If a woman and a man have unprotected sexual intercourse, sperm that is ejaculated from the man's penis may reach the egg in the fallopian tube. If one of the sperm cells penetrates the egg, the egg is fertilized and begins developing. The egg takes several days to travel down the fallopian tube into the uterus. After it is in the uterus, a fertilized egg usually attaches to implants in the lining of the uterus endometrium.
But not all fertilized eggs successfully implant. If the egg is not fertilized or does not implant, the woman's body sheds the egg and the endometrium. This shedding causes the bleeding in a woman's menstrual period. When a fertilized egg does implant, a hormone called human chorionic gonadotropin hCG begins to be produced in the uterus.
This is the hormone that a pregnancy test measures. It prevents the uterine lining from being shed, so the woman does not have a period. Other signs such as breast changes and nausea occur in a woman's body, also meaning that pregnancy has begun.
Author: Healthwise Staff. Oestrogen works to thicken the wall of your uterus in preparation for pregnancy. On day seven of your cycle, the follicles stop growing except for one. This follicle continues to grow and to nourish a maturing egg oocyte within. On day 12 the maturing follicle releases a burst of oestrogen into the blood stream.
The oestrogen travels through your blood. When the oestrogen reaches the pituitary gland in your brain, the pituitary gland responds by releasing the luteinising hormone.
This hormone gives the follicle a sudden growth spurt. Right before ovulation, the egg inside the follicle detaches itself. The follicle starts to release chemicals that encourage the nearby fallopian tube to move closer and surround the follicle. The follicle swells until it bursts open, ejecting the egg and fluid into the abdominal cavity.
Small finger like protrusions at the end of the fallopian tube, called fimbriae, sweep across the burst follicle and pick up the egg. The egg is transported to the entrance of the fallopian tube.
Once inside the walls of the fallopian tube, muscle contractions push the egg gently towards the uterus. The egg will either meet sperm on its journey through the fallopian tube and fertilisation will happen, or it will arrive in the uterus unfertilised and be absorbed back into the body. If one of the sperm cells penetrates the egg, the egg is fertilized and begins developing. The egg takes several days to travel down the fallopian tube into the uterus.
After it is in the uterus, a fertilized egg usually attaches to implants in the lining of the uterus endometrium. But not all fertilized eggs successfully implant. If the egg is not fertilized or does not implant, the woman's body sheds the egg and the endometrium.
This shedding causes the bleeding in a woman's menstrual period. When a fertilized egg does implant, a hormone called human chorionic gonadotropin hCG begins to be produced in the uterus. This is the hormone that a pregnancy test measures. It prevents the uterine lining from being shed, so the woman does not have a period. Other signs such as breast changes and nausea occur in a woman's body, also meaning that pregnancy has begun.
Author: Healthwise Staff. This information does not replace the advice of a doctor.
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