The biological basis of menopause and the years preceding is well established, being dependent on changes in ovarian structure and function. The biology underlying the transition to menopause includes not only the profound decline in follicle numbers of the ovary but also a significant increase in random genetic damage within the ovaries [5]. As a result, the ovaries undergo a major shrinkage, so that while premenopausal ovaries are 3–4 cm in size, after menopause they can be measured approximately 0.5–1.0 cm with a fairly smooth tan-white appearance [6]. The older one woman gets, the smaller her ovaries become, but they never disappear. Regarding ovarian function, throughout menopausal transition up to menopause, it is noticed that there is an increased prevalence of anovulatory cycles, leading progressively to definite cessation of ovarian function.

After menopause the uterus becomes smaller, although the degree of shrinkage is less in the cervix than in the rest of the uterus [7]. The endometrium is no more affected by the monthly production of female hormones and becomes atrophic. The tissues that make up the cervix generally become thinner and less robust, and the transformation zone where the type of cervical lining changes tends to move higher and slightly inside the endocervical canal [8]. This change makes this zone more difficult to examine on a special visual exam of the cervix, called a colposcopy. The endocervical canal or opening into the uterus may also become narrower or even close completely, a situation called cervical stenosis. This is usually not a problem, because regular menstruation ceases once a woman has become menopausal, so menstrual flow no longer needs to drain out of the uterus.

The cervical glands and the cells that line the endocervical canal make mucus in response to the female hormones that are produced by the ovary during the menstrual cycle. After menopause, when a woman’s ovaries stop making these hormones, these cells and glands produce less mucus, often leading to dryness in the vagina, where mucus normally acts as a lubricant.

Both the vagina and the external female genitalia (vulva) are affected by shifting levels of hormones (especially estrogen) during menopausal transition. Before menopause, when the vagina is well supplied with estrogen, its lining is thicker and has more folds, allowing it to stretch with intercourse and childbirth [9]. After menopause, when levels of estrogen are low, the vaginal lining gets thinner with fewer folds, which makes it less elastic or flexible. Concomitantly, the vaginal walls become atrophic, more easily irritated, and drier, as vaginal secretions are reduced, resulting in decreased lubrication [7]. Reduced levels of estrogen also result in an increase in vaginal pH, which makes the vagina less acidic, just as it was before puberty.

Along with vaginal atrophy, the tissues of the vulva become thinner and drier as well leading to a condition known as “vulvovaginal atrophy.” Following menopause, pubic hair grays and becomes sparse, the labia majora loses subcutaneous fat, and the labia minora, vestibule, and vaginal epithelium atrophy [10, 11]. At the cytological level, estrogen-induced parakeratosis of vulvar stratum corneum is highest in the third decade of life, but rarely seen by the eighth decade [12]. At the same time, pubic muscles can lose tone resulting in the vagina, uterus, or urinary bladder falling out of their position (uterine prolapse, cystocele, rectocele).

Menstrual irregularity occurs in more than one-half of all women during menopausal transition [14]. Uterine bleeding can be irregular, heavy, or prolonged. In most cases, this bleeding is related to anovulatory cycles. This disruption of normal menstrual flow has been attributed to a gradual decrease in the number of normally functioning follicles and is reflected by a gradual increase in early follicular-phase FSH levels [15]. The cessation of menstruation indicates that the amount of estrogen produced by the ovaries is no longer enough to promote endometrial proliferation and the absence of cyclic progesterone production is accompanied by the absence of withdrawal bleeding [16].

Although anovulation is one of the more common causes of abnormal uterine bleeding, pregnancy must always be considered. There are numerous reports of pregnancies in women in their late 40s who did not consider themselves fertile. In these women, abnormal bleeding may be the first indicator of an unexpected pregnancy [17].

Endometrial cancer should be suspected in any perimenopausal women with abnormal uterine bleeding. After menopause, the overall incidence of endometrial cancer is approximately 0.1 % of women per year, but in women with abnormal uterine bleeding, it is about 10 % [18, 19]. Malignant precursors such as complex endometrial hyperplasia become more common during the menopausal transition. Other causes that should be considered when a woman experiences abnormal uterine bleeding include cervical cancer, polyps, or leiomyomata.

With the advent of newer diagnostic modalities, vaginal ultrasonography has become an established first step in the evaluation of perimenopausal bleeding. An endometrial stripe <5 mm thick has been shown to be associated with an extremely low risk of endometrial hyperplasia or cancer [20–22]. A thickened or asymmetric endometrial lining or an obvious intrauterine lesion is an indication for more thorough evaluation [20].

Because early diagnosis is the most effective way to improve a woman’s prognosis, perimenopausal women with abnormal uterine bleeding should undergo an endometrial biopsy to exclude a malignant condition. Although vaginal ultrasonography has changed the way patients with abnormal uterine bleeding are evaluated, endometrial biopsy continues to be the most accurate screening method available for these patients. Dilation and curettage in the operating room with adequate anesthesia should be reserved for patients with abnormal endometrial biopsies or for conditions that preclude performing an office biopsy, such as cervical stenosis. The addition of hysteroscopy to uterine curettage has greatly improved diagnostic accuracy in the evaluation of focal intrauterine lesions [23, 24]. It allows for visual inspection of the endometrial cavity and gives the physician the opportunity to perform directed biopsies [24]. Endometrial polyps or submucosal leiomyomas that are commonly seen in perimenopause can easily be identified by hysteroscopy.

Alternatively, in the absence of uterine pathology, intermittent doses of progestogen may be helpful for women who are having intermittent bleeding and who are not ovulating, while some women find it helpful to take nonsteroidal anti-inflammatory pain relievers such as ibuprofen and naproxen [25]. An intrauterine device, which secretes a low dose of the progestogen, levonorgestrel, can help control excess or unpredictable bleeding caused by irregular ovulation or hormonal problems.

With the increased use of imaging and the recognition by primary care doctors that ovarian cancers present with subtle symptoms, more ovarian masses are being detected in postmenopausal women. In screening studies, 5–20 % of women over the age of 50 with no other symptoms will have an ovarian mass detected on ultrasound [26]. However, only a percentage of these will prove to be ovarian cancer after surgery. Thus, it is important to distinguish ovarian cysts that can be monitored with repeat ultrasound studies from masses that need to be surgically evaluated due to their elevated risk of early ovarian cancer.

Transabdominal and transvaginal ultrasound have become a mainstay for the evaluation of pelvic masses due to their low cost and minimal invasiveness [27]. When reviewing ultrasound reports, there are five characteristics that are important in differentiating ovarian cysts with a low likelihood of harboring an ovarian cancer from masses with a higher risk. These characteristics are the size, the complexity of the cyst, the presence of solid areas, projections into the fluid called papillations, and the ovarian blood flow as measured by color Doppler assessment.

In postmenopausal women with simple ovarian cysts less than 5 cm, the risk of an ovarian cancer is very small (0–1 %) [28]. The risk for developing ovarian cancer in women with simple ovarian cysts less than 10 cm in diameter is extremely low. However, 10–40 % of complex cysts with solid areas and papillations will harbor a malignancy.

CA125 is a blood test that can be performed to help the physician to determine the risk of ovarian cancer [29]. The higher the level of CA125, the more it is likely that an ovarian mass is malignant. However, CA125 is elevated above normal in only 50 % of patients with Stage 1 ovarian cancer and may miss half of the patients with a localized tumor. On the other hand, an elevated CA125 is nonspecific and can be elevated in the face of many common benign findings.

A magnetic resonance imaging (MRI) of the ovary is not diagnostic for cancer; however, it is very sensitive for benign ovarian masses such as dermoids or uterine fibroids that can be confused with ovarian masses. Thus, MRIs should be reserved for patients with indeterminate ultrasound findings who cannot have surgery because of the costs, the need for intravenous dye, and claustrophobia of the machine.

Treatment of ovarian cysts has been made more convenient with the introduction of laparoscopy in the 1980s. Simple cysts less than 5 cm in diameter without concerning features can safely be followed with repeated ultrasounds. Other ovarian masses should be referred to gynecologic oncologists for appropriate surgery, which may include laparoscopic removal of the ovaries with staging procedure if necessary.

Although a woman no longer has menstrual periods after menopause, it is still important for her to visit a gynecological specialist regularly, because an exam that includes a Papanicolaou smear can still detect many possible problems after menopause. In this test, a doctor obtains a tissue sample from the surface of the cervix. A Papanicolaou test can detect cervical cancer, which is the ninth leading cause of cancer deaths for American women and is more often diagnosed at a later stage in older women. This type of cancer is almost always caused by the human papillomavirus.