In Extremely Low Reserve, Where Every Single Egg Is Precious… What Does Growth Hormone Change? Growth Hormone Helps the “Follicular Environment”
Among patients with Diminished Ovarian Reserve (DOR) preparing for In Vitro Fertilization (IVF), those with extremely low ovarian reserve—often called “extreme DOR”—ask the most frequently, “Is there any way to increase my chances of pregnancy, even a little bit?”
For women with extremely low AMH levels, those from whom only one or two eggs were retrieved in previous cycles, or those who have repeatedly failed to produce embryos, a single egg is literally a hope for pregnancy. For patients who do not want to miss even the smallest possibility, one auxiliary treatment chosen by some fertility specialists is Growth Hormone (GH). While it is easy to think of it as an injection to help children grow taller based on its name, growth hormone used in fertility treatment serves a completely different purpose.
Growth hormone is secreted by the pituitary gland located at the base of the brain. While it promotes the growth of height, bones, and muscles during childhood, it continues to be involved in various bodily functions in adulthood, such as protein synthesis, fat metabolism, cellular regeneration, and tissue recovery.
Recently, it has been discovered that receptors for growth hormone and Insulin-like Growth Factor-1 (IGF-1) exist in the ovaries. This has led to successive studies suggesting that growth hormone may influence follicular growth and the egg maturation process. IGF-1, which is produced in the liver stimulated by growth hormone, is known as a key factor that aids the growth and recovery of various tissues.
Many patients ask, “If I take growth hormone, will more eggs be created?” The answer is no. Women are born with all the eggs they will use in their lifetime, and treatment to create new eggs is currently impossible with modern medicine. Growth hormone is also not a drug that creates new eggs or makes the ovaries “younger.”
Instead, it is a treatment aimed at helping the remaining eggs grow in a better environment. In other words, it is more accurate to understand it not as an injection that “grows” eggs, but as a treatment that makes the “soil” in which the eggs grow a little healthier.
Inside the follicle, there are granulosa cells that surround the egg and deliver nutrients and signals. Growth hormone is known to have the potential to activate the functions of these cells and help follicles respond better to Follicle-Stimulating Hormone (FSH), thereby promoting egg maturation. Studies have also been published suggesting that it can improve the function of mitochondria, which are responsible for egg energy production, and reduce oxidative stress, having a positive impact on maintaining cellular function. Ultimately, growth hormone is closer to a “quality control” strategy for eggs rather than a way to increase the number of eggs.
In fact, some studies have reported that in “extreme DOR” patients who used growth hormone adjunctively, the ratio of mature eggs increased, fertilization rates and the formation rate of high-quality embryos improved, and the number of cases leading to embryo transfer increased. There are also quite a few studies where patients who previously had few eggs retrieved or whose embryos repeatedly stopped developing during growth experienced better results than before. For these reasons, growth hormone is consistently used, particularly for patients with repeated poor ovarian response or older fertility patients.
However, growth hormone should not be accepted as a panacea. Synthesizing research published to date, it may be helpful for some patients, but the same effect is not seen in all patients. Results are inconsistent because the age, ovarian function, dosage used, and duration of administration of the subject patients differ in each study. While some studies reported increased pregnancy and birth rates, others failed to find significant differences.
Therefore, the current stance of the reproductive medicine community is relatively cautious. Growth hormone has the potential to be involved in egg energy metabolism and its safety appears relatively high, allowing it to be used supplementally, but it is not a treatment that reverses egg aging or guarantees pregnancy on its own.
Nevertheless, the reason fertility specialists are interested in growth hormone is clear. While there is no way to create new eggs, if it is possible to improve the energy production capacity of the remaining eggs even slightly, it could be helpful. This is especially true for women preparing for pregnancy with extreme DOR or advanced age, where “egg quality” becomes a more important issue than “egg quantity.”
Ultimately, growth hormone is not a miracle drug, nor should it be dismissed as a simple health supplement. Fertility researchers are paying attention to it because it targets the mitochondria—the power plant of the egg—rather than the nucleus of the egg. As the flow of infertility research is expanding from a hormone-centric approach to one focused on cellular energy metabolism and mitochondrial function, more research results regarding growth hormone are expected in the future.
One fertility specialist explained, “An egg is essentially a cell that runs on energy. There is sufficient possibility that mitochondrial health affects egg quality, but rather than placing excessive expectations on a single supplement, overall health management—including weight control, exercise, sleep, and smoking cessation—must accompany it.”
The essence of infertility treatment is not solved by a single drug; it is a process of finding the most suitable strategy for the patient, and growth hormone is one of those strategies.