Last mensturatn cycle ws of 34 days n this 1 ws of 46 days. wot may b d reasons for such late cycles?. age-18 ; active in sexual activities.

Possible reasons: Reasons for missed/late periods: low body weight, obesity, marked weight ^ or v, over-exercise, endurance athletics, breast-feeding, ^ stress, illness, eating disorders (bulimia or anorexia), anovulatory cycle (no egg released), travel, hormone irregularities, drug use, meds (i.e., birth control) or medical problems (polycystic ovary syndrome or asherman’s syndrome). #1 reason is pregnancy.

See your doctor: Of course, if you are sexually active, every time your period is late, you might be pregnant. There are many other possible causes: greatly reduced body fat from extreme athletic training, starvation, polycsystic ovary disease, and other conditions. See your doctor, who might prescribe oral birth control pills to help regulate your cycles and prevent pregnancy (unless you are trying to conceive).