From the Guidelines
The laboratory workup for irregular menses should include a pregnancy test, complete blood count, thyroid-stimulating hormone (TSH), prolactin level, and assessment of androgen levels (total and free testosterone, DHEAS) as recommended by recent guidelines 1. Additional testing should include follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol to evaluate ovarian function. If polycystic ovary syndrome is suspected, consider adding hemoglobin A1c or fasting glucose and lipid panel, as metformin may improve menstrual cyclicity and hyperandrogenism in these patients 1. For patients with suspected premature ovarian insufficiency, anti-Müllerian hormone may be helpful. Transvaginal ultrasound can complement laboratory testing by evaluating endometrial thickness and ovarian morphology, which is particularly useful in identifying polycystic ovarian morphology (PCOM) that may be present in up to 46.7% of women with functional hypothalamic amenorrhoea 1. This comprehensive approach helps identify common causes of menstrual irregularity such as pregnancy, thyroid dysfunction, hyperprolactinemia, PCOS, and premature ovarian insufficiency. Early diagnosis allows for appropriate management, whether that involves addressing underlying hormonal imbalances or providing contraceptive therapy to regulate cycles. For patients concerned about fertility, prompt identification of the cause of irregular menses is particularly important as some conditions may impact reproductive potential if left untreated. Key considerations in the workup and management of irregular menses include:
- Evaluating for polycystic ovary syndrome in female adolescents with type 2 diabetes, including laboratory studies, when indicated 1
- Using metformin, in addition to lifestyle modification, to improve menstrual cyclicity and hyperandrogenism in female individuals with type 2 diabetes 1
- Considering the potential for polycystic ovaries and hyperandrogenaemia in women with epilepsy, particularly those treated with valproate 1
- Distinguishing between functional hypothalamic amenorrhoea (FHA) with PCOM and polycystic ovary syndrome (PCOS), which can be challenging but is crucial for appropriate management 1.
From the Research
Irregular Menses Lab Work Up
The lab work up for irregular menses may involve various tests to determine the underlying cause of the irregularity.
- Hormonal imbalance: Tests such as thyroid function tests (TFTs) may be ordered to check for hyper- or hypothyroidism, as both conditions can cause menstrual disturbances 2.
- Anovulation: Laboratory tests may be conducted to check for anovulation, which is a common cause of irregular menses, especially in adolescents due to an immature hypothalamic-pituitary-ovarian axis 3.
- Other tests: Additional tests such as complete blood count (CBC) to check for anemia, and other tests to rule out other underlying medical conditions such as metabolic syndrome, coronary heart disease, type 2 diabetes mellitus, and rheumatoid arthritis may be ordered 4.
Possible Causes of Irregular Menses
The possible causes of irregular menses include:
- Hormonal imbalance: Changes in the body's levels of estrogen and progesterone hormones can disrupt the normal pattern of the period 4.
- Thyroid disorders: Both hyper- and hypothyroidism can cause menstrual disturbances, including oligomenorrhea, amenorrhea, and polymenorrhea 2.
- Immature hypothalamic-pituitary-ovarian axis: In adolescents, anovulation due to an immature hypothalamic-pituitary-ovarian axis can cause menstrual irregularity 3.
Evaluation and Diagnosis
Evaluation and diagnosis of irregular menses involve a careful history, physical examination, and selected laboratory tests to determine the underlying cause of the irregularity and to rule out other underlying medical conditions 4, 2, 3.