Tennis legend Martina Navratilova has come out in support of Britain's Heather Watson, who said that "girl things" affected her during her Australian Open first-round defeat to Tsvetana Pironkova.
Media speculation around the effects of periods on women during sport has been intense, and Navratilova has said that it is a very real issue for all female athletes.
She told BBC Sport: "It sounds like an excuse but for women it is a reality. For me, I didn't even like to drive before I got my period, that's how out of it I was. So it certainly affected me on the tennis court. There were a few matches that I wish would have been played about three days earlier or three days later.
"It does affect women differently but it certainly doesn't help you. I think you can see that on the golf course. One day they shoot a 68, the next day they should a 78 and you think 'Must have gotten her period' because it really does play such a big role and it can happen at unexpected times.
"You may not even know it's coming. You're dreading it."
Watson succumbed to a 6-4 6-0 defeat.
