What are the risks of decompression sickness if a woman dives while she is menstruating?

In theory, the hormonal changes of the menstrual cycle can result in fluid retention and swelling of the tissues which could possibly affect gas exchange. There is very limited research in this area; however there are audits that have found that many of women with DCS were found to be at the early stages of their menstrual cycle. Another study has linked this to taking oral contraceptives which are known to increase blood viscosity and raise blood pressure. Therefore, women are urged to dive more conservatively around the time of their menstrual cycle particularly if they are taking oral contraceptives.