Update on diagnosis and management of hyperemesis gravidarum

While Canadian physicians wait for updated guidelines on hyperemesis gravidarum, a new review published in CMAJ provides current information on the management of the condition.The most recent Society of Obstetricians and Gynecologists of Canada (SOGC) guidelines for vomiting and nausea in pregnancy are from 2016, but Dr. Kirsten Duckitt, an obstetrician practicing in Vancouver Island, and colleagues are in the process of updating them. The Royal College of Obstetrics and Gynecologists in the U.K. also published new guidelines in February in the British Journal of Obstetrics and Gynecology.While the authors of the CMAJ review are experts from the Netherlands and the U.K., the information in the paper is “all very relevant” to Canadian practice, Dr. Duckitt said. The paper, by Dr. Larissa Jansen from the Amsterdam Reproduction and Development Research Institute and colleagues provide an update on the causes, diagnosis and treatment of hyperemesis gravidarum. The review doesn’t specifically address nausea.Updates include new diagnostic criteria. The authors stress that the presence of ketounuria is no longer needed to diagnose hyperemesis gravidarum and doesn’t provide an indication of its severity or need for treatment. Instead, the diagnosis is based on the presence of nausea and vomiting, the inability to eat and drink normally and if it’s seriously affecting activities of daily living. It can be diagnosed in the first 16 weeks of pregnancy. “It’s not based on a blood test or weight loss or anything like that, it’s really a practical definition,” Dr. Duckitt said.Patients and family physicians can sometimes be reluctant to prescribe and take medications due to concerns about harm to the fetus. But the medications are “old, well-known drugs that we have lots of experience with,” Dr. Duckitt noted. “They do work, but people have to prescribe them and people have to take them.” Read: Topiramate use during pregnancy has minimal effect on autism risk in childrenTreatment usually starts with one antiemetic medication. An antihistamine can be added for anticholinergic effect for those with too much saliva. The authors provide a table of various pharmacological treatments (e.g., doxylamine-pyridoxine, cyclizine, promethazine and dimenhydrinate) and their doses. If this fails, physicians could prescribe metoclopramide or ondansetron, although there remains insufficient evidence to determine if ondansetron is associated with increased risk of cleft palate and heart defects.Currently, the goal of treatments is to reduce symptom severity. Research is not yet clear on whether treatment improves offspring outcomes.Cannabis use is not advised, Dr. Jensen and colleagues conclude. “There’s this huge lay perception that cannabis is good for nausea and vomiting. But there’s no evidence that it’s effective and also, it’s bad in pregnancy,” Dr. Duckitt said. The SOGC has other guidelines about cannabis use along a woman’s lifespan. If the patient is dehydrated, physicians should prioritize getting them treatment in the community. “A lot of the time this can be treated in ambulatory care or people can be given fluids in the maternity ward. They don’t necessarily need to be admitted as inpatients,” Dr. Duckitt said.Physicians should investigate if there’s an electrolyte imbalance and if necessary, prescribe intravenous fluids, which include thiamine supplementation. If a patient is dehydrated with electrolyte imbalances, they may need to be admitted, Dr. Jensen and colleagues note.Physicians may consider referring the patient to a dietician and psychosocial support, the authors write. Read: Teen pregnancy raises risk of death in early adulthood, Ontario study suggestsThe CMAJ update includes a nod to recent research findings that open up the potential to better understand of the causes of vomiting and nausea in pregnancy and future pharmacological treatments, Dr. Duckitt noted. It refers to a recent finding published in Nature that identified a possible genetic basis for nausea and vomiting in pregnancy. Previous studies suggested that the severity of nausea and vomiting in pregnancy is related a person’s sensitivity to a hormone called growth differentiation factor 15 (GDF15). The new Nature paper suggests that GDF15 levels in the parents’ bloodstream are higher on average for those who experience nausea, vomiting and hyperemesis gravidarum than those who do not. Those who initially have low circulating GDF15 before becoming pregnant could be more sensitive to the increase in GDF15 from the fetus during pregnancy. The researchers also identified a genetic variant which may explain the different levels of GDF15 in pregnant people. Other research has focused on the presence of Heliobacter pylori and also the role of human chorionic gonadotropin (hCG) as possible factors contributing to hyperemesis gravidarum.The CMAJ paper was published on April 15.The 2016 SOGC guidelines on the management of nausea and vomiting of pregnancy was published in the Journal of Obstetrics and Gynecology of Canada.The 2024 Royal College of Obstetrics and Gynecologists guidelines on the management of nausea and vomiting of pregnancy and hyperemesis gravidarum was published in the British Journal of Obstetrics and Gynecology.The paper on GD15 was published in Nature in December 2023.Read: Bringing birth back to Indigenous communities

Update on diagnosis and management of hyperemesis gravidarum

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