A study by a Swedish researcher on the effects of the menstrual cycle on sportswomen has suggested that injuries are more likely to occur when they have their period. The researcher Inger Jacobson connects the incidence of injuries to cyclic hormonal fluctuations causing the levels of relaxin (a hormone which relaxes ligaments) to rise during menstruation.
319 sportswomen were studied for the research and it was seen that women who were not on birth control pills were far more likely to have injuries ( mostly on their legs) when they had their period though both groups had the same rates of injury.
Other published studies have reported that women have less coordination, postural control and, reaction time during their period and so their judgement of joint positions is affected. It is also thought that since levels of oestrogen fall during menstruation, pain perception is increased and more injuries are reported during these times.
The director of the Lucozade Sport Science Academy, John Brewer, explained that the present perception was that non mensruating women had more injuries due to a lower bone density. The current findings, he felt, could be attributed to the effects of relaxin.
The FA women's team doctor, Dr Pippa Bennett, said that this factor has been considered and the players' injuries were being monitored closely. However she was uncertain whether women could definitely consider themselves at higher risk during menstruation, though performance could be affected slightly.