About 52 percent of women employees have experienced pain during their periods that has affected their work, a YouGov survey of 1,000 women for BBC Radio found, while 90 percent of women experienced some pain due to their time of the month.
A third of women had taken at least one sick day because of those pains. But only 27 percent told their employers they were suffering from pains related to their periods.
A YouGov survey of 1,000 women carried out for BBC Radio 5 Live found 52% had found it difficult to work because of the pain, while almost a third had taken time off work. Despite this, only 27% of women had told their bosses period pain was responsible.
"Menstruation is normal, but some women suffer terribly and they suffer in silence," Grudzinskas told the BBC. "I don't think women should be shy about it, and companies should be accommodating with leave for women who are struggling with painful periods."
Period pains affect each woman differently. Many experience abdominal cramps that vary in pain intensity, ranging from a dull pain to intense spasms. Other possible symptoms include diarrhea, nausea and headaches. Some period pain can be indicative of underlying health problems.
"There is also a lack of awareness about when painful periods mean that something is going wrong, like endometriosis," Grudzinskas said. "People forget that women make up half the workforce. If they feel supported, it will be a happy and productive workforce."