not bat an eyelid

イギリス人プロテニスプレーヤーのヘザー・ワトソン選手は若干22歳。先日行われた全豪オープンでは１回戦敗退に終わり，その敗因がmenstruation（having a/sb's period）であったことを公言し話題となっています。

batには「〈まぶたまつ毛〉をまたたかせる」という意味があり，not bat an eyelidで「｟くだけて｠平然としている, びくともしない」とありました（『プログレッシブ英和中辞典』小学館）。ここでは「最近ではみなが気にもとめない」と解釈できます。（Koyamamoto）

'Did you lose because you had your period?'
(CNN)How much information is too much information? When British tennis player Heather Watson said in a post-match interview that she lost her Australian Open round due to "girl things," she sparked a debate about menstruation that quickly spread across the world.
"Has sport's last taboo been broken?" wondered commentators, after the 22-year-old described feeling "light-headed" and "low on energy," putting it down to her period.
"We talk about sex quite openly, we talk about breast enlargements, we talk about so many things that people don't even bat an eyelid about these days," former British number one tennis player, Annabel Croft, told CNN.
http://edition.cnn.com/2015/02/06/sport/heather-watson-tennis-sport-women-menstruation-period/index.html