more prone to it. If you are pregnant you are more likely to develop morning sickness if:
- it is your first pregnancy
- you experienced nausea and vomiting in a previous pregnancy
- your unborn baby is a girl
- you have a family history of nausea in pregnancy
- you have a history of travel or motion sickness
- you get nausea when using contraceptives
- your BMI is 30 or higher
- you have a multiple pregnancy such as twins or triplets.
Self-care – what can you do to feel better?
Tips to manage morning sickness
- Try eating a bland, protein-rich diet.
- Eating 5 to 6 small meals a day can help.
- Have something to eat before getting out of bed in the morning (toast, cracker).
- Try eating a light snack high in protein and complex carbs (a banana muffin and a glass of milk, cheese and a handful of dried apricots) just before you go to sleep. You are less likely to be hungry in the morning.
- Avoid foods that are fatty or make you feel nauseous.
|Fluids and hydration
- Keep yourself well hydrated.
- If you find it difficult to drink water, try sucking on crushed ice.
- Many women find icy cold fluids easier to get down.
- Small frequent sips of water, between meals, are easier to keep down.
- You can also keep yourself hydrated by drinking soups, smoothies and shakes.
- Ginger taken as ginger tea, ginger-containing foods or ginger capsules (from a pharmacy) may help calm the tummy.
- Studies have shown that eating about 1 gram of ginger per day for at least 4 days can reduce nausea and vomiting in early pregnancy.
|Vitamin B6 (pyridoxine)
- Bananas, potatoes, watermelon, chickpeas are all rich in this nutrient. Talk to your lead maternity carer about taking vitamin B6 supplements.
|Exercise and fresh air
- Keep active – regular, gentle exercise helps.
- Getting fresh air may help you feel better. Take a short walk, turn on a fan, or try to sleep with the window open. When you are cooking, open windows to get rid of smells that may cause nausea.
- Do not smoke cigarettes. Ask other people not to smoke around you.
|Rest and relaxation
- Get enough sleep, take rests if needed and avoid getting overtired.
- Don't try to maintain the same schedule or level of activity as you did before your pregnancy.
- Avoid stress and try stress-reduction techniques, like meditation.
- Wear comfortable clothes without tight waistbands.
|Brushing your teeth
- Delay brushing your teeth in the morning if you find it makes you sick. Instead, wait to brush until your stomach feels more settled.
- Also, wait about half an hour after eating to brush your teeth.
|Acupressure bracelets or acupuncture
- Try sea-sickness acupressure bracelets or acupuncture. Some women find these helpful and there does not appear to be evidence of harm.
Vomiting in pregnancy Ministry of Health, NZ, 2013
Nausea and morning sickness NHS Choices, UK, 2014
Pregnancy – morning sickness Better Health Channel, Australia, 2014
- Effects of ginger for nausea and vomiting in early pregnancy: a meta-analysis. J Am Board Fam Med. 2014 Jan-Feb;27(1):115-22.1.
Information for health professionals on morning sickness
This page will be of most interest to clinicians (nurses, doctors, pharmacists and specialists) or those seeking more detail.
The following information about nausea and vomiting in pregnancy is taken from Auckland Regional HealthPathways, accessed January 2020:
Pregnancy‑related nausea and vomiting occurs in 60–70% of pregnancies. Persistent and severe vomiting (hyperemesis gravidarum) occurs in 1–2%.
In severe hyperemesis, prescribe thiamine to prevent Wernicke encephalopathy.
- Check patient's history.
- Ask about symptoms that may suggest another diagnosis.
- Carry out an examination.
- Arrange MSU as a urinary tract infection may be asymptomatic in pregnancy, check dipstick ketones in urine, glucose finger prick.
- Check whether the patient needs bloods for FBC, electrolytes, creatinine, LFT, and TSH.
- Decide whether the patient has mild, moderate or severe or persistent vomiting.
- Provide information on nausea and vomiting in pregnancy.
- Continue or start folic acid and iodine.
- Consider non-pharmacological options as below and start pregnancy-specific multivitamins.
- Consider starting pyridoxine (vitamin B6) 25 to 50 mg orally three times daily. This is fully funded and has been shown to improve nausea in pregnancy.
- Heartburn/GORD has been associated with increased severity of nausea and vomiting in pregnancy. Managing GORD by making dietary changes or using medications for GORD may improve symptoms.
- Small amounts of fluid frequently
- Small frequent meals, high in carbohydrate, low in fat
- Avoid smells or foods that trigger symptoms
- Ginger – taken as ginger tea, ginger-containing foods, ginger capsules
- Wrist acupressure and acupuncture (Some women find this helpful. There is no evidence of harm, however, evidence is limited).
- Metoclopramide – compatible with pregnancy: 10 mg three times daily orally, IM, or IV (not for regular use > 5 days)
- Cyclizine – compatible with pregnancy: 50 mg three times daily orally, IM, or IV
- Prochlorperazine (Stemetil) – compatible with pregnancy: dose is dependent on route comes in buccal, suppository, IM, and oral
- Promethazine (Phenergan) – compatible with pregnancy: 10 mg to 25 mg orally or 12.5 to 25 mg IM good at night due to sedative effect
Use any antiemetic at the lowest dose for the shortest time it is required.
Manage for mild, plus:
· urinalysis for ketones.
· FBC, electrolytes, creatinine, LFT, and TSH.
- Arrange intravenous (IV) fluids.
· If the patient has improved and can tolerate small oral intake, discharge home with a prescription for oral antiemetics. Advise that taking these regularly or early in symptoms of nausea may prevent the need for further IV or intramuscular (IM) treatment.
· If there is no improvement after IV fluids and antiemetics, request an acute gynaecology assessment.
· Review by LMC or general practitioner in 2 to 3 days, or sooner if required.
· Consider medications as per section 5 above for gastro-oesophageal reflux (GORD) in all patients requiring IV fluid replacement.
- For patients requiring IV rehydration on more than one occasion, do an ultrasound as described in the severe or persistent section.
- If criteria are met, consider referral to Dietitian Services.
Severe or persistent
Consider referral to the Gynaecology Assessment Unit via the on-call registrar.
Manage as for mild-moderate, plus:
- Arrange an ultrasound scan if not already done, checking for multiple or molar pregnancy.
· FBC, electrolytes, creatinine, LFT, and TSH.
· TFTs - abnormal in two-thirds of patients. Asymptomatic patients with a suppressed TSH level and normal FT4 and FT3 have subclinical hyperthyroidism.
- Prescribe thiamine 50 mg orally once daily, antiemetics and consider medications for gastro-oesophageal reflux (GORD) as outlined above.
- Consider ondansetron (probably compatible with pregnancy) if other antiemetics are not working.
- Refer all women with severe or persistent hyperemesis to Dietitian Services. If also requesting a gynaecology assessment, they may arrange this referral.
- Social worker input is available by referral from the Gynaecology Assessment Unit or LMC, provided the patient is booked to deliver via the ADHB, Waitemata and Counties DHB maternity system.
Nausea and vomiting in pregnancy BPAC, NZ, 2011
Treatment of nausea and vomiting during pregnancy Christchurch Medicines Information Service, NZ, 2016
Hyperemesis gravidarum – assessment and management Australian Family Physician, 2017
Management of nausea and vomiting in pregnancy BMJ 2011 Jun 17;342:d3606
Regional HealthPathways NZ
Access to the following regional pathways is localised for each region and access is limited to health providers. If you do not know the login details, contact your DHB or PHO for more information: