Luteinizing Hormone
Definition
Luteinizing Hormone (LH) is a gonadotropin released by the pituitary gland that triggers ovulation in women. In perimenopause, LH levels can become erratic as ovarian function declines, contributing to irregular cycles.
In Depth
Luteinizing Hormone (LH) is another gonadotropin released by the pituitary gland, working in concert with FSH. In women, LH plays a critical role in ovulation—the release of a mature egg from the ovary. A surge in LH levels, typically occurring mid-cycle, is the direct trigger for ovulation. LH also stimulates the corpus luteum, which forms after ovulation, to produce progesterone.
During the menopause transition, the hormonal feedback loop becomes disrupted, leading to fluctuations in LH levels similar to those seen with FSH. While FSH is more consistently elevated as a marker of ovarian aging, LH can also show variability. These erratic hormonal signals contribute to the irregular menstrual cycles characteristic of perimenopause. For instance, an inadequate LH surge might lead to an anovulatory cycle (a cycle where no egg is released), further contributing to fertility challenges and menstrual irregularities.
LH levels also influence androgen production by the ovaries. While estrogen and progesterone production declines, the relative levels of androgens can sometimes increase, which may contribute to certain symptoms like acne or hair thinning in some women. Understanding LH's role helps clarify the complex hormonal dynamics at play during perimenopause and the eventual cessation of reproductive function. Its interaction with FSH and the ovarian hormones is central to the entire reproductive cycle and its eventual winding down.
Why It Matters
LH levels become erratic during perimenopause, contributing to irregular cycles. Its interaction with FSH and ovarian hormones is central to the reproductive cycle and its eventual winding down.