Day 1- 5: Menstruation phase

The uterine lining breaks down as menstruation begins and is discharged together with blood, unfertilised ovum and mucus

Day 6- 11: Repair phase

Uterine lining starts to rebuild and thicken.

Blood vessels in uterine lining are formed and ready to receive the implantation of fertilised ovum.

Day 12 - 17: Fertile phase

An ovum is released from the ovary on the 14th day of the menstrual cycle (ovulation). The uterine lining continues to thicken.

Fertilisation is likely to occur if sperms are present

Day 18 - 28: Premenstrual phase

The uterine lining continues to thicken and becomes richly supplied with blood vessels. 
Implantation of an embryo is ready if fertilisation occurs.

The menstrual cycle will repeat if fertilisation does not occur