Laser hair removal during menstruation is theoretically not harmful, but some factors should be taken into consideration:

Difficulties of Laser Hair Removal During Menstruation:
Pain Threshold May Change: Menstruation is a period when hormones change and the body is more sensitive. During this period, the pain threshold may decrease, so pain or discomfort may increase during laser hair removal. However, this varies from person to person and most people can have laser hair removal during their menstruation.

Skin Sensitivity: The skin may be more sensitive during menstruation. There is a possibility that it will react more to laser light, which may increase side effects such as redness, sensitivity or irritation. Therefore, it is useful to share this situation with your specialist to avoid any skin problems.

However:
There is no direct negative effect on the efficiency and safety of laser hair removal during menstruation. However, the hair growth cycle may differ slightly due to hormonal changes. This may affect the efficiency of the procedure, but this effect is usually temporary.

In Conclusion: It is generally safe to have laser hair removal during your period, but since the pain threshold and skin sensitivity may increase, it would be beneficial to inform your specialist about your condition before the procedure in order to increase your comfort. If you want a more comfortable experience, a time period outside of your period may be preferred.