Changes in the Uterus During Perimenopause

During a woman's fertile years, the process of menstruation prepares the uterus to house and nourish life. As their bodies age, women enter the stage known as perimenopause brought about by physical and chemical changes related to the cessation of the reproductive function. These changes usually begin at approximately 30 to 40 years of age and last until menopause, which occurs one year after the last menstrual period. Changes occurring in the uterus during perimenopause may initially be manifested by an erratic menstrual cycle and mood swings related to fluctuating ovarian hormone levels.

Menstrual Cycle

• As part of the menstrual cycle, two hormones, estrogen and progesterone, are produced by the ovaries, according to the Taylor Medical Group. Estrogen prepares the lining of the uterus (endometrium) for pregnancy by causing it to thicken, facilitating implantation of a fertilized egg. If pregnancy does not occur, progesterone enables the detachment of the lining, which is then discarded in the form of blood and tissue debris during menstruation. In perimenopause, hormone production gradually diminishes and the menstrual cycle becomes irregular. Skipped periods are common during the months when estrogen production is minimal.

Ovarian Function

• Prior to perimenopause, follicles in the ovaries develop into eggs and are released into the uterus each month during the menstrual cycle. This process, called ovulation, occurs as the result of hormones produced by the endocrine system and transported by the bloodstream to the ovaries. Follicle stimulating hormone (FSH) assists in the development of the egg, and luteinizing hormone (LH) triggers its release from the ovary into the uterus.

  During perimenopause, ovulation no longer occurs on a regular basis and eventually stops as a result of the diminishing response of aging follicles to FSH and LH, as stated by MSN Encarta in an article on menopause.

Fallopian Tubes

• The fallopian tubes are attached to the uterus and extend to the ovaries. During ovulation, an egg is released from the ovary and enters the fallopian tube where it remains for approximately one week after fertilization before beginning its journey to the uterus. If the egg is not fertilized before reaching the uterus, pregnancy does not occur and the unfertilized egg dissolves within the uterus. As women enter perimenopause, signaling the approach of the end of their reproductive years, the supply of viable follicles has diminished.

Pregnancy

• Missed periods and erratic menstrual cycles during perimenopause are only the beginning of the cessation of the female reproductive function. The misconception that women are no longer fertile at this time has resulted in many unexpected pregnancies. It remains possible for pregnancy to occur until at least one year has passed since the last menstrual period, usually between the ages of 45 to 55.

Medication

• Many women do not experience any adverse symptoms during perimenopause. For others, the symptoms can range from mild to severe. On their website, St. John Health System lists the types of medications available for helping to alleviate problems such as irregular periods, decreased interest in sex, and mood swings. They suggest discussing the symptoms with a physician who may recommend birth control pills, hormone replacement therapy, or antidepressants. MSN Encarta offers other suggestions: exercise, vitamins, smoking cessation, and dietary changes to combat these symptoms.