oligomenorreia

Oligomenorrhea is a menstrual disorder characterized by infrequent menstrual periods, defined as cycle lengths greater than 35 days and fewer than about nine menses in a year. It reflects reduced frequency of ovulation in many cases, but can also occur with irregular cycle patterns that do not fit a normal 21–35 day cycle.

Common causes include physiological states (adolescence during maturation of the hypothalamic–pituitary–ovarian axis; perimenopause), polycystic ovary syndrome (PCOS), thyroid disorders, and hyperprolactinemia. Functional hypothalamic amenorrhea due to energy deficit, excessive exercise, or stress can present with oligomenorrhea. Other contributors include obesity or significant weight change, chronic illnesses, certain medications, ovarian or pituitary disorders, and pregnancy must be excluded in all evaluations.

Evaluation typically starts with a careful history and physical examination, followed by pregnancy testing. Laboratory testing may include thyroid-stimulating hormone (TSH), prolactin, and gonadotropins (FSH, LH) as indicated by age and presentation. Androgen levels may be measured if signs of hyperandrogenism are present. A progesterone challenge (withdrawal bleed) test helps assess estrogen status and the presence of anovulation. Pelvic ultrasound may be considered to evaluate ovarian morphology and structure, particularly when PCOS or other pathology is suspected.

Management targets the underlying cause and the patient’s goals, such as regular menses or fertility. Options include lifestyle modification for weight and exercise, hormonal contraception (combined estrogen–progestin or progestin-only regimens) to regulate cycles and protect the endometrium, and treatment of metabolic or endocrine disorders (e.g., thyroid disease, hyperprolactinemia). For PCOS-related oligomenorrhea, metformin and insulin-sensitizing strategies may be used, and ovulation induction with agents such as letrozole or clomiphene may be pursued for fertility. Prognosis varies with cause and treatment; prolonged unopposed estrogen exposure can raise endometrial cancer risk and metabolic complications in some conditions.