My Wife Period Strategy On 11.30 P.m. On 1st December

My wife period strategy on 11.30 p.m. On 1st December then took overall l on 5th day of December at night but till now her next period is not starting . We are afraid of as with it her waist pain , left leg pain under knee is occurring . Then what she has to do ? That by getting your answer sir we can solve the problem .