Hyperemesis gravidarum is associated with severe nausea and vomiting during pregnancy, preventing a person from eating and drinking normally, and making everyday life extremely difficult. It occurs in 0.3 to 3.6 percent of all pregnancies and is the most common cause of hospitalisation in the first trimester of pregnancy. In addition to the physical effects, severe nausea in pregnancy carries a considerable psychosocial burden. However, information on its association with psychiatric illness has been limited so far.

Researchers analysed register data from over 437,000 Finnish women from 2004 to 2017. The results show that 8.8 percent of women with severe nausea during pregnancy had depression before pregnancy, compared to 1.0 percent in the control group. This means that these women were more than five times as likely to experience depression before pregnancy.

In addition, they were also about 3.5 times more likely to develop new, previously undiagnosed depression after childbirth: 4.9 percent were diagnosed with a new-onset depression after childbirth, compared to 1.0 percent in the control group.

After giving birth, depression was also diagnosed earlier in women who had suffered from severe nausea during pregnancy compared to others. On average, depression was diagnosed 3.3 years after delivery in women with severe nausea during pregnancy, compared with an average of 4.5 years after delivery in their controls.

The study suggests that severe nausea during pregnancy and depression may have shared biological mechanisms. The findings highlight the importance of systematic psychiatric screening during and after pregnancy, and the need for a multidisciplinary approach to care.

‘Our research shows that severe nausea in pregnancy is not only a physically stressful condition, but also a significant mental health risk factor. The results emphasise the need for improved collaboration between psychiatry, gynaecology, and primary care. Our aim is also to raise awareness and improve access to support for these patients,’ says Dr Eeva Terävä-Utti from the University of Turku.

Although nausea and vomiting are common in pregnancy, affecting as many as 70% of pregnancies, severe vomiting and nausea can prevent people from eating and drinking sufficiently, leading to weight loss and dehydration.

“[Hyperemesis gravidarum] can have detrimental effects on maternal quality of life and may lead to short- and long-term adverse outcomes among offspring,” writes Dr. Larissa Jansen, Amsterdam Reproduction and Development Research Institute, Erasmus MC, Rotterdam, the Netherlands, with coauthors. “Management of hyperemesis gravidarum requires considerable health care resources, as it is a common reason for hospital admission and emergency department visits in the first trimester.”

The cause of hyperemesis gravidarum is not completely understood, but risk factors include pregnancy at a young age, female fetus, multiple or molar pregnancy, underlying medical conditions, and history of the condition during previous pregnancies.

Treatment is aimed at relieving symptoms and includes starting an antiemetic (anti-nausea) drug and other medications if the antiemetic is not effective. Remedies such as ginger products may alleviate mild nausea and vomiting for some people, but the evidence on its effectiveness in people with hyperemesis gravidarum is uncertain.

The authors caution against using cannabis for hyperemesis gravidarum.

“Use of cannabis in pregnancy has been associated with adverse neurocognitive outcomes in offspring, as well as other adverse pregnancy outcomes. Therefore, we advise against the use of cannabis in pregnancy.”

The authors note that there are many unanswered questions about how to prevent and manage hyperemesis gravidarum and that more research is needed.