Before Birth Control ... Understanding Your Body
Vagina: where the penis enters during sex and from where the baby exits during birth.
Uterus: a hollow muscle in the shape of a pear where the baby grows during pregnancy.
Cervix: the base of the uterus and the part that opens or dilates during childbirth to allow the baby to come out during childbirth.
Ovaries: organs at the sides of the uterus that produce eggs.
Fallopian tubes: connect the ovaries with the uterus and through which the egg travels to the uterus.
The menstrual cycle lasts an average of 28 days (it can last more or less). To know the length of your cycle, count from the first day of your period in one month to the first day of your period the next month.
Hormones are chemical substances in the body that cause different changes to the body, including the following during the menstrual cycle:
- The cycle starts with the bleeding (menstruation) which lasts two to seven day.
- The ovary prepares to release an egg.
- An egg is released from the ovary around day 14, it could be before or after that.
- This egg travels down the fallopian tube toward the uterus.
- At the same time, a layer of tissue forms and thickens on the wall of the uterus.
- If the egg does not join with a sperm, it starts to disintegrate together with the layer of tissue and it leaves the body through the vagina. This is menstruation.
When a man ejaculates during sex, the semen with sperm leaves the man's penis and enters the woman's body through the vagina. Some semen may still enter the vagina even if the man ejaculates outside of the vagina.
If an egg has been released by the ovaries (ovulation), it can join with the man's sperm. This is called fertilization. Pregnancy starts when a fertilized egg is implanted in the uterus.
Important: sperm can live inside a woman for up to five days. This means that if a woman has not ovulated when she has sex, she could still get pregnant in the next few days.
For more health information, search MedlinePlus
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Last updated: May 2013