Menstruation

• Menstruation occurs between the ages of nine and 13. The first menstrual cycle actually begins approximately two weeks before the first period starts. Before the first period arrives, the pituitary gland releases a hormone that signals the uterus to create an environment that is suitable for an embryo to grow in. This environment consists of a uterine lining of tissue and a small amount of blood. A few days later, the ovaries release at least one egg; this is called ovulation. If the egg is fertilized, it will implant itself onto the uterine wall. If it is not a period, or shedding of the tissue and blood through the vagina, will occur.
  
  

Ovulation

• A person who has not experienced her first period has no way of knowing if she has ovulated. Since ovulation occurs before menstruation, if the girl has sex while she is ovulating, she may get pregnant. Since the girl does not know that she should have gotten her period, she may not realize that she is pregnant until she begins to show.
  
  

Risks

• Pregnancy without a period poses risks to mother and baby alike. She may miss the opportunity to terminate the pregnancy. Furthermore, her continued sexual activity places her at risk for contracting a sexually transmitted disease, which may harm the baby as well. This is especially poignant since a person who does not know she is pregnant will not receive prenatal care.
  
  

Menopause

• Women who believe they are menopausal share the same pregnancy risks as non-menstruating girls. Women can go months without a period and attribute it to menopause. These women may actually be relieved that they can now enjoy unprotected sex with their spouses, only to discover that they must have ovulated because they pregnant.
  
  

Prevention

• Abstinence is the only way to be certain that pregnancy will not occur. Any sexually active person who does not want to become pregnant should be using birth control every time. Women should also know the symptoms of pregnancy, such as tender breasts and morning sickness, as opposed to the symptoms of puberty or menopause.