Why it is important
Hyperemesis gravidarum (HG) is a severe form of nausea and vomiting in pregnancy (NVP), affecting 0.3–3.6% of pregnant women. The recent international consensus definition specifies that symptoms of nausea and vomiting (one of which is severe) should begin before 16 weeks' gestation. Affected women are often unable to eat or drink normally, and symptoms significantly limit daily activities. HG is associated with serious maternal physical illness, including venous thromboembolism, Wernicke’s encephalopathy, and potentially fatal arrhythmia. It can lead to women becoming bedbound and unable to work or care for children and is associated with depression and suicidal thoughts. After pregnancy, affected women face increased rates of post-traumatic stress disorder. HG also increases the risk of fetal growth restriction and preterm birth, and the children of HG pregnancies are more likely to experience adiposity, metabolic disorders, and neurocognitive issues later in life.
Summary of current research
Our current research focuses on the causes and complications of hyperemesis gravidarum (HG). In terms of the aetiology of HG, we are collecting DNA samples from women of mixed ethnicity from the UK. Current research has shown that there is a genomic component to the aetiology of HG. The loci principally implicated in genome-wide association studies are GDF15 and IGFBP7, and exon sequencing has also demonstrated rare, potentially pathogenic mutations in GDF15. At present, the genetic studies have primarily used samples from European populations. We aim to delineate the genetic factors that make women susceptible to HG in mixed-ethnicity populations.
Melanie Nana holds an NIHR Fellowship to study nutrient deficiency in HG and its impact on maternal and child health. We are also investigating the effects of HG on maternal mental health and conducting a service evaluation of care provision for women with HG in Great Britain.
How the research benefits patients
Previous research found:
- 6.7% of women with hyperemesis gravidarum (HG) have regular suicidal thoughts.
- 5% of women terminate a wanted pregnancy, often due to perceived substandard management in primary or secondary care.
- Surveyed GPs and GP trainees on HG management:
Results showed a lack of confidence in managing HG.
- Participants expressed a desire for more education on the subject.
- Received funding for a Policy Lab in collaboration with the King’s Policy Institute, aimed at addressing gaps:
- Although HG guidelines exist, many women do not receive appropriate treatment.
Policy Lab outputs have impacted policy and education:
- Meetings enabled the inclusion of HG in the Women's Health Strategy.
- A Wellbeing of Women education webinar was conducted.
- Flowchart guidance endorsed by all relevant Royal Colleges was included in the latest national guidelines.
Researchers
- Pete Dixon
- Melanie Nana
- Anna Yang