Another study, conducted by the Hyperbaric Medicine Department at Virginia Mason Medical Center, found that hyperbaric chamber attendants who were menstruating showed a sevenfold higher risk of DCS than male attendants and nonmenstruating female attendants. Again, there is no research to show that this risk applies to divers, though much research remains to be done on this subject. The reason that women may be more susceptible to DCS during or close to their periods is not known, but it may be related to the bloating many women experience with the onset of their menstrual cycle. This bloating, or edema, is caused by fluid moving from the blood vessels of the body into the body's tissues, resulting in less volume in the bloodstream. Diuretics are drugs that help the body eliminate water and relieve the feeling of bloating.
Some women complain that they have difficulty equalizing their ears and sinuses when menstruating.
Edema may also be responsible for this. The fluid that moves into the tissues from the blood vessels causes puffiness, much in the way that putting a sponge into water makes it swell. If this swelling affects the lining of the sinuses and Eustachian tube, it can make equalizing these spaces more difficult. This issue requires good judgment on the diver's part. Many women report feeling increasingly anxious around the time of their period.