{"id":3648,"date":"2026-06-10T08:35:52","date_gmt":"2026-06-10T05:35:52","guid":{"rendered":"https:\/\/www.sonerduzguner.com\/?p=3648"},"modified":"2026-06-11T00:20:32","modified_gmt":"2026-06-10T21:20:32","slug":"what-is-fsh-lh-polymorphism","status":"publish","type":"post","link":"https:\/\/www.sonerduzguner.com\/en\/what-is-fsh-lh-polymorphism\/","title":{"rendered":"What Is FSH-LH Polymorphism?"},"content":{"rendered":"
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Genetic Factors Shaping Hormonal Response in IVF Treatment<\/strong>
\nOne of the most common questions I encounter in IVF practice is: \u201cDoctor, why do some women respond so well to the medications while others don\u2019t respond at all?\u201d A significant part of the answer lies in genetics \u2014 specifically, in polymorphisms within the FSH and LH receptor genes.<\/p>\n

In this article, I will explain what FSH-LH polymorphism is, how it affects IVF treatment, and how it guides personalised protocol planning \u2014 in scientific yet accessible language.<\/p>\n

<\/span>FSH and LH: The Fundamental Hormones of IVF<\/span><\/h2>\n

FSH (Follicle-Stimulating Hormone) and LH (Luteinising Hormone) are two key hormones secreted by the pituitary gland that directly regulate the ovaries. In IVF treatment, externally administered FSH preparations stimulate the ovaries to develop multiple follicles. LH contributes to follicle maturation and, through the trigger injection, manages the release of eggs (ovulation).<\/p>\n

But how do these hormones act on cells? The answer: through receptors. FSH and LH bind to specific receptors on the surface of ovarian cells. These receptors are encoded by the FSHR and LHR genes \u2014 and this is precisely where polymorphism comes into play.<\/p>\n

<\/span>2. What Does Polymorphism Mean?<\/span><\/h2>\n

A polymorphism is a hereditary variation in a gene that occurs in at least 1% of the population. In other words, it means carrying a slightly different version of a gene rather than the \u201cstandard\u201d version. This difference may consist of a single DNA base change (SNP \u2014 single nucleotide polymorphism).<\/p>\n

When it comes to FSH-LH polymorphism, these small changes in the FSHR and LHR genes can either increase or decrease the receptor\u2019s sensitivity to the hormone. The result: one woman may develop 15 follicles in response to a standard FSH dose, while another develops only 2\u20133.<\/p>\n

Most Studied FSHR Polymorphisms<\/h4>\n

In the scientific literature, the most extensively studied FSHR polymorphism is a two-point variation located in exon 10 of the gene:<\/p>\n