Basically, hormonal fluctuations during monthly cycle are the main cause for the mood swings in a girl especially before menstruation. Everyone involved are deeply affected due to this. But you can work it out with a right approach. Following are some ways to deal with the whole situation:

1. Note down the date you assume she will be premenstrual. You can mark the dates on calendar as well or save it in your phone. This would really help you in dealing with the whole situation. Knowing that she is on her pms period, it will help you to be calm and patient with her.

2. When she will be calm and in a good mood, you can share with her that you have read about pms and how it could be difficult for her and tell her that you will be supportive during her pms period. She will be touched by the whole idea. It is good to understand her problems because it is not something that she can control, it is completely biological.

3. If you think she is on her pms so she must be a bit moody, don’t drop any surprises to her as it could be dangerous on your part. Just wait for the right time to come when she is in a better frame of mind and can give complete attention to your news.

4. Don’t get yourself indulge in any tricky type of questions like “ do i look fat?” or “ do you like her outfit?” she seems to be very calm while asking those questions but your answers can play a vital role in changing her mood. So be smart while answering those tricky ones.