Severe vomiting during pregnancy can cause a dangerous vitamin B1 (thiamine) shortage that may damage the brain. According to research reviewed by Gram, a 2026 Cureus case report describing one 35-year-old woman who lost about 19 kg (42 pounds) showed full recovery after prompt IV thiamine treatment.
Severe vomiting during pregnancy can sometimes lead to a shortage of vitamin B1, also called thiamine, and that shortage can affect the brain. A new case report published in Cureus in 2026 describes a 35-year-old woman who lost about 19 kg (42 pounds) from prolonged vomiting and developed eye movement problems, dizziness, and unsteady walking at 15 weeks of pregnancy. Doctors diagnosed a condition called Wernicke’s encephalopathy and treated her with thiamine given through an IV, followed by thiamine pills and nutrition support. Her symptoms and brain scan changes fully resolved. According to research reviewed by Gram, the report highlights that this complication is easy to miss and that quick treatment matters. Because the findings come from a single patient, they show what can happen rather than how common it is. Anyone with long-lasting pregnancy vomiting and new neurological symptoms should contact a doctor promptly.
Key Statistics
A 2026 case report published in Cureus described a 35-year-old woman who lost about 19 kg (42 pounds) from severe pregnancy vomiting and was diagnosed with Wernicke’s encephalopathy at 15 weeks of pregnancy.
In the 2026 Cureus case report, the patient had three hospital admissions for severe vomiting, and her neurological symptoms fully resolved after intravenous thiamine treatment.
The 2026 Cureus case report involved a single patient, so it shows one possible outcome of vitamin B1 deficiency in pregnancy rather than how often the condition occurs.
The Quick Take
- What they studied: Can extreme pregnancy vomiting cause a vitamin B1 shortage that affects the brain, and how was one patient diagnosed and treated?
- Who participated: One woman, age 35, who had severe pregnancy vomiting and was admitted to the hospital three times. She lost about 19 kg (42 pounds) and was 15 weeks pregnant when symptoms of brain involvement appeared.
- Key finding: The woman had eye movement problems, drooping eyelid, dizziness, and unsteady walking, along with brain scan changes typical of vitamin B1 deficiency. After IV thiamine, followed by pills and diet support, she made a complete recovery. Because this is one patient, the result shows a possible outcome, not a measured rate.
- What it means for you: If you are pregnant and cannot keep food or fluids down for long periods, tell your doctor. Ask whether you need a thiamine check or treatment. New problems with vision, balance, or walking need urgent medical attention, even if you do not feel confused.
The Research Details
This was a case report, which means the authors carefully described the medical history, symptoms, test results, and treatment of one patient. It is a detailed story of a single case rather than a study that compares groups of people. The woman’s history included three hospital stays for severe vomiting and a large amount of weight loss before her neurological symptoms began.
At 15 weeks of pregnancy, after a missed miscarriage was diagnosed, she developed blurred vision, drooping of one eyelid, dizziness, and trouble walking steadily. Doctors examined her eye movements and found involuntary side-to-side eye jerking and reduced ability to move one eye outward. She was not confused. Brain MRI scans showed changes in areas that are known to be affected by vitamin B1 shortage.
The team treated her with a combination of IV Pabrinex, which contains thiamine along with other B vitamins, then oral thiamine and dietary support. The authors also noted some blood test patterns that suggested refeeding syndrome, a risk that can occur when nutrition is restarted after a long period without food.
A case report is useful for spotting conditions that doctors might not expect. It can alert other clinicians to warning signs they may otherwise miss. It cannot tell us how often this happens, whether treatment works for everyone, or what the best dose would be. Those questions require larger studies.
The report is detailed and includes clinical signs, imaging, and the treatment response, which makes the diagnosis and recovery easier to follow. Its main limitation is that it describes only one woman, so it cannot establish how common this complication is or prove that a specific treatment caused the recovery. Cureus is a peer-reviewed, openly accessible journal that publishes case reports, but case reports are generally considered early-level evidence.
What the Results Show
The main result is that the woman was diagnosed with Wernicke’s encephalopathy, a serious brain condition caused by a lack of thiamine, which is vitamin B1. Her symptoms, including eye movement problems and balance trouble, matched this diagnosis. Her brain scans also showed the expected changes in regions deep in the brain that depend on thiamine.
The authors reported that her symptoms did not include confusion, which is one of the classic three features of the condition. This is why the authors stress that doctors should consider the diagnosis even when not all the typical signs are present. Waiting for the full set of symptoms could delay treatment.
After receiving IV thiamine, the woman improved and then continued with oral thiamine and food-based nutrition support. The report states that her neurological symptoms fully resolved and her brain imaging returned to normal. The authors also noted that some lab findings suggested refeeding syndrome, which means the body’s electrolytes and minerals can shift dangerously when nutrition restarts after a long gap.
The report notes that the woman’s weight loss of about 19 kg (42 pounds) during pregnancy was a major sign of how severe her nutritional shortfall had become. Her three hospital admissions also show how long and disruptive the illness was. Together, these details suggest that repeated episodes of severe vomiting can signal a need for closer nutritional monitoring.
The case also points to the importance of coordinating care among different specialists. Obstetric, neurology, and nutrition teams were involved in her care. The authors suggest that early teamwork may help catch complications sooner.
Wernicke’s encephalopathy is well described in medical literature as a complication of severe vomiting, prolonged fasting, and malnutrition, including in pregnancy. This report fits with that established knowledge and adds a detailed, recent example in the second trimester. Its value lies in reminding clinicians that the condition is underrecognized in pregnant patients, not in offering new mechanisms or treatments.
The most important limitation is that the findings come from one patient. A single case cannot show how common this complication is, how often it is missed, or whether the treatment approach would work the same way for others. The authors did not compare different treatment options, and the report does not include long-term follow-up beyond the recovery period described. Individual medical histories, other health conditions, and the exact timing of care can all affect results, so the recovery in this case may not reflect what happens in every patient.
The Bottom Line
Research shows that thiamine deficiency can cause serious brain problems in people with prolonged vomiting, and this case supports prompt medical evaluation. Based on established medical understanding and this case, people with severe pregnancy vomiting and any new eye, balance, or walking problems should seek urgent care, and clinicians should consider thiamine treatment promptly. Confidence is high that thiamine deficiency is a real risk and that early IV treatment is standard practice for suspected Wernicke’s encephalopathy. Confidence is low about how common the problem is in pregnancy, because this report describes only one patient.
Pregnant people who are vomiting so much that they cannot keep food or fluids down, especially those who have lost significant weight, should care about this. Family members and caregivers who notice unusual eye movements, confusion, or unsteady walking should also pay attention. Healthcare professionals who treat pregnancy vomiting may find it useful. People who are not pregnant and do not have prolonged vomiting or malnutrition are less likely to be affected by this specific risk. Do not start high-dose vitamin supplements on your own without medical advice.
In the case described, symptoms improved after IV thiamine treatment, and the woman later recovered completely. Recovery times for Wernicke’s encephalopathy vary, and early treatment is generally linked with better outcomes. Some people may need weeks or months of care, and some may have lasting effects if treatment is delayed. Expectations should be set by the treating medical team, who can monitor progress.
Frequently Asked Questions
Can severe morning sickness cause brain damage during pregnancy?
Severe pregnancy vomiting can lead to a vitamin B1 (thiamine) deficiency, which may cause a serious brain condition called Wernicke’s encephalopathy. A 2026 Cureus case report described one woman who lost about 19 kg and recovered fully after prompt IV thiamine treatment.
What are the warning signs of thiamine deficiency from vomiting?
Warning signs can include blurred or double vision, drooping eyelids, involuntary eye movements, dizziness, and unsteady walking. Confusion is a common sign but may be absent. Anyone with prolonged vomiting who develops these symptoms should seek urgent medical care.
How is Wernicke’s encephalopathy treated during pregnancy?
Treatment usually starts with intravenous thiamine, often given alongside other B vitamins, followed by oral thiamine and nutrition support. In a 2026 case report, the patient fully recovered and her brain scan abnormalities resolved after this treatment approach.
Is it safe to take vitamin B1 for pregnancy vomiting?
Vitamin B1 should only be used under a doctor’s guidance, especially during pregnancy. Dosing depends on the cause and severity of the deficiency. Severe cases often need IV treatment, so anyone with persistent vomiting should speak with their healthcare provider before starting supplements.
Want to Apply This Research?
- Track daily episodes of vomiting, the number of meals or snacks you can keep down, and fluid intake in ounces or milliliters. Log your weight once or twice a week at the same time of day. Record any new vision changes, dizziness, or walking difficulty with a simple yes or no entry and the time it started.
- Use the app to set a daily goal of small, frequent sips of fluid and small meals that include a thiamine-rich food, such as whole grains, beans, or fortified cereals, if your doctor agrees. If you notice you are keeping less than a set amount down for two days in a row, the app should prompt you to contact your care team.
- Review your weekly weight, intake, and symptom logs with your healthcare provider at each prenatal visit. Set alerts for sudden weight drops or any new neurological symptoms so you can seek care quickly. Keep a shared record that you can bring to appointments or emergency visits, and update your plan as your provider adjusts your care.
This article summarizes a single case report and is for general education only. It is not medical advice and does not replace care from a qualified healthcare professional. If you are pregnant and experiencing persistent vomiting, weight loss, vision changes, dizziness, or trouble walking, seek medical care promptly. Do not start thiamine or other vitamin treatments without guidance from your doctor.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.