Anovulatory bleeding: This condition is common in young women and is characterized by irregular menstrual periods due to the absence of ovulation. The frequency of periods can vary, and it often presents with irregular, heavy, or light bleeding.

Hormonal imbalance: Imbalances in estrogen and progesterone levels can lead to irregular menstrual cycles. This could be due to various factors, including polycystic ovary syndrome (PCOS), thyroid disorders, or the use of hormonal contraceptives.
Stress or weight changes: Significant stress or changes in weight can disrupt the normal menstrual cycle, leading to more frequent periods.
Uterine polyps or fibroids: Although less common in young women, these conditions can cause irregular menstrual bleeding.

Pregnancy complications: Although the patient's temperature is slightly elevated, it's crucial to rule out a pregnancy, especially an ectopic pregnancy, which can present with irregular bleeding and is a medical emergency.
Infection or sepsis: The slightly elevated temperature could indicate an underlying infection. Pelvic inflammatory disease (PID) or other infections could cause irregular bleeding and require prompt treatment.
Bleeding disorders: Conditions like von Willebrand disease or other coagulopathies can lead to heavy or frequent menstrual bleeding.

Premature ovarian failure: Although rare, premature ovarian failure can cause irregular menstrual periods.
Adrenal or pituitary gland disorders: Certain disorders affecting these glands, such as Cushing's syndrome or a pituitary tumor, can lead to hormonal imbalances causing irregular menstrual cycles.
Thyroid cancer or other endocrine cancers: These are rare but can cause hormonal imbalances leading to menstrual irregularities.