(女性经期的)腹绞痛
pains in the lower stomach caused by a woman's period
  She took some medicine for her cramps.
 She had monthly cramps for a year or two before her periods started.
 I woke up with terrible cramps this morning.
 Millions of women suffer from painful cramps during their periods.
 The pain felt very much like period cramps.
 See also: cramp noun