From the Guidelines
In PCOS, the typical hormonal pattern shows elevated LH (luteinizing hormone) levels and normal to low FSH (follicle-stimulating hormone) levels, resulting in an increased LH to FSH ratio often greater than 2:1, as indicated by a study published in the Journal of Neurology, Neurosurgery and Psychiatry 1. The hormonal imbalance in PCOS contributes to the characteristic symptoms, including irregular menstruation, excess androgen production, and ovulatory dysfunction.
- Key features of PCOS include:
- Elevated LH levels, often greater than 11 IU/l, as shown in Table 2 of the study 1
- Normal to low FSH levels, with a ratio of LH to FSH greater than 2:1
- Insulin resistance, which further exacerbates the hormonal dysfunction by increasing androgen production and disrupting normal ovarian function
- Blood tests for LH and FSH are typically performed during the early follicular phase (days 3-6) of the menstrual cycle for the most accurate assessment, as recommended in the study 1. The hormonal imbalance in PCOS is a critical aspect of the condition, and understanding the typical patterns of LH and FSH levels is essential for diagnosis and management.
- It is essential to note that not all women with PCOS will show the classic hormonal pattern, and approximately 30-50% may have normal LH:FSH ratios.
- The study published in the Journal of Neurology, Neurosurgery and Psychiatry 1 provides valuable insights into the hormonal abnormalities associated with PCOS, highlighting the importance of considering LH and FSH levels in the diagnosis and management of the condition.
From the Research
PCOS, FSH, and LH Levels
- In women with polycystic ovary syndrome (PCOS), hormonal imbalances, including FSH and LH levels, play a crucial role in the development of the condition 2, 3.
- Studies have shown that treatments such as metformin, letrozole, and gonadotropins can affect FSH and LH levels in women with PCOS 4, 2, 3, 5.
- For example, a study found that metformin plus letrozole significantly reduced testosterone, fasting insulin, and fasting glucose/fasting insulin ratio, while bilateral ovarian drilling significantly reduced FSH, LH, and LH/FSH ratio 2.
- Another study found that letrozole and metformin combined with targeted nursing care decreased LH levels and increased FSH levels in infertile patients with PCOS 3.
- The use of gonadotropins, such as recombinant FSH (rFSH), has also been shown to affect FSH and LH levels in women with PCOS, although the evidence is not always consistent 4.
Treatment Options
- Various treatment options are available for women with PCOS, including lifestyle modifications, metformin, letrozole, gonadotropins, and surgical interventions such as bilateral ovarian drilling 6, 4, 2, 3, 5.
- The choice of treatment depends on individual factors, such as the presence of insulin resistance, obesity, and ovulation status 6, 4, 2, 3, 5.
- Letrozole has been shown to be an effective treatment for inducing ovulation in women with PCOS, particularly in those who are resistant to clomiphene citrate 5.
- Gonadotropins, such as rFSH, may also be used to induce ovulation in women with PCOS, although the evidence is not always consistent 4.
Hormonal Changes
- Hormonal changes, including changes in FSH and LH levels, are a key aspect of PCOS treatment 2, 3.
- Treatments such as metformin, letrozole, and gonadotropins can affect FSH and LH levels, leading to improvements in ovulation and fertility outcomes 4, 2, 3, 5.
- However, the evidence is not always consistent, and further research is needed to fully understand the effects of different treatments on FSH and LH levels in women with PCOS 4, 2, 3, 5.