Hyperemesis Gravidarum: When Pregnancy Sickness Is Severe

✓ This content has been medically reviewed by an obstetrician and gynaecologist
Written & medically reviewed by: Op. Dr. Ayşet Jane Özcan, Obstetrics & Gynaecology Specialist
Istanbul Faculty of Medicine · Medical Park Bahçelievler · TJOD and TSRM member
Last updated: 15 October 2026 · Last medical review: 15 October 2026

Almost every pregnancy book tells you that morning sickness is normal, that it passes by twelve weeks, and that dry crackers by the bed will help. For most women that is roughly true. For a small number it is not true at all. If you are vomiting so often that you cannot keep a mouthful of water down, if you are losing weight instead of gaining it, if you have stopped going to work and stopped leaving the house, then what you have is not ordinary pregnancy sickness and you should not be managing it alone with crackers.

This article is about hyperemesis gravidarum: what it is, how it is told apart from normal morning sickness, how severity is actually measured in a clinic, the warning signs that mean you need to be seen the same day, what treatment involves, what genuinely helps at home and what does not, what it means for your baby, when it usually settles, and whether it is likely to happen again. I have written it the way I would explain it to you sitting in my consulting room — plainly, and without pretending it is easier than it is.

What hyperemesis gravidarum actually is

Hyperemesis gravidarum is the severe end of pregnancy nausea and vomiting — severe enough that you cannot keep food or fluid down, you lose weight, and your body becomes short of fluid and salts. It is a recognised medical condition with a definition, an assessment pathway and a treatment ladder. It is not simply a bad case of morning sickness.

Nausea and vomiting in early pregnancy is extremely common; the large majority of pregnant women get some of it. Hyperemesis gravidarum is much less common, affecting roughly one to three in every hundred pregnancies. The distinction matters because the two are managed completely differently. Ordinary pregnancy sickness is uncomfortable and is handled with reassurance, meal timing and sometimes a simple anti-sickness tablet. Hyperemesis gravidarum can leave you unable to work, unable to care for other children, and medically unwell. It needs active treatment.

In practice the diagnosis is reached when three things are present together and nothing else explains them: persistent nausea and vomiting that began in early pregnancy and stops you eating and drinking normally; weight loss compared with your weight before pregnancy, with the figure usually quoted being a loss of about five per cent or more; and evidence that your body is running short of fluid and electrolytes — dehydration on examination, or abnormal blood sodium and potassium. Being unable to carry on with ordinary daily life is part of the definition, not an optional extra.

Why "nothing else explains them" matters

Vomiting in pregnancy is not automatically hyperemesis. A urinary tract infection, gastroenteritis, gallbladder disease, an overactive thyroid, severe reflux, and a molar or multiple pregnancy can all produce a similar picture, and each needs different treatment. That is why a proper assessment includes a urine test, blood tests and usually a scan, rather than a label handed out over the telephone.

One further point, because it still comes up. Hyperemesis gravidarum is not psychological in origin. It is not caused by anxiety, by a difficult relationship, or by mixed feelings about being pregnant. That idea belongs to the medical writing of several decades ago and it has caused real harm. Severe sickness causes low mood. Low mood does not cause severe sickness.

Hyperemesis gravidarum symptoms: what it looks and feels like

The defining symptom is nausea that does not let up — nausea that is still there after you vomit, still there when you wake, and still there when your stomach is empty — combined with vomiting frequent enough that nothing stays down. Women describe it as constant seasickness that never ends, not as feeling queasy in the morning.

Alongside the nausea and vomiting, the picture usually includes several of the following:

• Vomiting many times a day, often including retching and dry heaves when there is nothing left to bring up
• Inability to keep down even small sips of water, let alone food or tablets
• Weight loss rather than the slow weight gain expected in early pregnancy
• A dramatically heightened sense of smell, so that cooking, perfume, toothpaste, a partner's deodorant or the inside of a refrigerator triggers vomiting
• Excess saliva that you cannot swallow (ptyalism), sometimes needing to be spat out
• Severe fatigue and muscle weakness — climbing the stairs becomes a decision
• Light-headedness when you stand, headache, and a dry mouth
• Heartburn and acid reflux, which make the vomiting worse in a loop
• Constipation, from low fluid and food intake and sometimes from medication
• Sleep that is broken by nausea, so you are never rested
• Not being able to work, drive, shop, cook, or care for your other children

Symptoms that tell you it is more than discomfort

Three features in particular push a case from "significant pregnancy sickness" into the territory that needs medical review: you are not keeping fluids down for more than about eight to twelve hours; the scales are going down; and you are producing much less urine than usual, or urine that is dark. Those three together mean dehydration is building, and dehydration is what makes you genuinely unwell.

Timing is also part of the symptom picture. Hyperemesis almost always begins early — typically between four and seven weeks, usually before nine weeks — and tends to be at its worst around nine to twelve weeks. Nausea and vomiting that starts fresh after about nine weeks is unusual for hyperemesis and should prompt a search for a different explanation, such as a urinary or kidney infection, gallbladder inflammation, gastroenteritis, an overactive thyroid, pancreatitis, a molar pregnancy, or — in later pregnancy — preeclampsia.

Hyperemesis gravidarum vs morning sickness: how to tell the difference

The simplest way to separate them is not how unpleasant the nausea feels, but whether you are still able to eat, drink and function. Morning sickness makes you miserable. Hyperemesis gravidarum makes you unable to keep yourself hydrated and nourished, and that is a different problem.

Ordinary nausea and vomiting of pregnancy

With ordinary morning sickness, nausea often comes in waves and tends to be worse at certain times of day or on an empty stomach. You may vomit, but usually feel some relief afterwards. Between the waves you can eat something, even if your choices have narrowed to toast and apples. Your weight holds steady or creeps up. You can usually still go to work, even on a bad day. It settles for most women during the second trimester, and simple measures plus occasionally a tablet are enough.

Hyperemesis gravidarum

With hyperemesis, the nausea is continuous rather than wave-like, and vomiting brings no relief because the nausea was never caused by what was in your stomach. Oral fluid intake fails — you vomit the water back. Weight falls. Your urine becomes dark and scanty. Your blood tests become abnormal: low potassium, low sodium, sometimes mildly deranged liver enzymes or thyroid tests. Normal life stops. Simple home measures do not touch it, and tablets taken by mouth may not stay down long enough to be absorbed.

The part people get wrong

Severity is not just about the number of vomits. Some women with hyperemesis vomit relatively few times a day but have relentless nausea and cannot drink — and they are just as dehydrated as someone vomiting fifteen times. Conversely, vomiting once each morning and then eating a normal lunch is not hyperemesis. What is being judged is the overall state of your hydration, your weight and your ability to function, which is exactly what the formal scoring systems below try to capture.

It is also worth saying that you do not need to meet a strict definition to deserve treatment. If pregnancy sickness is stopping you living your life, that is a reason to be seen, whatever label ends up on the notes.

Why it happens, and who is more likely to get it

Hyperemesis gravidarum is driven by the hormonal and placental changes of early pregnancy, not by anything you did or failed to do. The mechanism is not completely settled, but the main threads are now reasonably clear.

Pregnancy hormones are central. Levels of human chorionic gonadotrophin (hCG) rise steeply in the first trimester and peak at roughly the same time as the sickness peaks, which is why conditions with higher hCG — twins and higher-order multiples, and molar pregnancy — carry a higher chance of severe sickness. Oestrogen and progesterone contribute by slowing the stomach and relaxing the valve at the top of it, which worsens reflux and the sense of fullness. More recent research has focused on a placental hormone called GDF15, which acts on the brainstem area that controls nausea and vomiting, and on inherited differences in how sensitive a woman is to it. That line of work is a good explanation for why hyperemesis so clearly runs in families.

Factors that raise the chance

• Hyperemesis gravidarum in a previous pregnancy — the strongest single predictor
• A mother or sister who had severe pregnancy sickness
• Twins or a higher-order multiple pregnancy
• Molar pregnancy
• A history of motion sickness, migraine, or nausea with hormonal contraception
• Carrying a female fetus, which is associated with a slightly higher chance at population level but tells you nothing useful about your own pregnancy
• Pre-existing conditions that make nausea worse, such as reflux disease or an overactive thyroid

And some things that are not causes, despite what you may be told: being underweight or overweight before pregnancy does not cause it, a stressful job does not cause it, and neither does an unplanned pregnancy. Equally, there is nothing you can take in advance that reliably prevents it. If you have had it before, however, the plan can be made before symptoms peak — which is covered further down.

About the fetal sex question, since it is one of the most searched: the association is real but weak, and it is a statistical pattern across thousands of pregnancies. Severe sickness is not a way of finding out whether you are carrying a girl.

How severe sickness is assessed: PUQE scoring, weight and blood tests

Severity is assessed with a combination of a symptom score, your weight compared with before pregnancy, how dehydrated you are on examination, and blood tests — not by how distressed you look in the waiting room. Having objective measures matters, because it is what gets you treated properly rather than reassured and sent home.

The PUQE score

The most widely used tool is the PUQE score — Pregnancy-Unique Quantification of Emesis and nausea. It asks three questions about the previous twenty-four hours: for how many hours in total have you felt nauseated; how many times have you vomited; and how many times have you retched or had dry heaves without bringing anything up. Each answer scores from one to five, giving a total between three and fifteen. Broadly, a score of six or below is considered mild, seven to twelve moderate, and thirteen or above severe. The score is usually repeated at each review, so the effect of treatment can be judged against something other than memory. Some units use a second scoring tool as well, which adds questions about eating, drinking and daily functioning to the symptom count.

Many clinicians add a simple question that the score does not contain: on a scale of nought to ten, how is your quality of life compared with before pregnancy? That one answer often changes the management plan more than the number does.

Weight, urine and blood

Your current weight is compared with your pre-pregnancy weight, so it is worth knowing that figure or bringing an old record. A urine dipstick is checked, chiefly for signs of infection. Ketones may be looked at too — they appear when the body is burning fat for fuel because no food is going in — but they are no longer used to judge how severe the sickness is, because they correlate poorly with how unwell a woman actually is. In other words, a negative dipstick is not reassurance in someone who is clearly dehydrated. Severity is judged on the symptom score, your weight, your clinical state of hydration and your blood results. Blood tests typically include sodium and potassium, kidney function, a full blood count, liver enzymes, thyroid function and glucose. Low potassium and low sodium are the findings that most often change management. Mildly raised liver enzymes and a mildly abnormal thyroid result are common consequences of severe vomiting rather than separate diseases, and they usually settle as the sickness settles — they rarely need treatment in their own right.

Imaging and the rest of the picture

An ultrasound scan is usually arranged to confirm the pregnancy is in the womb and developing, to check whether there is more than one baby, and to exclude a molar pregnancy. A mid-stream urine sample is sent to rule out a urinary infection, which is a common and easily missed trigger for vomiting. From that point onwards, severe sickness is woven into your regular pregnancy follow-up, with weight and symptom scores tracked at each visit rather than assessed once and forgotten.

Dehydration warning signs: when to seek help the same day

The single most useful rule is this: if you have been unable to keep fluids down for more than about eight to twelve hours, you need to be assessed that day rather than waiting to see if tomorrow is better. Dehydration in hyperemesis builds quietly and then causes problems quickly.

Signs that you are becoming dehydrated:

• Passing much less urine than usual, or urine that is dark and strong-smelling
• Not having passed urine at all for eight hours
• Dizziness or feeling that you might faint when you stand up
• A heart that feels fast or pounding at rest
• A dry mouth, cracked lips, sunken eyes, or skin that stays pinched when you lift it
• Headache that will not shift
• Marked weakness, or feeling too unsteady to walk safely

Seek urgent care straight away if

• You are confused, drowsy, or difficult to rouse
• You have double vision, jerky eye movements, or you cannot walk in a straight line — this combination can signal thiamine (vitamin B1) deficiency affecting the brain, which is uncommon but a genuine emergency
• You are vomiting blood, or material that looks like coffee grounds
• You have severe abdominal pain, particularly if it is one-sided, or pain with shoulder-tip discomfort — which is not typical of hyperemesis and overlaps with the symptoms of an ectopic pregnancy
• You have a fever, or pain and burning when passing urine
• You have vaginal bleeding; any bleeding during pregnancy alongside severe vomiting should be assessed rather than attributed to the sickness
• You have lost a large amount of weight, or the scales keep falling week on week

What to do while you arrange to be seen

Do not try to drink a large glass of water to catch up; a big volume reliably comes straight back. Small, cold, salt-containing sips are the only thing worth attempting — the detail is in the home-measures section below. If even that fails, stop trying and go in. At that point the problem is no longer something oral fluids can fix, and continuing to force them simply delays the treatment you need.

Treatment: fluids, anti-sickness medication and thiamine

Treatment has three parts that run in parallel: replacing fluid and salts, protecting you against vitamin B1 deficiency, and suppressing the nausea and vomiting with medication stepped up until it works. The aim is to get you drinking, eating and functioning again, and to keep you out of the cycle where vomiting prevents you absorbing the very tablets meant to stop it.

Rehydration

If you cannot keep fluids down, they are given into a vein. The usual choice is a salt-containing solution, with potassium added when blood levels are low. Glucose-containing fluids are deliberately avoided as the first fluid in severe vomiting, because giving glucose to someone who is thiamine-depleted can precipitate the brain complication mentioned earlier. Sodium levels that are very low are corrected gradually rather than quickly, for safety. Blood tests are repeated to confirm the salts are coming back into range.

Thiamine

Anyone who has been vomiting for several weeks needs thiamine (vitamin B1) replacement, by mouth if tolerated and into a vein if not. This is not optional extra care — it is how the neurological complication of prolonged vomiting is prevented, and it is given before or with any glucose.

Anti-sickness medication, by class

Several classes are used in pregnancy, and the approach is to start with the longest-established and add or switch if symptoms persist. Described by class rather than by brand:

• Antihistamines (H1 antagonists) — the most commonly used first step, including the vitamin B6 and antihistamine combination licensed for pregnancy sickness in many countries
• Phenothiazines — a long-established group acting on dopamine and other receptors
• Dopamine antagonists and prokinetics — these also speed up stomach emptying; one of them is limited to a short course because of the risk of movement side effects
• 5-HT3 receptor antagonists — effective for nausea and widely used, with the first-trimester safety data discussed with you individually before prescribing
• Corticosteroids — reserved for sickness that has not responded to the above, and prescribed under specialist supervision

Routes matter as much as drugs. If you cannot keep tablets down, the same medication can often be given by injection, into a vein, or as a suppository. If a drug appears not to work, the first question is always whether it was actually absorbed.

The supporting measures that are easy to forget

Reflux and heartburn make vomiting worse, so acid-suppressing medication is routinely added. Constipation is treated, because straining and discomfort feed the nausea. Vitamin and folic acid supplementation is continued in whatever form you can tolerate. If you are admitted, blood-clot prevention is considered, since dehydration plus lying still raises that risk. Nothing here should be a personalised plan you take from an article — doses and choices belong in a consultation with the doctor who has your blood results in front of her.

When hospital admission is needed, and what happens there

Admission is for women who are still vomiting despite anti-sickness tablets taken by mouth, who continue to lose weight or remain clinically dehydrated, or who are too unwell to be managed at home. It is also appropriate when there is another condition alongside the sickness, such as an infection that needs antibiotics you cannot swallow.

Many units now offer a middle option before full admission: a day unit or ambulatory care pathway where you come in, receive intravenous fluids, electrolytes, thiamine and injected anti-sickness medication over several hours, and go home the same evening with a prescription. For a lot of women this is enough, and it avoids a hospital stay.

What inpatient care involves

• Intravenous fluids with potassium and sodium adjusted to your blood results
• Anti-sickness medication given by a route that bypasses your stomach
• Thiamine replacement
• Daily weight, fluid balance charting and repeat bloods
• Treatment of reflux and constipation
• Assessment for blood-clot prevention
• A quiet single room where possible, because ward smells and food trolleys are genuinely triggering

If vomiting continues for a long time

A small number of women remain unable to eat for weeks. In that situation nutrition becomes the priority and a dietitian is involved. Feeding through a fine tube passed into the stomach or small bowel can be used, and feeding directly into a vein is reserved for the rare cases where the gut route is not possible. These are specialist decisions, made jointly, and they are not a sign that anything has gone wrong with your care — they are what is available when sickness is prolonged.

Being taken seriously

If you are told that severe sickness is normal and sent home still unable to drink, it is reasonable to come back and to ask for your weight, your symptom score, your state of hydration and your blood electrolytes to be checked and written down. Objective numbers change conversations. Keeping a simple diary of how much you drank, how much you vomited and how much urine you passed over twenty-four hours is also worth more than you would think at an appointment.

What you can try at home, and what does not work

Home measures cannot cure hyperemesis gravidarum, but the right ones make the hours more bearable and can keep you drinking just enough to stay out of hospital. I want to be honest about the limits, because being handed a list of lifestyle tips when you are vomiting ten times a day is its own kind of insult.

Worth doing

• Sip tiny volumes constantly rather than drinking glasses — a teaspoon or a mouthful every few minutes adds up, and large volumes come back
• Use cold drinks, ice chips, or ice lollies made from an oral rehydration solution rather than plain water, since you are losing salts as well as fluid; cold has less smell and is often better tolerated
• Try sour, salty or plainly flavoured fluids if sweet ones are intolerable
• Eat whatever you can keep down, in very small amounts, often, and do not worry for now about whether it is balanced — bland dry carbohydrate and cold foods are the usual survivors
• Have someone else cook, and eat away from the kitchen; strong smells are frequently the trigger rather than the food itself
• Separate drinking from eating by twenty or thirty minutes, so your stomach is never full of both
• If your combined pregnancy multivitamin makes you vomit, speak to your doctor about taking folic acid on its own instead; the iron in many prenatal preparations is a common aggravator
• After vomiting, rinse your mouth with water or a teaspoon of bicarbonate of soda in water and wait before brushing, to protect tooth enamel from the acid
• Rest flat in a cool, dark, quiet room when the nausea peaks, and accept that lying still is treatment, not laziness
• Take sick leave. Trying to work through hyperemesis usually ends in a worse crash

What does not work, or is not enough

Ginger, in capsules, tea or biscuits, has some evidence in mild to moderate pregnancy nausea and is harmless to try — but it does not treat hyperemesis, and being offered it as the answer wastes time. Acupressure wristbands have inconsistent evidence; use them if they help you, but do not rely on them. Vitamin B6 alone may take the edge off mild nausea and is more useful in combination with an antihistamine.

Three things are actively unhelpful. The first is "pushing through" and waiting it out: dehydration and weight loss do not reward willpower. The second is stopping your anti-sickness medication as soon as you feel slightly better — symptoms usually rebound, and it is better to come down slowly with advice. The third is cannabis, which is sometimes suggested online as an anti-nausea remedy; it is not safe in pregnancy, and regular use can itself produce a severe cyclical vomiting syndrome that is easily mistaken for hyperemesis and will not improve until it is stopped. Unregulated herbal preparations are similarly best avoided, since you cannot know what is in them.

Does hyperemesis gravidarum affect the baby?

In the great majority of cases the baby is born healthy, and hyperemesis gravidarum is not associated with an increased risk of miscarriage — if anything, nausea and vomiting in pregnancy is linked with a lower risk. The risks that do exist relate to sustained undernutrition and dehydration in the mother, which is precisely why the sickness is treated rather than endured.

In early pregnancy the baby's nutritional needs are tiny and are met from your reserves, so a few weeks of being unable to eat does not starve the fetus. Where there is a measurable effect, it is in pregnancies with severe, prolonged weight loss that continues well beyond the first trimester: those carry a somewhat higher chance of the baby being smaller than expected at birth, and of earlier delivery. That is a reason to treat the sickness vigorously and to monitor growth, not a reason to assume harm.

The risks that matter most are to you

The serious complications of hyperemesis are maternal: significant electrolyte disturbance, thiamine deficiency affecting the brain, tears in the lining of the oesophagus from forceful vomiting, dental enamel erosion, blood clots from dehydration and immobility, and the psychological toll discussed below. Looking after you is how the pregnancy is looked after.

Medication and the baby

This is the question I am asked most often, usually with real guilt attached. The anti-sickness classes used in pregnancy have been in use for decades and are chosen specifically because they have reassuring records in pregnancy; where a particular drug carries a question mark in the first trimester, the discussion is had with you openly and the decision is individual. The alternative to treatment is not a risk-free pregnancy — it is a pregnancy with a dehydrated, undernourished mother, and that is not the safer option. If you have been prescribed something and then read something alarming, bring it to your appointment rather than quietly stopping it.

Growth monitoring

If weight loss has been substantial or the sickness has run on into the second half of pregnancy, growth scans are usually added to your antenatal schedule so the baby's size and the amount of fluid can be followed. In most cases they are entirely normal, and the extra checks are for peace of mind as much as anything else.

When it settles, and whether it comes back next time

For most women the worst passes between weeks fourteen and twenty, with the peak around nine to twelve weeks; a minority have symptoms that continue to some degree until delivery. Improvement is usually gradual and uneven rather than a clean switch — good days appear first, then good mornings, then a week where you notice you have stopped counting.

Recovery takes longer than the vomiting does. Appetite returns before strength does, and many women feel physically depleted for weeks after the sickness has gone, which is normal and worth expecting rather than being alarmed by. Weight catches up in the second half of pregnancy. If you remain unable to eat properly past twenty weeks, that warrants review rather than patience.

As pregnancy continues, attention shifts to the usual monitoring — blood pressure, urine, growth. It is worth knowing the signs of preeclampsia for later pregnancy, because having had severe sickness early does not exempt you from anything else, and new vomiting in the third trimester with headache or upper abdominal pain is a different problem that needs same-day assessment.

Will it happen again?

Having had hyperemesis gravidarum is the strongest known predictor of having it in a future pregnancy. A large proportion of women who had it do experience it again, although by no means all, and the severity can differ from one pregnancy to the next. There is no test that will tell you in advance.

What can be done is to plan. If you are thinking about another pregnancy, it is worth an appointment before you conceive, so that a plan exists on paper. That plan usually includes: booking early with the pregnancy care team rather than waiting; starting an anti-sickness medication at the first sign of nausea rather than waiting for it to become severe, since getting ahead of it is easier than catching up; knowing in advance which day unit or service to contact and not having to negotiate it while vomiting; arranging practical help at home and time off work from the start; and keeping a record of which medications and routes helped last time, which is often the single most useful piece of information you can bring.

Finally, it is entirely reasonable for severe sickness to influence whether and when you have another pregnancy. That is a legitimate thing to weigh up, and a legitimate thing to talk about with your doctor rather than alone.

The mental health side, and how to ask for support

Hyperemesis gravidarum takes a real psychological toll, and feeling low, anxious, trapped or detached from the pregnancy is a consequence of being ill for months — not a character flaw and not a sign that you do not want your baby. I raise it with every woman I treat for severe sickness, because almost nobody raises it first.

What women describe is fairly consistent: exhaustion that empties out everything you used to enjoy; guilt about not feeling the way pregnancy is supposed to feel; guilt about other children; isolation, because you have stopped seeing people and the people you do see keep telling you morning sickness is normal; fear of eating, drinking or moving in case it triggers vomiting; and sometimes intrusive, frightening thoughts about not being able to continue. Some women are left with lasting anxiety about pregnancy afterwards, and symptoms resembling post-traumatic stress are recognised following severe hyperemesis.

What helps

• Saying it out loud at an appointment. Low mood changes how urgently sickness is escalated, so it is clinical information, not a complaint
• Being screened properly for depression and anxiety rather than asked in passing, and being referred to perinatal mental health services where they exist
• Bringing your partner or a family member to an appointment, so someone else understands what the condition is and stops offering ginger biscuits
• Practical help that removes triggers: someone else cooking, shopping and managing the other children
• Contact with others who have had it — patient support organisations for severe pregnancy sickness exist in many countries and reduce the isolation considerably
• Continuing to treat the sickness aggressively, because mood tends to lift as the vomiting comes under control

If you reach the point where you feel you cannot continue the pregnancy, say so to your doctor directly. That statement is not something to be ashamed of and it is not an argument to be talked out of — it is a signal that treatment has not yet been adequate, and it should change how urgently and how intensively you are treated. And if you are having thoughts of harming yourself, that needs same-day help, not an appointment next month.

Severe pregnancy sickness is one of those conditions where good care is mostly a matter of being believed early. If you feel you are not being heard, it is reasonable to ask for a second opinion, and ongoing women's health care should include someone who knows your history and takes it seriously from the first visit of the next pregnancy.