Hyperemesis gravidarum (HG) is the severe end of pregnancy sickness — persistent, excessive nausea and vomiting that stops you keeping food or fluids down, leading to dehydration, weight loss and disruption of daily life. It is not “just bad morning sickness” but a recognised medical condition that often needs treatment and sometimes hospital admission. With proper care the outlook for mother and baby is generally good, but the key is to seek help early rather than trying to ride it out at home.
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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.
Not keeping any fluids down, passing little or dark urine, feeling very dizzy or faint, losing weight, or vomiting blood needs urgent assessment — contact your maternity unit or go to hospital. Call 995 for collapse.
How it differs from morning sickness
Ordinary nausea and vomiting of pregnancy is very common — affecting around three in four pregnant women (per HealthHub and RCOG) — and, though unpleasant, usually lets a woman keep enough food and fluid down; it typically starts around weeks four to seven and eases for most by about weeks 14 to 20. HG is reported to affect roughly one to three in every 100 pregnancies (per NHS and RCOG estimates). The distinction is not about how “tough” you are: HG involves relentless vomiting that causes real dehydration and weight loss, and it deserves medical treatment.
What causes it
The exact cause is unknown, but it is widely thought to be linked to the rapid hormonal changes of pregnancy. Commonly cited risk factors include HG in a previous pregnancy, a multiple pregnancy such as twins, a family history, a first pregnancy, and a history of severe motion sickness or migraine. Importantly, it is not caused by anything you did or ate, so there is no reason for guilt or blame.
Symptoms
The main features are prolonged, severe nausea and repeated vomiting many times a day, being unable to keep food or drink down, signs of dehydration, and weight loss. Many women also feel tired, faint, light-headed or dizzy, may have a faster heart rate or low blood pressure, and produce a lot of saliva. The impact on mood, work, relationships and daily life is common and real, and worth raising with your care team.
Red flags
Contact your maternity unit, GP or hospital urgently if you cannot keep any fluids down for a prolonged period, are passing very little or dark urine or none for many hours, feel very dizzy or faint (especially on standing), are losing weight, or are vomiting blood or bringing up brown, coffee-ground material. Severe weakness, confusion, a racing heartbeat, or a high temperature with tummy pain also need prompt care, and collapse or severe breathing difficulty is a 995 emergency. Dehydration in pregnancy should never be “waited out” at home.
How it is assessed and treated
Tell your obstetrician, GP or midwife early rather than self-diagnosing. Assessment may include checking hydration, weight and blood pressure, a urine test for dehydration, and blood tests for salts and kidney function, while excluding other causes of vomiting. Care is usually led by an obstetrician, and severe cases are managed in hospital. For milder symptoms, self-care may help — rest, small, frequent, bland meals, sipping fluids little and often, eating something dry such as plain crackers before getting up, avoiding strong smells and greasy food, and, for some women, ginger. When self-care is not enough, several anti-sickness medicines are considered suitable in pregnancy and may be prescribed — these must be doctor-directed, and you should not start or stop medication on your own; this guide gives no doses. Hospital care for HG may include intravenous (drip) fluids to correct dehydration, intravenous anti-sickness medicine, and monitoring of salts and nutrition until the vomiting settles. Most women improve with treatment.
Looking after yourself through it
Beyond medical treatment, a few practical steps help you cope while HG runs its course. Keep sipping small amounts of fluid frequently even when it feels difficult, as staying even partly hydrated matters, and try cold or bland foods, which are sometimes easier to tolerate than hot or strong-smelling ones. Rest as much as you can, since tiredness worsens nausea, and accept help with work and household tasks — HG is a genuine illness, not weakness. The emotional toll can be heavy, so tell your care team if you are struggling, and lean on your partner, family or a support group. Keep a simple note of what you can keep down and how often you are being sick, which helps your team judge whether treatment needs stepping up. For many women symptoms ease by around weeks 15 to 20, though some have them for longer, and your team can help manage them in the meantime.
When to see a doctor
See a doctor if nausea and vomiting are severe, frequent, stopping you eating or drinking normally, or affecting daily life, rather than assuming it is normal morning sickness — and seek urgent care for any red flag such as not keeping fluids down, dark or scanty urine, dizziness, weight loss or vomiting blood. Attend your antenatal appointments so your pregnancy is monitored throughout.
Related pregnancy & women’s-health topics
- Placenta praevia
- Placental abruption
- Group B streptococcus
- Cholestasis of pregnancy
- Pelvic girdle pain
- Anaemia in pregnancy
- Preterm labour
- Gestational hypertension
- UTI in pregnancy
- Pre-eclampsia
- Obstetricians & gynaecologists
Sources
- NHS — Severe vomiting in pregnancy (hyperemesis gravidarum): nhs.uk
- RCOG — Pregnancy sickness and hyperemesis gravidarum: rcog.org.uk
- HealthHub (Singapore) — Morning Sickness: Should You Be Worried?: healthhub.sg
- SingHealth / HealthXchange — Hyperemesis Gravidarum: healthxchange.sg