Conception

During the first half of the menstrual cycle two chemical substances called hormones are released from special glands into the bloodstream. One hormone stimulates the process that results in the production of an ovum, or ripe egg. The other hormone stimulates the endometrium, or lining of the uterus (womb), to thicken in readiness to receive a fertilized ovum. About two weeks from the end of your menstrual cycle the work of the first hormone is completed and you ovulate; that is, a ripe ovum is released from one of your ovaries.

Conception occurs if your partner's sperm fertilizes this ovum. This usually takes place in the Fallopian tube that connects the ovary to the uterus. The fertilized ovum completes its journey to the uterus, where it implants into the thickened uterine lining. Once this process occurs the cervix increases slightly in width and becomes softer, and a thick mucous plug seals off the uterus to protect it from infection. After two weeks, if there has been no conception, the thickened uterine lining is shed and menstruation takes place.

Fertilization