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Hyperemesis Gravidarum: Complete Guide to Severe Pregnancy Sickness

Hyperemesis gravidarum (HG) is not just "bad morning sickness." It's a severe, debilitating condition that affects 1-3% of pregnancies and can leave you unable to eat, drink, or function. If you're struggling with HG - or wondering if your sickness has crossed the line into HG - this guide is for you.

Table of Contents

  1. What Is Hyperemesis Gravidarum?
  2. HG vs Normal Morning Sickness
  3. Symptoms of HG
  4. Causes and Risk Factors
  5. When to Seek Help
  6. Treatment Options
  7. Coping with HG
  8. FAQ

What Is Hyperemesis Gravidarum?

Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy that can lead to:
  • Dehydration - inability to keep fluids down
  • Weight loss - 5% or more of pre-pregnancy weight
  • Electrolyte imbalances - dangerous changes in blood salts
  • Nutritional deficiencies - inability to absorb enough nutrients
  • Ketones in urine - a sign your body is breaking down fat for energy

HG affects approximately 1-3% of pregnancies - that's around 8,000-25,000 women in the UK each year. It's a real medical condition, not a sign of weakness, and it requires medical treatment.

A Brief History

HG has been documented for centuries. The phrase "hyperemesis gravidarum" comes from Greek: "hyper" (excessive), "emesis" (vomiting), and "gravidarum" (of pregnancy). Historically misunderstood as psychological, it's now recognised as a serious physiological condition.

HG vs Normal Morning Sickness

It's important to distinguish between normal morning sickness and HG:
Feature Normal Morning Sickness Hyperemesis Gravidarum
Vomiting frequency Occasional Multiple times daily
Ability to eat Reduced but possible Often impossible
Ability to keep fluids Usually possible Often impossible
Weight loss Minimal or none 5%+ of body weight
Dehydration Rare Common
Daily functioning Reduced but manageable Severely impaired
Need for treatment Lifestyle remedies Medical treatment needed
Hospital admission Rare May be required
Duration Weeks 6-14 Can last entire pregnancy

If you can't keep water down for 24 hours, can't eat anything, are losing weight, or feel dizzy and weak, you may have HG and need medical help.

Symptoms of HG

### Core Symptoms - **Severe nausea** - constant, unrelenting - **Vomiting 3+ times per day** - often much more - **Inability to keep food or water down** - **Weight loss** of 5% or more of pre-pregnancy weight - **Dehydration** - dark urine, infrequent urination, dry mouth

Associated Symptoms

  • Ketones in urine (detected by your midwife)
  • Dizziness or fainting
  • Extreme fatigue
  • Headaches (from dehydration)
  • Confusion or brain fog
  • Low blood pressure
  • Rapid heart rate
  • Vomiting bile (yellow-green fluid) when stomach is empty
  • Excessive saliva (ptyalism)
  • Depression and anxiety - HG takes a significant mental health toll

When Symptoms Are Dangerous

Seek urgent help if you experience:

  • Vomiting blood
  • Severe abdominal pain
  • Inability to keep any fluid down for 24 hours
  • Very dark urine or no urine for 8+ hours
  • Dizziness, confusion, or fainting
  • Rapid heartbeat
  • Chest pain

Causes and Risk Factors

### What Causes HG?

The exact cause isn't fully understood, but it's linked to:

  • hCG (human chorionic gonadotropin): Higher levels or higher sensitivity to hCG
  • Oestrogen: Rising levels may contribute
  • Thyroid hormones: hCG can stimulate the thyroid, causing temporary hyperthyroidism
  • Helicobacter pylori: Some evidence links this stomach bacteria to HG
  • Genetics: HG tends to run in families
  • GDF15 hormone: Recent research suggests this hormone, produced by the placenta, plays a key role in HG

Who's at Risk?

You're more likely to develop HG if:

  • You've had HG before (up to 80% recurrence in subsequent pregnancies)
  • Your mother or sister had HG
  • You're carrying multiples (twins or more)
  • You're carrying a girl (slight increased risk)
  • You have a history of motion sickness or migraines
  • You have a history of eating disorders (some studies suggest a link)
  • You're a first-time mother

When to Seek Help

### Contact Your GP If: - You can't keep food or water down for 12-24 hours - You're losing weight - Your urine is dark or you're urinating less - You feel dizzy, weak, or faint - You're vomiting 3+ times per day

Go to A&E or Call 999 If:

  • You're vomiting blood
  • You have severe abdominal pain
  • You can't keep any fluid down for 24+ hours
  • You're confused or very drowsy
  • You have chest pain or a very rapid heartbeat
  • You're severely dehydrated (no urine, dry mouth, sunken eyes)

Treatment Options

### Step 1: Lifestyle and Home Remedies

Before medication, try:

  • Small sips of fluid frequently rather than large drinks
  • Cold drinks (often easier to tolerate than hot)
  • Ice cubes or ice lollies to stay hydrated
  • Ginger (if tolerated - not everyone with HG can stomach it)
  • Acupressure wristbands (limited evidence but some women find them helpful)
  • Rest - fatigue makes nausea worse
  • Avoid triggers (smells, foods, movement)

Step 2: First-Line Medication

If lifestyle measures aren't enough, your GP can prescribe:

  • Cyclizine (Migraleve): Antihistamine-based anti-sickness
  • Promethazine (Avomine): Another antihistamine-based option
  • Prochlorperazine (Stemetil): Often combined with cyclizine
  • Combination therapy: Many women need two medications together

These are considered safe in pregnancy. Read our guide to anti-sickness medication in pregnancy for more detail.

Step 3: Second-Line Medication

If first-line doesn't work:

  • Ondansetron (Zofran): A stronger anti-sickness medication. Read our guide to ondansetron in pregnancy.
  • Metoclopramide (Maxolon): Another option, often combined with others
  • Domperidone: Sometimes used alongside other medications

Step 4: Hospital Treatment

If oral medications don't work, you may need:

  • IV fluids to treat dehydration
  • IV anti-sickness medication
  • Vitamin supplementation (especially thiamine)
  • Nutritional support in extreme cases

Most HG hospital stays are 1-3 days for rehydration and stabilisation. Some women need repeated admissions.

Ongoing Care

  • Regular monitoring by your midwife and GP
  • Urine testing for ketones
  • Weight monitoring
  • Blood tests for electrolytes and nutrition
  • Mental health support - HG is exhausting and isolating

Coping with HG

### Practical Tips
  • Ask for help - you can't do this alone
  • Accept offers of food, childcare, housework
  • Rest as much as possible
  • Keep a sick bowl with you at all times
  • Try different temperatures of food and drink
  • Cold foods smell less - try them first
  • Bland foods (plain rice, toast, crackers) may be tolerated
  • Sip fluids constantly rather than drinking large amounts

Emotional Support

  • Talk to someone - your partner, a friend, or a counsellor
  • Join an HG support group - Pregnancy Sickness Support is a UK charity specifically for HG
  • Be honest with your midwife about how you're coping
  • Don't feel guilty - HG is not your fault and not a sign of weakness
  • Consider speaking to your GP about mental health if you're struggling with depression or anxiety

Work and HG

  • Talk to your employer - you may need sick leave
  • Get a fit note from your GP if needed
  • Know your rights - you're protected from discrimination due to pregnancy
  • Don't push yourself - HG is a serious condition, not "just morning sickness"

Frequently Asked Questions

### How is HG different from normal morning sickness?

HG involves severe vomiting (3+ times daily), inability to keep food or water down, weight loss, and dehydration. Normal morning sickness is unpleasant but doesn't prevent you from eating and drinking enough to function.

How long does HG last?

For most women, HG eases around weeks 14-20, though some experience it throughout pregnancy. The worst period is typically weeks 8-12. A small percentage have symptoms until delivery.

Will I get HG in my next pregnancy?

HG has a high recurrence rate - approximately 55-80% of women who've had HG will have it in subsequent pregnancies. However, severity can vary between pregnancies.

Is HG dangerous for my baby?

With proper treatment, most babies of mothers with HG are born healthy. However, untreated severe HG can lead to complications, including low birth weight. This is why seeking treatment is crucial.

Can I take medication for HG in pregnancy?

Yes. There are several safe anti-sickness medications available on prescription for HG. These include cyclizine, promethazine, prochlorperazine, and ondansetron. Read our guide to anti-sickness medication in pregnancy for details.

Further reading:

This article is for informational purposes only and does not constitute medical advice. Always consult your GP or midwife with any concerns about your pregnancy.

Last reviewed: June 2026

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