Researchers led by the University of Warwick said the term "NVP" (Nausea and Vomiting in Pregnancy) is more appropriate because it reflects the fact that these symptoms can occur throughout the day.
In a study published in the British Journal of General Practice, they've called for medical professionals to start using "NVP" instead of "morning sickness", pointing out that these symptoms should not be ignored or dismissed if they don't take place soon after waking up.
After analysing "symptom diaries" maintained by 256 pregnant women, the researchers found that while vomiting is most likely to occur between 7am and 1pm, feelings of nausea and sickness can occur throughout the day.
Many pregnant women also experience vomiting well into the afternoon, researchers found. Overall, 94% of participants in the study said they experienced either nausea or vomiting, while 58% said they experienced both.
Professor Roger Gadsby of Warwick Medical School said in response to the findings: “Morning sickness is widely used by the general public, media and even healthcare professionals but it doesn’t give an accurate description of the condition.
“If a pregnant woman experiences sickness in the afternoon she may feel that this is unusual and wrong, or if she experiences no vomiting but feels nauseated all day she might think she is not covered by the term ‘morning sickness’. And those women who experience severe symptoms feel it trivialises the condition."
Professor Gadsby also pointed out that NVP can have a "significant negative impact on the lives of sufferers", which is why it should never be trivialised.
"It can cause feelings of depression, of being unable to look after the family, and of loss of time from paid work," he added. "Very severe NVP called hyperemesis gravidarm (HG) is the commonest cause of admission to hospital in the first trimester of pregnancy."