A study at the University of Turku on pregnancy has found a link between severe morning sickness and depression.

Women who suffered severe morning sickness while pregnant were more likely to suffer from depression before and after their pregnancies, the research found. They were also diagnosed with post-partum depression earlier, according to a university release.

Severe morning sickness involves serious nausea and vomiting that prevents normal eating and drinking, making it difficult to cope with everyday life.

The condition affects up to 3.6 percent of pregnancies and is the most common cause of hospitalisation during the first trimester, the university explained.

Severe morning sickness can also cause significant psychosocial burdens to affected women. However, little is known about the condition's link to psychiatric conditions, the release noted.

The study's findings were based on examining medical data on more than 437,000 women from registries spanning the years 2004-2015.

The research found that 8.8 percent of women with severe morning sickness had suffered from depression before their pregnancies — the proportion was 1.0 percent in the comparison group.

The study suggested that severe morning sickness and depression may share common biological factors, the university said.

It noted that the findings underscore the importance of mental health assessments and monitoring of expecting mothers, and a need for a multidisciplinary model of treatment.

"Our study highlights that severe morning sickness is not just a physically burdensome condition, but also a significant mental health risk factor. The results support the need for closer cooperation between different specialties, such as psychiatry, gynaecology and general medicine," doctoral researcher Eeva Terävä-Utti said in the release.