The largest study to date on pregnant women suffering from hyperemesis gravidarum (HG), a severe form of nausea and vomiting, has revealed a significant increase in the risk of neuropsychiatric and mental health disorders. Conducted by researchers from King’s College London and South London and Maudsley NHS Foundation Trust, the study examined 476,857 pregnant women diagnosed with HG across 135 healthcare providers worldwide.
This groundbreaking research utilized a retrospective cohort study approach, leveraging data from the TriNetX Global Collaborative Network, which collects anonymized electronic healthcare records from 18 countries. The findings indicate a more than 50% increased risk of developing 13 neuropsychiatric conditions, including post-partum psychosis and post-traumatic stress disorder (PTSD).
Understanding Hyperemesis Gravidarum
Hyperemesis gravidarum affects up to 3.6% of all pregnancies and is the leading cause of hospitalization during the first trimester. Unlike typical morning sickness, HG involves severe and persistent nausea and vomiting, often resulting in dehydration and weight loss. Many women with HG report feeling anxious, isolated, and uncertain about their ability to continue with the pregnancy. The condition has been linked to various mental health challenges, including anxiety and depression, with over half of affected women considering pregnancy termination.
Maternal risk factors for HG are diverse, ranging from biological issues such as thyroid and parathyroid disease and Type 1 diabetes to socioeconomic factors and ethnicity. Recent research has also suggested that sensitivity to the hormone GDF-15 may contribute to the disorder.
Key Findings and Expert Insights
The study examined 24 neuropsychiatric and mental health outcomes within a year of HG diagnosis. It found that women with HG are twice as likely to develop conditions such as Wernicke’s encephalopathy, a neurological disorder caused by vitamin B1 deficiency, and refeeding syndrome, which can occur when food is reintroduced too quickly to a malnourished individual. The risk of post-partum depression was found to be 2.7 times higher.
“Many pregnant women experience nausea and vomiting, but for women with HG, this occurs at a level far from ‘normal’ and can be profoundly debilitating,” said Dr. Hamilton Morrin, Doctoral Fellow at King’s College London. “Our study not only confirmed the increased risk of anxiety, depression, and PTSD but also highlighted severe mental health conditions like psychosis and eating disorders.”
Dr. Morrin emphasized the need for urgent referral to specialist services for women experiencing these conditions to ensure the safety of both mother and child.
Implications of the ICD-11 Classification
The World Health Organization’s latest International Classification of Diseases (ICD-11) categorizes HG into “mild HG” and “HG with metabolic disturbance.” The latter involves complications such as carbohydrate depletion, dehydration, or electrolyte imbalance. The study explored whether this classification correlates with mental health outcomes and found that cases of HG with metabolic disturbance showed a significantly reduced risk of depression compared to mild HG.
“The severity of HG does not directly correlate with the degree of impact on mental health,” Dr. Morrin noted. “As clinicians, we have a responsibility to ensure these women receive adequate integrated care across both physical and mental health.”
Bridging the Gap in Care
Dr. Thomas Pollak, Clinical Reader and Consultant Neuropsychiatrist at King’s College London, highlighted the disconnect between the medical community’s perception of HG’s mental health impact and the experiences reported by women. “Our findings show that this gap is not only real but can be very serious. HG can be associated with severe psychiatric disorders that require urgent recognition and joined-up physical and mental healthcare from the very start of pregnancy,” he said.
The study, titled “Neuropsychiatric and Mental Health Outcomes in Hyperemesis Gravidarum: A Retrospective Cohort Study,” was published in The Lancet Obstetrics, Gynaecology, & Women’s Health and funded by the National Institute for Health Research (NIHR).
Looking Ahead
The implications of this study are profound, underscoring the need for comprehensive healthcare approaches that integrate both physical and mental health support for pregnant women with HG. As research continues, healthcare providers are urged to consider these findings in their treatment protocols, ensuring that women receive the holistic care necessary to navigate the challenges of HG.
