Menstruation
Before talking about disorders involving menstruation, it is important to understand how normal menstruation occurs.
A normal menstrual cycle starts with menstruation and the follicular phase (days 0-13), which ends with ovulation on day 14. Estrogen is the dominant hormone in the follicular phase, during which the dominant follicle is selected, leading to a size increase. At the same time, the uterine endometrium thickens. On day 14, ovulation occurs, which is caused by a luteinizing hormone (LH) surge. This causes the rupture of the ovarian follicle, which releases the mature ovum. The luteal phase (days 15-28) begins with the LH surge and ends at the start of the next menses, which is considered day 1 of the next cycle. During the luteal phase, progesterone becomes the dominant hormone. If no fertilization and implantation occur, LH decreases, which causes a decrease in progesterone. This leads to sloughing of the endometrial lining, which is a menstrual period.
One variation of normal menstruation that is common in young women is Mittelschmerz, which presents in the middle of the menstrual cycle, corresponding with ovulation. This is a natural and normal phenomenon but does not go unnoticed. People who experience Mittelschmerz report acute onset, unilateral lower quadrant pain. Since this symptom can be a danger sign for something more serious, women experiencing this will often seek medical treatment. Pregnancy testing and transvaginal ultrasound are performed as part of the initial evaluation for acute, unilateral abdominal pain in a reproductive-aged woman. In the case of Mittelschmerz, reassurance is provided, since this is normal and dissipates without intervention.
Premenstrual Disorders
Premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD) are most seen in women in their 20s and are characterized by a combination of psychological (e.g., anxiety, irritability, decreased interest) and physical (e.g., bloating, breast tenderness, fatigue) manifestations. A menstrual (symptom) diary is used to confirm the diagnosis before initiating treatment.
Dysmenorrhea and Abnormal Bleeding
Primary dysmenorrhea is suspected when a patient has lower abdominal pain and gastrointestinal symptoms during the first 2-3 days of menses with a normal physical examination that doesn’t suggest anything underlying that needs to be treated. NSAIDs are typically used as first-line pharmacotherapy, but combination oral contraceptive pills can be used as an alternative when NSAIDs are ineffective or cannot be used. Other uses of combination oral contraceptive pills include birth control, abnormal uterine bleeding, adenomyosis, endometriosis, fibroids, and polycystic ovary syndrome.
Moderate uterine bleeding refers to bleeding longer than 7 days or frequent menses occurring every 1 to 3 weeks, with moderate to heavy flow and hemoglobin above 10 g/dL. Combination oral contraceptive pills are the first-line treatment. An alternative therapy of progestin-only therapy is used in those with contraindications (e.g., migraine headaches).
Adenomyosis is endometrial glands and stroma within the myometrium. It can present with heavy menstrual bleeding, dysmenorrhea, and a pelvic ultrasound showing globular uterine enlargement and cystic anechoic spaces in the myometrium. The definitive treatment is hysterectomy.
Anovulation and Amenorrhea
Anovulatory bleeding or bleeding without ovulation is common in the first few years after menarche, the onset of menstruation, and during perimenopause. In the first few years after menarche, it is the result of an immature hypothalamic-pituitary-ovarian axis resulting in inadequate progesterone production. The first line therapy for anovulatory cycles and resultant heavy bleeding in the postmenarchal period is a combined estrogen-progesterone oral contraceptive.
Primary amenorrhea or lack of menstruation can be due to hypothalamic-pituitary-ovarian axis disorders. Hypothalamic dysfunction can be due to functional hypothalamic amenorrhea (caused by excessive exercise or low BMI) or gonadotropin-releasing hormone (GnRH) deficiency. Kallman syndrome is a genetic disorder characterized by a defect in GnRH production and anosmia (impaired sense of smell). Because of this GnRH defect, patients have prepubertal levels of sex steroids and do not undergo puberty. Presenting features can include primary amenorrhea and absent breast development.
Ovarian dysfunction can be due to chemotherapy/radiation (e.g., alkylating agents and pelvic radiation are frequently toxic to ovaries) and gonadal dysgenesis. Turner syndrome is a condition in which all or part of one of the X chromosomes is missing. The most common genotype is 45, X. In Turner syndrome, genitalia develop normally; however, primordial follicles undergo accelerated ovarian failure, causing primary amenorrhea, and infertility. A lack of gonadal estrogen causes failed breast development. Most patients with Turner syndrome demonstrate several classic physical findings including a webbed neck, shield chest, and short stature.
Secondary amenorrhea is absent menses for over 3 months in a patient who previously had regular cycles. Initial evaluation would look at prolactin, TSH, FSH, and an assessment of estrogen status, commonly done via a progestin withdrawal test. PCOS can present with secondary amenorrhea, normal prolactin, normal TSH, normal FSH, and a progestin withdrawal test that yields withdrawal bleeding, indicating a normal estrogen level).
Primary ovarian insufficiency is defined as the cessation of ovarian function before age 40. It is characterized by decreased estrogen production and can cause oligomenorrhea, secondary amenorrhea, and infertility. As a result of a loss of feedback inhibition, low estrogen leads to increased production of GnRH and FSH from the hypothalamus and pituitary gland, respectively.
Metabolic Disorders
Polycystic ovarian syndrome (PCOS) often involves excessive hair growth, weight gain, cystic ovaries on pelvic ultrasound, elevated FSH (follicle-stimulating hormone), and elevated androgens. Patients are at increased risk for endometrial hyperplasia and endometrial cancer due to the unopposed effects of estrogen. Patients are at increased risk for diabetes mellitus, which is why people diagnosed with PCOS should be screened regularly for insulin resistance.
Pituitary dysfunction can be due to Cushing syndrome, which is characterized by irregular fat accumulation, skin changes, weight gain, and elevated blood pressure. A prolactinoma is a tumor of the anterior pituitary gland, which can cause hyperprolactinemia, headache, visual field changes, and elevated prolactin. It is diagnosed with an MRI brain that would show a mass. Hyperprolactinemia leads to galactorrhea and suppresses GnRH, which results in low levels of FSH and LH. As a result, anovulation and oligomenorrhea (infrequent or irregular menstruation) or amenorrhea occur.
Other metabolic disorders can also affect menstruation. Thyroid disorders can present with abnormal HR, weight changes, nail and hair changes, and elevated or low thyroid-stimulating hormone (TSH). Exogenous androgen use presents with acne, abnormal hair growth, mood changes, and a history of performance-enhancing drugs.