A beginning and an end

Menarche, the onset of the menstrual cycle, typically begins between the ages of 8-16 with the average age being 12. As estrogen levels rise during puberty, the young girl will experience her first menstrual cycle (U.S. Dept. of Health and Human Services, 2002). It can take up to one year for the girl to experience a regular 28-day cycle. There are some cases where females continue to have irregular bleeding and the physician may need to prescribe medications to help control or regulate the cycle. Most girls will have a regular 28-day cycle until they become pregnant.
Women will typically experience menses until menopause. The body is no longer producing eggs (ovulating) and the ovaries stop making estrogen which is responsible for thickening the endometrium (American College of Obstetricians and Gynecologists, ACOG, 2007). According to The American College of Obstetricians and Gynecologists, the average age for women to experience menopause is 51 years.
Menarche and menopause is a natural effect of the body, the beginning and the end to the menstrual cycle.

References:
The American College of Obstetricians and Gynecologists. (2007). The menopause years. Retrieved April 8, 2007, from http://www.acog.org/publications/patient_education/bp047.cfm

U.S, Department of Health and Human Services. (2002). Menstruation and the menstrual cycle. Retrieved April 8, 2007, from http://www.4woman.gov/faq/menstru.htm

The 3 Stages

Menstrual phase: Days 1-5
In this phase the uterus sheds the majority of the endometrium. The thick layer of the endometrium detaches from the uterine wall, which causes bleeding for 3-5 days. By the end of the cycle, the ovarian follicles are starting to produce more estrogen (Marieb, 2004).

Proliferative phase: Days 6-14
During this stage the increased estrogen secretion leads to the rebuilding of the endometrium. Ovulation occurs during the end of this phase, day 14. The cervical mucus, which is normally thick and sticky, becomes thin allowing sperm to pass into the uterus (Johnson, 2003).

Secretory phase: Days 15-28
During this phase if the egg becomes fertilized by a sperm the endometrium prepares for implantation of an embryo and the lady becomes pregnant. Once implantation has occurred rising levels of progesterone act on the endometrium allowing nutrients to sustain the embryo (Marieb, 2004). The increased levels of progesterone also create a cervical plug, which blocks sperm entry for the next 9 months.
If fertilization does not occur and the woman is not pregnant, estrogen and progesterone levels drop and the thickened layer of the endometrium prepares itself to shed.

References:
Johnson, L. (Ed.). (2003). Essential medical physiology (3rd ed.). San Diego: Elsevier.
Marieb, E. (2004). Human anatomy & physiology (6th ed.). San Francisco: Pearson Education.

A brief overview

The uterine, or menstrual cycle is a series of changes that the uterine endometruim goes through each month. The body releases hormones, estrogen and progesterone, which account for the changes that take place on a daily basis. Estrogen increase the thickness of the endometrium (the inside lining of the uterus) which causes growth of the endometrium (Johnson, 2003). In turn this growth is accompanied by increased blood flow. This leads to the females monthly bleeding. The average menstrual cycle is 28 days, but can vary anywhere from 23-35 days.

Reference:
Johnson, L. (Ed.). (2003). Essential medical physiology (3rd ed.). San Diego: Elsevier.

About Me!

I'm a Senior Nursing School student and will be graduating on May 5, 2007. I can't wait! I love nursing and could not see myself doing anything else. After graduation I want to be a Labor and Delivery nurse. I think it is important for females to understand all the bodily changes that occur during the menstrual cycle and how pregnancy happens. I hope that this blog will help you understand "the cycle" and clarify what exactly takes place inside the uterus during your cycle.