Morning sickness and hyperemesis gravidarum

Nausea and vomiting in pregnancy (NVP)

Despite often being called morning sickness, nausea and vomiting in pregnancy (NVP) can happen at any time of the day and is thought to be caused by hormonal changes in early pregnancy (NHS, 2024; RCOG, no date).

The unpleasant feelings usually start between weeks 4 and 7 of pregnancy. For 9 in 10 people they settle by 20 weeks, although they can last longer (NHS, 2024; RCOG, no date).

Mild to moderate pregnancy nausea can feel difficult, but it is usually possible to continue with normal activities and there is no evidence it will harm the baby (NHS, 2024; RCOG, no date; Pregnancy Sickness Support, no date a).

It can be helped by (Bumps, 2025; NHS, 2024; RCOG, no date):

• Getting plenty of rest
• Keeping up a normal intake of fluids such as water (8 cups or glasses a day) - taking small sips throughout the day can help
• Eating whatever appeals rather than worrying too much about eating the ‘right’ thing
• Eating smaller amounts of food regularly rather than big meals
• Choosing food that is high in carbohydrate but low in fat, such as potato, bread, rice or pasta
• Eating a plain piece of toast or cracker in the morning
• Avoiding strong-smelling food, or food that makes nausea worse
• Choosing cold food rather than hot food if the smell of hot food makes nausea worse
• Eating food or drinks with ginger, although this doesn’t work for everyone. Talk to a pharmacist about any supplements.
• Trying acupressure, by wearing a wrist band or pressing the wrist with fingers

Who is more likely to get pregnancy nausea?

Some people may be more likely to get pregnancy nausea. This includes people who (NHS, 2024):

• Are pregnant for the first time
• Have had vomiting or sickness in a previous pregnancy
• Are pregnant with twins or multiples
• Tend to get motion sickness (for example, car sickness)
• Have a history of migraine headaches
• Have a BMI of 30 or more
• Have experienced feelings of sickness previously when taking contraceptives containing oestrogen

Hyperemesis gravidarum (HG)

For 3 in 100 women and birthing people, the pregnancy nausea and vomiting is severe and has a huge impact on day-to-day life. When pregnancy nausea is this serious, it is called Hyperemesis Gravidarum [hi-per-EM-i-sis grav-id-AR-um] or HG, and often requires medical treatment (RCOG, no date).

For most pregnant woman and birthing people, the symptoms of HG peak at 9-13 weeks and may improve around 16-24 weeks, but for 1 in 5 they last the entire pregnancy. The pregnant woman or person finds no relief with diet or lifestyle changes and may be unable to eat food or fluids without vomiting (RCOG, no date; Pregnancy Sickness Support, no date a).

This can lead to (RCOG, no date; Pregnancy Sickness Support, no date a):

• Dehydration 
• Weight loss
• Emotional and physical distress

It’s important not to delay seeking support, as HG needs medical treatment or it can lead to complications. Contact the midwife or GP or get advice from NHS 111 if the vomiting is so extreme that the pregnant woman or person cannot eat normally (RCOG, no date; Pregnancy Sickness Support, no date a).

What is the treatment for NVP or HG?

If self-help isn’t working, many women and birthing people can be treated at home or as outpatients in hospital (RCOG, no date). At first, a doctor will normally prescribe an antihistamine, which can help with sickness (antiemetic) (Bumps, 2025; NHS, 2024).

If this isn’t enough, the pregnant woman or person may be offered anti-nausea medicine by mouth, injection or suppository (a tablet inserted into the bottom). These medicines are generally considered safe for the baby (RCOG, no date).

There are different medicines that can be tried if others aren’t effective. Sometimes two or more medicines might be given at the same time (RCOG, no date).

In some circumstances, including severe dehydration, the pregnant woman or person may need to be admitted to hospital. They will be rehydrated with a drip and given anti-nausea medicine. They will also be offered a B vitamin called thiamine (RCOG, no date).

If anti-nausea medicine doesn’t stop the vomiting, corticosteroids might be offered. These are highly effective at treating nausea and vomiting. Usually, they can be stopped by week 20 of pregnancy. A test for gestational diabetes will be offered if taking corticosteroids (RCOG, no date).

Some women or pregnant people are discharged from hospital before the birth with medication to take at home. Sometimes they may be assessed again and readmitted (RCOG, no date).

Will medications affect the pregnant woman or person, or the baby?

A doctor will be able to discuss the risks and benefits of taking medicines during pregnancy (RCOG, no date).

Bumps (Best Use of Medicines in Pregnancy) has a short animation (available in several languages), about using medicines to treat nausea and vomiting in pregnancy.

When it lasts for a long time, severe nausea and vomiting may cause the baby to have a low birthweight. This is why scans may be offered to monitor their growth (RCOG, no date).

There may be other complications for the baby, as well as the mother or birthing parent, if severe sickness isn’t treated (RCOG, no date).

Emotional impact

Living with HG can be very distressing. It may affect the pregnant woman or person’s social life, ability to work, look after other children or do normal daily activities. They may become depressed or anxious (Pregnancy Sickness Support, no date a; RCOG, no date).

Speak to a healthcare professional if pregnancy nausea and vomiting is causing low mood or worry (RCOG, no date).

The charity Pregnancy Sickness Support provides information, support and resources for those experiencing hyperemesis gravidarum. 

We also have articles on supporting mental health during pregnancy and the perinatal period.

After the baby is born

Symptoms of HG usually resolve after the baby is born. The midwife or GP can continue to provide support if needed (RCOG, no date).

The chance of experiencing HG again in the next pregnancy is very high. Recovering from any trauma in the first pregnancy and planning for the next can help. Pregnancy Sickness Support provides useful tips and offers counselling.