Luteinizing hormone: What role does LH play in fertility?

LH stands for luteinizing hormone. Like the follicle-stimulating hormone, FSH (and others), LH is produced by specialized cells in the pituitary gland. Its principal function lies in inducing ovulation. Following a sudden spike in LH production, one or more follicles will ovulate (i.e., release an egg). This function of LH is mimicked when patients are given an hCG shot to trigger ovulation during ovarian stimulation in fertility treatments.

Luteinizing hormone (LH) plays a role in ovulation in women. Image from Wikimedia Commons; Author: OpenStax College; License: Creative Commons Attribution 3.0 Unported

LH blood test at fertility centers

LH blood test is a routine part of infertility workup, as well as monitoring during ovarian stimulation, as LH has importance in diagnostics and IVF cycle management..

LH levels can signal fertility problems

For example, a classical diagnostic feature of PCOS is the so-called FSH/LH inversion. This means that the usual ratio between these two hormones, which favors FSH, is inverted, and the LH values exceed FSH values. A patient who presents with such an inversion can almost automatically be assumed to have PCOS.

Finally, since LH is responsible for ovulation, it is not surprising that, together with rising progesterone levels, rising LH levels can also be used to look out for premature ovulation during ovarian stimulation cycles. If progesterone and/or LH suddenly rise to significant levels, one can assume spontaneous ovulation has occurred and the stimulation cycle is, likely lost, because once the developing eggs are released, they cannot be retrieved for IVF.

Using luteinizing hormone in fertility treatments

Whether LH administration is required during ovarian stimulation or stimulation with FSH alone does equally well has remained controversial. Considerable evidence suggests that the answer to this question is age-dependent, with younger women doing just fine if only stimulated with FSH, but older women and women with premature ovarian aging (POA) appearing to benefit from LH as part of their stimulation. A large majority of CHR’s patients, therefore, do receive LH in their stimulation, though the preponderance of stimulation even in those patients is with FSH.

There is, of course, much more to this very important hormone, which we will gladly address if there are further questions coming to our attention.

This is a part of the February 2019 CHR VOICE.

Norbert Gleicher, MD

Norbert Gleicher, MD, FACOG, FACS

Norbert Gleicher, MD, leads CHR’s clinical and research efforts as Medical Director and Chief Scientist. A world-renowned specialist in reproductive endocrinology, Dr. Gleicher has published hundreds of peer-reviewed papers and lectured globally while keeping an active clinical career focused on ovarian aging, immunological issues and other difficult cases of infertility.

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