<br><div><img src="https://ichef.bbci.co.uk/news/1024/branded_news/7549/live/40cd9530-ace1-11f1-b1d1-571ed4d7ff2c.jpg" style="width: 100%" /><div>Menstrual cycles are highly individual, making blanket advice found on social media difficult to apply, researchers say.</div></div>