Hollywood has a lot to answer for!
For the girls
I get asked this question quite often by girls who are worried about diving while menstruating. The short answer, which should make you breathe a sigh of relief, is no – regardless of what feminine hygiene products you prefer to use. (While we’re on the subject – forgive me boys – but tampons are perfectly safe to use while scuba diving and nothing strange or frightening happens to them inside your body on a dive. If you’re really worried, and there’s no reason to be, use a Mooncup – get one at Wellness Warehouse.)
DAN has a useful answer to this question on their international website. The research that has been done indicates that menstruating women are at no greater risk of shark attacks than men, or women who aren’t on their period.
What you should be aware of is that if you’re a woman, you’re more susceptible to dehydration during your period, which in turn increases the risk of decompression sickness. There is also research that indicates that the use of oral contraceptives may marginally increase a woman’s risk of DCS. So be sure to stay hydrated, do your safety stops, dive conservatively – and enjoy your diving!
For the boys (and the girls who are still reading)
Sharks are not interested in human (mammal) blood – they prefer fish! And what’s more, unless you’ve experienced massive trauma (in which case I doubt scuba diving will be the first thing on your mind), only miniscule quantities of blood will be leaking out into the water – whether it’s because you’ve got a cut or scratch on your body, or (if you’re a girl) you’re menstruating.
(To clarify, in case you’re puzzled: I took these photos of the signs on the restroom doors at the Southern Sun Grayston hotel in Johannesburg with my dodgy cellphone camera while I was there for a conference in June. I’ve been itching to use them since, and frankly didn’t have time to organise a photo shoot of a woman in white trousers frolicking alone on a beach!)