Chinese teenager Zheng Qinwen suffered with menstrual cramps as she lost to Poland’s Iga Swiatek in the French Open fourth round on Monday after taking a set off the world’s number one tennis player.Chinese teenager Zheng Qinwen suffered with menstrual cramps as she lost to Poland’s Iga Swiatek in the French Open fourth round on Monday after taking a set off the world’s number one tennis player.