Why is my menstrual flow limited?

A late period accompanied by light brown discharge with small blood clots is usually the result of hormonal disbalance, stress or pregnancy. I suggest that you see a gynecologist for an examination and appropriate diagnosis. The gynecologist is the best specialist to consult for any problem relating to menstrual health.
 

If you are observing a shorter than usual menstrual period, it could be that the cause is stress, hormone imbalance or a certain drug. It is advisable to visit a physician who specializes in women's reproductive health in order to diagnose the problem and to receive proper treatment.
 

menstrual cycles do vary slightly from month to month & changes in the timing or length of periods is due to stress, hormonal imbalances, or other health conditions. There is nothing to worry about, but if you experience persistent changes in your menstrual cycle consistently early or irregular periods it's better to talk to a gynec.

There can be factors contributing to changes in vaginal pH balance and the occurrence of vaginal infections. Sexual activity, particularly with a new partner, can sometimes disrupt the natural balance of bacteria in the vagina, leading to infections like bacterial vaginosis (BV) or yeast infections. This can happen due to the introduction of new bacteria or an alteration in the vaginal environment.

Masturbation does not cause pregnancy. Check with your gynec for your periods.