Hi there.. Delayed periods could be because of many causes like Significant weight gain or loss,Overexercise,Poor nutrition, anemia, hypothyroidism, Smoking,Eating disorders like anorexia nervosa,Increased stress, Polycystic ovarian syndrome. Delayed periods wit less flow is commonly because of anemia(less hemoglobin)I suggest you get her hemoglobin and
tsh test done once. Tel to Have more iron rich foods like green leafy vegetables, pistachios, dates..
even if you have used protection(condom) yet there are chances she could become
pregnant as failure rates are high with condom usage.. she can take urine
pregnancy test after 40days of last period.. if its negative then good.. if it comes positive consult gynecologist soon for medical abortion ie by abortion pills..