Ovulation is the process and usually happens once in every menstrual cycle and causes the release of the mature egg from the ovary (about 14 days before menstruation). The released egg will enter the fallopian tube and made available for the fertilization. During ovulation, the body releases an increased amount of hormones like estrogen, luteinising hormone (LH) which causes thickening of uterine walls and prepares the uterus for pregnancy. It is also called as the most fertile period in the woman because chances of getting pregnant are increased.