Women and Diving Part 2 – The Menstrual Cycle & the Contraceptive “Pill” By Dr. Lynn Taylor the loss is insignificant. The next three articles will discuss With the use of tampons, possible concerns for female divers, there is no external blood starting here with discussing the loss anyway. Also, it is known that potential ‘risks’ associated with the many shark species are not attracted Whilst there is no different phases of the menstrual to the blood and other debris found strong scientific evidence, that cycle and taking the contraceptive in menstrual flow and Dr Carl women are more susceptible to pill. Future articles will review diving Edmonds has even speculated that decompression illness or dive during pregnancy and the this may be due to a repellent effect injuries/accidents during this time, controversial question of gender and of some component in menstrual research has shown that accidents in the risk of decompression illness. blood. In reality, the chance of being general are more common among attacked during your menstrual women during PMS. Sensible advice One obvious difference between period is probably far less than from would appear to be - if you are female and male divers – the activities such as spear-fishing. There notably affected by these symptoms, menstrual cycle: are few reported shark attacks on take extra care in diving and dive women, and there are no data to more conservatively than you would As much as women may want to be support the belief that menstruating do normally. seen as equal to men, there are some females are at an increased risk for inevitable physiological differences shark attacks. I have heard that I am more which can influence their diving and likely to get Decompression the majority of this series of articles Before my ‘period’ I suffer from Illness (DCI) at certain times of focus on some of the issues which Pre-Menstrual Syndrome (PMS) the menstrual cycle – is that true? specifically affect women divers. does this affect my diving? This article aims to provide answers The hormonal changes over the cycle to the most commonly asked Interestingly, one large survey of over can result in fluid retention and tissue questions relating to the menstrual a thousand women divers has swelling. Theoretically, this could cycle and the contraceptive “pill”. revealed that 7% of women chose affect tissue gas exchange behavior, to refrain from diving whilst they effectively making it a ‘slower’ tissue; Are women at an increased risk were menstruating and 12% said however, this theory is not proven in of shark attacks during they dived more conservatively. In practice. menstruation? this survey a high proportion of women almost three-quarters, Early research on this topic looked This is a question which diving reported that they do sometimes get at the relationship between the instructors are frequently asked by PMS symptoms. Their self- incidence of altitude chamber female divers, or their concerned perception was that they feel more decompression sickness in female partners, and it is one of the most tired, felt colder, had impaired chamber attendants at the US Air frequently asked questions on the reaction times, experienced more Force School of Aerospace Medicine Divers Alert Network website. In anxiety, felt more susceptible to and phase of the menstrual cycle). reality, the average blood lost during nitrogen narcosis and felt less in The researchers concluded “Women menstruation is so small amounting control. are at higher risk of developing to just a few mls per dive (50-150 altitude related DCI during mls occurring over several days) that menstruation, with the risk

11 decreasing linearly as the time since What could the possible mechanism *Diving ‘more conservatively’ could last menstrual period (LMP) be? Oral contraceptives have been involve making fewer dives, shorter increases”. The study was limited associated with an increase in blood and shallower dives and making by not being able to look at other pressure and an increased risk of longer safety stops. factors such as the influence of the thromboembolic disorders oral contraceptives. Interesting (development of clot-like vein For further information on medical findings but clearly, care must also occlusions, which can lead to an issues in diving, visit the DAN SEAP be taken regarding the relevance of emboli), especially in women over 35 website (www.danseap.org) or the extrapolating these observations in years. However, unless oral DAN America website altitude chamber attendants, to contraceptives pose a clinical (www.diversalertnetwork.org). If you divers in the underwater problem for individual women, there have specific concerns, I advise you environment. is still no strong data to suggest that to consult with a doctor who has had their use during recreational scuba specialist training in diving and As far as data in women divers are diving is a contraindication. hyperbaric medicine. A list of concerned, a group of researchers doctors who have diving medicine based in Plymouth, UK, coordinated SUMMARY qualifications from the South Pacific the completion of a questionnaire by Underwater Medicine Society can be women who were treated with • There is no evidence that women found on the SPUMS website hyperbaric therapy for symptoms of are more prone to shark attacks (www.spums.org.au). DCI. Twenty-three hyperbaric whilst menstruating. treatment centres worldwide • It may be prudent for women to ABOUT THE AUTHOR participated in the study, including dive ‘more conservatively’ and two in Australia and one in New carefully if they suffer from Pre Zealand. They also concluded “the Menstrual Syndrome. Lynn Taylor PhD, is a very keen incidence of DCI in women is • The limited data we have so far technical diver and prolific writer. influenced by the phase of the suggests it may be advisable for She is a DAN Oxygen Instructor, menstrual cycle. Incidence is greatest menstruating women to consider PADI dive instructor, cooordinator during the early phase of the cycle diving ‘more conservatively’* of DAN SEAP-NZ, and Dive [ie: menstruation] and lowest around during menstruation, particularly if Incident & Accident Recorder for the 3rd week of the cycle”. they are taking oral contraceptives. NZUA. What effect does the oral contraceptive “pill” have on the risk of DCI ? One recent retrospective review of women divers (956 divers) with DCI found 38 percent were menstruating at the time of their injury. Additionally, 85 percent of those taking oral contraceptives were menstruating at the time of the accident. This suggests, but does not prove, that women taking oral contraceptives are at increased risk of decompression illness during menstruation.

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Alert Diver, SEAP 12