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Hyperemesis Gravidarum

A severe form of pregnancy nausea and vomiting affecting around 1 to 3 in every 100 pregnancies12, leading to dehydration, electrolyte imbalance, ketosis and weight loss greater than 5% of pre-pregnancy weight1. A biological condition linked to the pregnancy hormone GDF15, not a psychological one. Being unable to keep food or fluids down for 24 hours needs same-day help from your midwife or doctor, and confusion or signs of shock need emergency care11.

Hormonal & Women's Health Evidence-Based

Last updated:

โš ๏ธ Medication safety: please read first. The nutrition and supplement approaches on this page are meant to work alongside your prescribed treatment, never to replace it. Never stop, reduce or change your anti-nausea medication without your prescriber's guidance. Doing so can be dangerous. Some supplements are not safe in pregnancy, so talk to your prescriber, midwife or pharmacist before starting anything on this page.
Definition

What Is Hyperemesis Gravidarum?

Hyperemesis gravidarum (HG) is a severe form of pregnancy nausea and vomiting that causes dehydration, electrolyte disturbance, nutritional deficiency, ketosis and weight loss greater than 5% of pre-pregnancy weight, with significant impact on daily function.

HG has been linked to GDF15 (growth differentiation factor 15), a hormone from the baby and placenta that acts on the brainstem; women whose levels were low before pregnancy are more sensitive to it2. It is a biological condition, not a psychological one.

HG severity is most often assessed using the PUQE (Pregnancy-Unique Quantification of Emesis) score, a validated scale scored from 3 to 15.8 Severity levels are described below:

Hyperemesis gravidarum, a pregnant woman with severe nausea, vomiting, dehydration and weight loss

Mild Nausea and Vomiting of Pregnancy (NVP, PUQE 3 to 6)

Common "morning sickness." Nausea most days, occasional vomiting, able to eat and drink, weight stable or modest loss less than 5%. Affects around 8 in 10 pregnancies and usually improves by 12 to 20 weeks12. Manageable with diet, ginger, vitamin B6 and rest.

  • โ†’Hallmarks: Daily nausea, 0 to 2 vomiting episodes/day, retains 50% or more of fluids/food
  • โ†’Primary lever: Bland small frequent meals, ginger, vitamin B6, hydration, rest, acupressure

Moderate Nausea and Vomiting of Pregnancy (PUQE 7 to 12)

Significant impact on daily life. Vomiting 3 to 5 times/day, nausea nearly constant, difficulty eating or drinking, weight loss approaching the 5% of pre-pregnancy weight that marks HG1. Outpatient anti-nausea medicine (anti-emetics) and IV fluids are often needed.

  • โ†’Hallmarks: Vomiting 3 to 5×/day, persistent nausea, weight loss 2 to 5%
  • โ†’Primary lever: Prescription anti-nausea medicines (doxylamine + B6, ondansetron4, promethazine), outpatient IV fluids

Severe HG (PUQE 13 to 15) / Hospitalization Required

Unable to keep down any fluids, vomiting more than 5×/day, weight loss greater than 5% of pre-pregnancy weight, ketosis, dehydration, electrolyte disturbance. Requires hospital admission for IV fluids, IV anti-nausea medicines and electrolyte correction. Risk of Wernicke's encephalopathy from thiamine deficiency3.

  • โ†’Hallmarks: Inability to retain any oral intake, weight loss > 5%, tachycardia, dry mucous membranes
  • โ†’Primary lever: Hospital admission, IV thiamine before glucose, IV fluids, IV anti-nausea medicines, electrolyte replacement6

Refractory / Persistent HG (beyond 20 weeks)

HG that persists beyond 20 weeks, sometimes through the entire pregnancy, or that requires escalating therapy including continuous subcutaneous infusion of anti-nausea medicine, nutrition through a long IV line (a PICC line) or a feeding tube passed through the nose into the small intestine (an NJ tube). HG often recurs in later pregnancies, which is why a plan made in advance matters.

  • โ†’Hallmarks: Symptoms beyond 20 weeks, failure of standard therapy, ongoing weight loss, malnutrition
  • โ†’Primary lever: Multidisciplinary team (maternal-fetal medicine, gastroenterology, nutrition, mental health); enteral or parenteral nutrition
By the Numbers

Hyperemesis Gravidarum by the Numbers

1 to 3 in 100
pregnancies are affected by HG, an estimate because some cases go unreported; it often needs hospital treatment12
24%
of later pregnancies had HG again in Finnish national data on 1,836 women; published recurrence figures range from 15 to 81%18
33%
of women with HG reported a mother with severe pregnancy sickness, against 7.7% of controls, and their sisters had a much higher risk19
41.2%
of women with HG taking prescribed medicine had to ask for it themselves, in a UK survey of 5,071 20
4.9%
had ended a wanted pregnancy because of HG, and a further 52.1% had considered it, in the same survey20
7 weeks
median length of vomiting before Wernicke's encephalopathy in 177 reported cases in HG; lasting cognitive problems followed in 65.4%, and thiamine prevents it14
Signs & Symptoms

Symptoms of Hyperemesis Gravidarum

Distinguishing HG from normal NVP guides timely treatment and prevents complications like dehydration, electrolyte disturbance and Wernicke's encephalopathy.

SymptomWhat happens
Gastrointestinal & Eating Symptoms
Persistent Vomiting (more than 3×/day)Vomiting that occurs throughout the day, not just in the morning, and continues even when the stomach is empty (dry heaves, bile).
Continuous Nausea (Day & Night)Unrelenting nausea that does not improve with an empty stomach, food or rest. Triggered or worsened by smells, motion, brushing teeth, opening the refrigerator or sometimes by nothing identifiable.
Inability to Tolerate FluidsEven small sips of water trigger vomiting. This is the threshold sign of true HG and the indication for IV fluids. Try a teaspoon of plain water; if it cannot be retained, outpatient or inpatient hydration is needed.
Significant Weight Loss (> 5%)Loss of more than 5% of pre-pregnancy weight (e.g., 7.5 lb (3.4 kg) for a 150 lb (68 kg) woman) is a diagnostic criterion for HG.
Food Aversions & Hypersensitivity to SmellsSmell of cooking food, perfume, garbage, soap or even your partner's deodorant becomes intolerable. Foods previously loved trigger immediate nausea.
Systemic & Complication Signs
Dehydration SignsDry mouth and lips, sunken eyes, decreased skin turgor, reduced urine output (less than 4×/day), dark concentrated urine, dizziness on standing, rapid pulse, headache.
Electrolyte Imbalance SymptomsMuscle weakness, cramps, palpitations, confusion and, rarely, cardiac arrhythmia can result from low potassium, sodium or magnesium.
Wernicke's Encephalopathy Warning SignsConfusion, abnormal eye movements (nystagmus), unsteady gait and memory changes from thiamine (B1) deficiency. Rare but catastrophic if missed. Any IV fluids given to a woman with HG must include or be preceded by thiamine.
Depression & IsolationHG profoundly affects quality of life. Ask to be screened for depression and PTSD; both are common during and after HG.
โš ๏ธ Get help now: call 911 or go to the emergency department (or call 999 in the UK) if you are vomiting and your skin, lips or tongue look blue, gray, pale or blotchy, your skin feels cold, you breathe fast or with difficulty, or you are unusually sleepy or hard to wake, which can mean shock13; or for confusion, double or blurred vision or unsteadiness, which can signal thiamine deficiency14; or if you vomit blood. Get urgent same-day help from your midwife or doctor (NHS 111 in the UK) if you cannot keep food or fluids down for 24 hours; have not peed for 8 hours or have very dark urine; feel very weak, dizzy or faint; have abdominal pain or a high temperature; or have lost weight11. HG is treatable; do not wait until you are critically ill.
Causes

Causes of Hyperemesis Gravidarum

HG is a biological condition of pregnancy, not something caused by how a woman copes, and it is treated with prescribed medicine and fluids12.

CauseHow It Contributes to Hyperemesis GravidarumWhat Helps
GDF15, a hormone from the pregnancyMost GDF15 in the mother's blood comes from the baby and placenta; higher levels in pregnancy, and lower levels before pregnancy, both raise the risk of HG2Prescribed anti-nausea medicine, with a second medicine added or combined when the first is not enough, as the treatment section sets out15
Family history and HG beforeHG runs in families, so a mother or sister who had it raises the chance, and it is more likely after HG in a previous pregnancy12A plan made before the next pregnancy: rest and child care arranged, and a talk with your doctor about starting medicine early12
Twins or more, and molar pregnancyCarrying twins or more raises the risk of pregnancy sickness11; in a molar pregnancy, which cannot survive, the pregnancy hormone hCG is usually higher than normal and being sick often is a warning sign21The early pregnancy scan and hCG blood test in the diagnosis section
Weeks of vomiting that use up thiaminePregnancy raises the need for thiamine (vitamin B1), and in HG it can run out within weeks, which can lead to Wernicke's encephalopathy14Thiamine for anyone admitted with vomiting or severely reduced eating, given before any glucose drip15, as the supplement section sets out
DehydrationVomiting drains fluid, bringing thirst, tiredness, dizziness and little, dark urine; untreated HG can also lead to malnutrition1211Sipping fluids little and often, and IV fluids in the hospital when nothing will stay down12
Other conditions that cause vomitingA urinary tract infection can cause nausea and vomiting, and other conditions need ruling out before HG is diagnosed1112The urine test, thyroid tests and scan in the diagnosis section
Diagnosis

How Hyperemesis Gravidarum Is Diagnosed

HG is a clinical diagnosis based on history, examination and labs. Lab and ultrasound testing rule out other conditions and assess severity.

TestWhat it shows
At-Home Screening
These are not diagnostic, but track severity and signal when clinical care is needed urgently:
PUQE-⁠24 Score (Pregnancy-Unique Quantification of Emesis)Score yourself daily over 24 hours: (1) How long have you felt nauseated, 1 to 5 (not at all to more than 6 hours)? (2) How many times have you vomited, 1 to 5 (none to 7+)? (3) How many times have you had retching/dry heaves, 1 to 5 (none to 7+)?8 Total score: 3 to 6 mild, 7 to 12 moderate, 13 to 15 severe. Bring scores to every OB visit.
Weight & Hydration DiaryWeigh weekly (or daily if losing) on the same scale, same time, same clothing. Track every oz of fluid retained, vomiting episodes, urine output (number of voids and color) and any signs of dehydration.
Urine Ketone Strips MisleadKetones in urine do not measure dehydration or how severe HG is, so a strip cannot tell you whether you need care15; act on the signs in the warning box above instead.
Lab & Clinical Tests
Electrolyte & Renal PanelSodium, potassium, chloride, bicarbonate (look for hypokalemic, hypochloremic metabolic alkalosis), BUN (urea), creatinine (often raised because dehydration strains the kidneys), magnesium, phosphorus.
CBC & Liver Function TestsHematocrit often elevated from hemoconcentration. LFTs may be mildly raised in severe HG; later in pregnancy, rule out HELLP syndrome, a serious complication affecting the liver and blood. Lipase / amylase may be mildly raised; rule out pancreatitis.
Thyroid PanelTSH, free T4. HG is associated with transient gestational hyperthyroidism due to hCG cross-stimulation of TSH receptors; mostly self-resolving.
Pelvic UltrasoundConfirms viable intrauterine pregnancy. Rules out twin/triplet pregnancy and molar pregnancy, both of which can present with severe HG due to extremely high hCG.
Urinalysis & KetonesUrine dipstick for nitrites and leukocytes (UTI as a trigger); ketones in urine do not measure dehydration or severity15.
Wernicke's Risk AssessmentAny woman with HG requiring IV fluids or with greater than 3 weeks of poor oral intake must receive IV thiamine 100 mg before any IV glucose or dextrose-containing fluid. Failure to do so risks Wernicke's encephalopathy, a preventable catastrophe.
Treatment Comparison

Conventional and Holistic Treatment for Hyperemesis Gravidarum

HG is a medical condition that needs both pharmacologic and supportive care. Holistic strategies complement, but never replace, anti-nausea medication and IV fluids in moderate-to-severe HG.

๐ŸŒฟ HOLISTIC
๐Ÿ’Š CONVENTIONAL
๐ŸŒฟ

Holistic / Functional Approach

Adjunctive support that lowers symptom burden and corrects deficiencies, layered onto OB-prescribed treatment

Primary Treatment
Vitamin B6 and ginger for milder nausea, alongside prescribed anti-nausea medicines rather than instead of them5; protein-dense bites when tolerated; electrolyte hydration; cold/bland foods; environmental control of triggers
Duration
From symptom onset (often weeks 5 to 6) until resolution (usually 14 to 20 weeks, sometimes longer)
Effect on Underlying Disorder
May ease milder symptoms and help replace nutrients and fluids; does not treat HG on its own, which needs prescribed medicine and, often, IV fluids
Maternal-Fetal Outcome
Best when combined with anti-nausea medication; helps quality of life and recovery between meds

Full Holistic Approach Includes

  • Vitamin B6 (pyridoxine) 25 mg 3 to 4×/day; ACOG first-line, pregnancy-safe. Not in addition to a prescribed doxylamine and B6 tablet, which already contains B6 9
  • Ginger 250 mg capsules 4×/day, or fresh ginger tea/candies (the evidence is limited and inconsistent; check with your midwife or pharmacist before ginger supplements)16
  • Acupressure wristbands or acupressure at P6 (wrist); some women get meaningful relief
  • Cold, bland, low-odor foods: watermelon, cold pasta, plain boiled rice, cold yogurt
  • Sip electrolyte water (oral rehydration solution, or homemade), tiny sips every few minutes
  • Protein-dense small bites between meals (cheese cube, hard-boiled egg, plain yogurt) when tolerated
  • Smell control: partner cooks elsewhere, leave windows open, no scented products in the home
  • Rest, no shame in bed days; mental health support; HER Foundation peer support
โš ๏ธ Side effects: Minimal at recommended doses. Critical: Holistic strategies are adjuncts, not substitutes, for moderate-to-severe HG. Refusing prescription anti-nausea medicines or IV fluids when needed is harmful to mother and baby. The goal is symptom management plus prevention of complications.
Supplement Protocol

Evidence-Based Supplements for Hyperemesis Gravidarum

Check every supplement below with your midwife or doctor before taking it in pregnancy; each row notes what is known about its safety. Items flagged as contraindicated should not be used during pregnancy. Critically, IV thiamine must precede any IV glucose in women with HG.

Supplement What it is for Typical range Timing Notes & cautions
Vitamin B6 (Pyridoxine)First-line anti-nausea treatment per ACOG. Trials of B6 alone show mixed results17. Combined with doxylamine, it is a standard first prescription step4.25 mg, 3 to 4 times per dayAround the clock, do not wait for nauseaPregnancy-safe. The tolerable upper intake level is 100 mg/day for adults, including in pregnancy9, which 25 mg four times a day already reaches; go higher only under your prescriber's care. Often combined with doxylamine in a prescription tablet (10 mg of each in the US); if you take that tablet, do not add separate B6 on top.
Thiamine (Vitamin B1) โš ๏ธ CRITICALPrevents Wernicke's encephalopathy in HG. Must be given before any IV glucose. Orally helpful for prevention.50 to 100 mg/day orally; 100 mg IV before any IV dextroseDaily; IV form on hospital protocolPregnancy-safe and critical. Must precede IV glucose to prevent Wernicke's.
Ginger (Capsule or Whole)May help nausea and vomiting in early pregnancy, though the trial evidence is limited and inconsistent. Studied at 250 mg 4×/day.250 mg, 4 times per dayAround the clock, with or without foodGinger supplements may be safe in pregnancy; check with your midwife, doctor or pharmacist before taking them16. Avoid extremely high concentrated doses (greater than 1,500 mg/day).
High-Quality Prenatal MultivitaminFoundation when tolerated. Switch to liquid or chewable forms if pills are not tolerated. Skip iron temporarily if it worsens nausea.1 per day per productWith food at the best-tolerated timePregnancy-essential. If you can't tolerate it, take folate + B12 + iodine separately until prenatal is tolerated.
Folate (Folic Acid)Critical for fetal neural tube; if prenatal cannot be tolerated, ensure folate is taken separately.800 to 1,000 mcg/dayBest-tolerated timePregnancy-essential. Folic acid works for people with MTHFR gene variants too, and it is the only type of folate shown to help prevent neural tube defects10.
Vitamin B12 (sublingual)A sublingual form avoids swallowing a tablet. Supports energy, neurological function. Often depleted by repeated vomiting.500 to 1,000 mcg/day sublingualMorningPregnancy-safe. Sublingual avoids triggering nausea from swallowing.
Magnesium GlycinateOften depleted by vomiting; helps with cramps, sleep and sometimes nausea.200 to 400 mg elemental Mg/dayEvening before bedPregnancy-safe in glycinate form. Avoid magnesium oxide / citrate (laxative effect; may worsen vomiting). The top of this range is above the 350 mg/day upper intake level for supplemental magnesium; above that, diarrhea is common. With kidney disease, take it only on your clinician's advice.
Electrolyte Replacement (oral)Restores sodium, potassium, chloride lost to vomiting. Critical to prevent the dehydration spiral.1 to 2 packets/day of oral rehydration salts, or homemadeSip throughout the dayPregnancy-safe. Choose oral rehydration salts over sugary sports drinks. Homemade: about 4 cups (1 L) of water + 1/2 tsp salt + 6 tsp sugar (WHO ORS formula).
Vitamin D3 (with K2)Pregnancy support; often deficient. Take liquid/drop form if pills are not tolerated.2,000 to 4,000 IU D3 + 100 to 200 mcg MK-⁠7 K2/dayWith a fat-containing meal if possibleConfirm the dose with your obstetric provider; the Endocrine Society advises against routine vitamin D blood tests in pregnancy. ACOG notes that an optimal serum level in pregnancy has not been established, so there is no target level to aim at. 4,000 IU/day is the adult tolerable upper intake level and was well tolerated throughout pregnancy in a randomized trial; anything above that needs monitoring, and in pregnancy that means your obstetric team. If you take a blood thinner in pregnancy, tell the team managing it about any vitamin K supplement before starting or stopping it; vitamin K works against warfarin in particular, though warfarin is rarely used in pregnancy.
Iron (only if deficient, only if tolerated)Iron deficiency common after HG; oral iron worsens nausea in many women. IV iron is an option if oral is intolerable.30 to 60 mg elemental iron/day if toleratedEvening (less nausea); empty stomach with vitamin C if toleratedPregnancy-safe when indicated. If oral is intolerable, discuss IV iron with OB. The top of this range sits above the 45 mg/day tolerable upper intake level for adults. That is appropriate only when correcting a confirmed deficiency under clinical supervision, not as general supplementation. Test ferritin first, and retest rather than staying on it indefinitely.
High-Dose Vitamin A (Retinol) โŒPreformed retinol is teratogenic above 10,000 IU/day, and in pregnancy the practical limit is lower still, 5,000 IU/day. Avoid cod liver oil at higher doses and any "vitamin A" supplement during pregnancy.Avoid greater than 5,000 IU retinol/dayStick to beta-carotene + prenatal levelsPregnancy caution. Beta-carotene from food is safe; preformed vitamin A must be limited.
Herbal Anti-Nausea Blends (Misc.) โš ๏ธMany herbal blends contain ingredients (e.g., chamomile high-dose, raspberry leaf, black cohosh) that are not pregnancy-safe.Avoid unless every ingredient is pregnancy-clearedAvoid without provider reviewCheck every ingredient. Complex blends are not cleared for pregnancy; check even single-ingredient ginger with your midwife or pharmacist first.
โš ๏ธ Pregnancy + HG supplement principle: Confirm every supplement with your OB or midwife. If you cannot keep oral supplements down, IV/IM vitamin administration (B-complex, thiamine, B12) is reasonable; talk to your provider. Thiamine before glucose is a vital safety rule in HG care.
What to Expect

What to Expect Over Time

HG is treated with prescribed medicine and fluids, and food and supplements support recovery around them12.

Treatment and supportive care, together
First Weeks

Tell your midwife or doctor early. Vitamin B6 may be tried first, with an antihistamine added if needed22; anti-nausea medicines that are safe in pregnancy, including the first 12 weeks, come next12. Small plain meals and sips of fluid help alongside them11.

Months 1 to 3

If vomiting is not controlled, hospital care gives fluids through a drip and medicine by injection12; anyone admitted with vomiting should receive thiamine, especially before a glucose drip15.

Months 3 to 12

Some symptoms may ease around 20 weeks, but HG may last until the birth. Treated effectively, it is unlikely to harm the baby12.

Long Term

HG often returns in a later pregnancy; plan ahead and ask about starting medicine early12.

When to Seek Care

Call 911 or go to the emergency department (or call 999 in the UK) if you are vomiting and your skin, lips or tongue look blue, gray, pale or blotchy, your skin feels cold, you breathe fast or with difficulty, or you are unusually sleepy or hard to wake, which can mean shock13; or for confusion, double or blurred vision or unsteadiness, which can signal thiamine deficiency14; or if you vomit blood. Get urgent same-day help from your midwife or doctor (NHS 111 in the UK) if you cannot keep food or fluids down for 24 hours; have not peed for 8 hours or have very dark urine; feel very weak, dizzy or faint; have abdominal pain or a high temperature; or have lost weight11. Do not wait or try diet changes first.

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Next Steps

A Biological Condition, Highly Treatable

HG is a biological condition, not a psychological one, and it is treated with prescribed medicine and fluids. Tell your midwife or doctor early, and use small plain meals and sips of fluid alongside treatment. If you cannot keep food or fluids down for 24 hours, get same-day help.

Explore Thyroid Disorders โ†’ Explore Depression โ†’

References & Evidence Notes

Each numbered entry below is either a source you can follow or a note setting out what the evidence does and does not support. Both are numbered together so the markers in the text line up.

Last reviewed October 20, 2026. Supplement entries are cross-checked against the NIH National Center for Complementary and Integrative Health and the Linus Pauling Institute Micronutrient Information Center.7 Hyperemesis gravidarum is not ordinary morning sickness. It is a distinct condition, and it is treatable. Two things are genuinely urgent. If you cannot keep fluids down for more than about 24 hours, are passing little urine, have lost more than 5% of your pre-pregnancy weight or feel faint, you need assessment and probably intravenous fluids. And thiamine must be given before any glucose-containing fluid, because glucose without thiamine in a depleted person can precipitate Wernicke's encephalopathy, which causes permanent neurological damage. Confusion, unsteadiness or eye movement problems in someone with prolonged vomiting are an emergency. Anti-nausea medicines in pregnancy have been studied extensively; asking for them is not taking a risk with your baby.

  1. On what distinguishes HG: persistent vomiting with dehydration, electrolyte disturbance, ketosis and weight loss exceeding roughly 5% of pre-pregnancy weight, sufficient to impair function. Validated scoring such as PUQE helps separate it from ordinary nausea and vomiting of pregnancy, which affects most pregnancies and is self-limiting. ↩
  2. On the biology, which matters because women are so often disbelieved. Research has identified the hormone GDF15, produced by the placenta, as a major driver: a 2024 study reported that fetal production of GDF15 and maternal sensitivity to it both contribute substantially to risk, PubMed 38092039. This places HG firmly as a biological condition with a hormonal mechanism, not a psychological one, and it explains familial recurrence. ↩
  3. On thiamine and Wernicke's encephalopathy. Prolonged vomiting depletes thiamine within weeks. Administering glucose to a thiamine-depleted person accelerates consumption of remaining stores and can precipitate Wernicke's encephalopathy, which presents with confusion, ataxia and eye movement abnormalities and can cause lasting damage; hyperemesis gravidarum is among the classic nonalcoholic causes, PubMed 42621645. Thiamine is given before glucose-containing fluids, and this is a recognized and preventable complication of HG. ↩
  4. On treatment: a stepped approach from pyridoxine with or without doxylamine, through antihistamines and dopamine antagonists, to ondansetron and corticosteroids in refractory cases. Safety data in pregnancy are extensive for the older agents. Intravenous fluids, electrolyte correction and, rarely, enteral or parenteral nutrition are used where oral intake fails. Undertreatment is far more common than overtreatment. ↩
  5. On ginger and vitamin B6: both have randomized evidence for mild to moderate nausea and vomiting of pregnancy and are reasonable first steps there. Neither is adequate treatment for hyperemesis, and offering them as though they were is one of the most common ways women with HG are dismissed. ↩
  6. On refeeding: rapid reintroduction of nutrition after prolonged starvation risks refeeding syndrome, with falls in phosphate, potassium and magnesium. Reintroduction should be gradual with electrolyte monitoring in severe or prolonged cases, and thiamine given first. This is a hospital consideration and it is included because it explains why feeding is advanced slowly. ↩
  7. National Center for Complementary and Integrative Health (NIH), nccih.nih.gov, and the Linus Pauling Institute Micronutrient Information Center, lpi.oregonstate.edu/mic. ↩
  8. On the PUQE score: each of the three questions is scored 1 to 5, so the total runs from 3 to 15; 3 to 6 is mild, 7 to 12 moderate and 13 or more severe, as used in a Norwegian validation study in women with hyperemesis gravidarum, PubMed 25830549. ↩
  9. On vitamin B6 limits: the tolerable upper intake level is 100 mg/day for adults, including during pregnancy and lactation, and it does not apply to people taking B6 as a treatment under a physician's care, per the NIH Office of Dietary Supplements, ods.od.nih.gov. ↩
  10. On folate and MTHFR: people with an MTHFR gene variant can process all types of folate, including folic acid, and folic acid is the only type of folate shown to help prevent neural tube defects, per the US Centers for Disease Control and Prevention, cdc.gov. ↩
  11. On when to get help and what to try: NHS guidance advises calling a midwife, doctor or 111 if you are vomiting and have very dark urine or have not peed for more than 8 hours, cannot keep food or fluids down for 24 hours, feel very weak, dizzy or faint on standing, have belly pain or a high temperature, vomit blood or have lost weight. It lists carrying twins or more among the risk factors, notes that a urinary tract infection can also cause nausea and vomiting, and for milder sickness suggests rest, small frequent plain meals, cold foods, sipping fluids little and often and ginger foods or drinks, checking with a pharmacist before ginger supplements, with an anti-nausea medicine that is safe in pregnancy when these do not work, NHS, vomiting and morning sickness. ↩
  12. On hyperemesis gravidarum: NHS guidance states that it affects around 1 to 3 in every 100 pregnancies and often needs hospital treatment, that it may not get better by 16 to 20 weeks and may not clear completely until the baby is born, that it runs in families and is more likely after HG in a previous pregnancy, and that other causes of vomiting need ruling out first. Anti-nausea medicines, steroids or a combination can be used in pregnancy, including the first 12 weeks, with fluids through a drip and medicine by injection in the hospital if vomiting cannot be controlled. HG is unlikely to harm the baby if treated effectively, though weight loss raises the chance of a low birthweight, and anyone who has had it before is advised to plan ahead and talk to their doctor about starting medicine early, NHS, severe vomiting in pregnancy. ↩
  13. On shock from dehydration: NHS guidance advises calling emergency services or going to an emergency department for anyone with signs of dehydration who also has blue, gray, pale or blotchy skin, lips or tongue, cold skin, difficulty breathing or fast breathing, confusion, or is sleepier than normal or hard to wake, because these could be signs of shock, NHS, dehydration. ↩
  14. On thiamine deficiency: a systematic review of 177 reported cases of Wernicke's encephalopathy in hyperemesis gravidarum found that women had been vomiting for a median of 7 weeks and ran out of thiamine between 10 and 15 weeks of pregnancy, that double and blurred vision were common early signs, that glucose drips made it worse in some cases, and that lasting cognitive problems followed in about two-thirds; the authors advise 100 mg of thiamine by injection for anyone with persistent or severe vomiting, PubMed 30889425. ↩
  15. On the UK guideline: the Royal College of Obstetricians and Gynaecologists guideline (2024) states that first-line anti-nausea medicines have safety and efficacy data and should be prescribed when needed, that a second-line medicine should not be discouraged if they do not work and medicines can be combined, that ketones in urine are not an indicator of dehydration and should not be used to judge severity, and that thiamine (vitamin B1) should be given to everyone admitted with vomiting or severely reduced eating, especially before a glucose drip or tube feeding, PubMed 38311315. ↩
  16. On ginger: the NIH National Center for Complementary and Integrative Health says research shows ginger may help the nausea and vomiting of pregnancy and that ginger supplements may be safe in pregnancy, but advises consulting your health care provider before using them, NCCIH, ginger; a Cochrane review of 41 trials in early pregnancy found the evidence for ginger limited and not consistent, PubMed 26348534. ↩
  17. On vitamin B6: the NIH Office of Dietary Supplements reports mixed results for B6 alone in pregnancy sickness (two placebo-controlled trials of 30 to 75 mg a day reduced nausea, and a Cochrane review could not draw firm conclusions), notes that ACOG recommends 10 to 25 mg three or four times a day with an antihistamine added if needed, and advises pregnant women to consult a physician before taking B6 because doses can approach the upper limit of 100 mg a day, NIH Office of Dietary Supplements, vitamin B6. ↩
  18. On recurrence: in Finnish national registers for 2004 to 2011, HG recurred in 24% of the pregnancies that followed a first affected pregnancy (1,836 women, 2,267 later pregnancies), PubMed 30121224; a systematic review found five cohort studies reporting recurrence from 15 to 81%, too varied to pool, PubMed 32021976. ↩
  19. On family history: in a study comparing women treated with intravenous fluids for severe pregnancy sickness with unaffected friends, 33% of the women with HG reported an affected mother against 7.7% of the controls, and sisters of women with HG had a much higher risk themselves (odds ratio 17.3), PubMed 20974461. ↩
  20. On care and its consequences: in a UK-wide survey of 5,071 women with HG, 4.9% had ended a wanted pregnancy because of HG and a further 52.1% had considered it, and 41.2% of those taking prescribed medicine had to ask for it themselves; the authors call for timely access to medicine, mental health assessment and compassionate care, PubMed 36262812. ↩
  21. On molar pregnancy: NHS guidance explains that a molar pregnancy is a rare problem with a fertilized egg that means the pregnancy cannot survive, that the pregnancy hormone hCG is usually higher than normal, that it may be found on the first scan at around 8 to 14 weeks, and that vomiting often (severe morning sickness) is one reason to call a midwife or doctor urgently, NHS, molar pregnancy. ↩
  22. On first steps in the US: the American College of Obstetricians and Gynecologists states that vitamin B6 is a safe, over-the-counter treatment that may be tried first, that an antihistamine can be added if B6 alone does not help, that both have been found safe in pregnancy, and that people with hyperemesis gravidarum need treatment, sometimes in the hospital, with fluids and vitamins through a drip if they are dehydrated, ACOG, morning sickness. ↩