The hormones released before and during your period can certainly affect your bowel habits. Staying regular is an important part of being healthy and feeling comfortable. Drinking lots of water, exercising everyday and eating fibre-rich food such as wholegrain bread, fruit, veg and wholegrain cereals are all important to keep things moving through the body. You may need to talk with your pharmacist to get something to push start this process. If you are concerned, see your GP.