Pregnancy

Female reproductive system

Uterus is a pear shaped muscular organ about the size of a fist.  It is designed to nourish and support the developing fetus.  It can stretch to many times its size during pregnancy as the baby grows and contract its powerful muscles to begin the birth process.
The inner lining of the uterus,  Endometrium is composed of blood enriched tissue which drops off or sheds each month during a menstrual period.

Uterus opens into two Fallopian tubes on the upper side as shown in figure. Fallopian tubes serve as the path way of egg from the ovary into the uterus as well as it is in the upper portion of one of these fallopian tubes that fertilization (egg meets the sperm)  takes place. 

The two Ovaries on either side of the uterus store eggs and produce the female sex hormones, estrogen and progesterone which make reproduction possible. The process of ovulation, the release of a matured egg start from the ovaries.  

The Cervix is the entrance to the uterus, also known as the womb. The Vagina is a soft, moist, elastic organ which connect cervix to the outside of the body.  Sperm is released into the vagina during intercourse. 

Normally every woman releases a ripened egg from one or other of her ovaries each month throughout her child-bearing years. On leaving her ovary, the egg is gently guided along the fallopian tube towards the uterus. During this time sperms produced by the male testes leave the penis up on ejaculation during intercourse. The sperms swims up through the cervix and the uterus to the entrance into the fallopian tubes. If the sperm and egg happen to meet in the fallopian tube, the two may become fused to create a single cell. This single cell then begins to divide, eventually implanting itself in the lining on the uterus or womb, to start a pregnancy.