The Effect of Growth Hormone on Ovarian Response for In Vitro Fertilization

Growth hormone has been postulated to improve ovarian response, increasing the number of oocytes retrieved and eggs fertilized, in patients undergoing in vitro fertilization (IVF). Growth hormone as an adjuvant to IVF has been previously investigated, however ovarian response outcomes have been conflicting. Some studies show no increase in ovarian response while others show an increase in oocytes retrieved and positive pregnancy tests, but not an increase in live birth rates. Due to conflicting outcomes, this study explored whether a growth hormone adjuvant to IVF would increase ovarian response in patients with previously poor ovarian response defined as less than 3 oocytes retrieved. This retrospective study was from October 2022 to October 2023 and a total of 24 female participants ages 32 to 46 years old were included. In order for participants to meet criteria for this study they had poor ovarian response in at least one previous IVF cycle, defined by less than or equal to 3 follicles, with subsequent cycle(s) using a growth hormone adjunct. Using a within subject design, participants in this study acted as their own controls using the data from their IVF cycle without growth hormone (control) and with growth hormone (experimental). The growth hormone was injected subcutaneously and ranged from 25units daily for 4 weeks to 2-3 units daily for 1-2 months. Additional medications used for the ovarian stimulation protocol included gonadotropins, GnRH agonist or antagonist, and a human chorionic gonadotropin. Variations in the medications chosen were based on the outcome of prior IVF cycles and poor ovarian response. The primary study outcome was the number of oocytes retrieved and fertilized. The secondary study outcomes were the total follicles, follicles greater than 15mm, and the embryo quality. Decision was made to include follicles greater than 15 mm in size because they likely reached maturity. After statistical analysis, the number of follicles greater than 15 mm and the total number of follicles with and without adjuvant growth hormone were not statistically different (P value of 0.268 and 0.085, respectively). In addition, the number of oocytes retrieved and fertilized with and without the addition of growth hormone were not statistically different (P value of 0.327 and 0.11, respectively). Lastly, the number of quality embryos with and without adjuvant growth hormone was not statistically significant (P value of 0.85). These findings suggest that human growth hormone adjuvant may not be beneficial in improving ovarian response. Prior similar research has conflicting results regarding the benefits of human growth hormone on ovarian response and these studies are often underpowered. Some of this is postulated to be secondary to the nature of the participants who already have poor pregnancy prognosis and no established dose and duration of growth hormone treatment. Akin to other studies, this study also had a small sample size. However, in the setting of a within subject design, as this study used, a smaller sample size is often still able to detect a causal relationship. Another benefit of the use of a within-subject design in this study, is that individual variations are removed and therefore it is more statistically powerful. While this study contributes to the ongoing debate surrounding the efficacy of growth hormone in fertility treatments, it also highlights the complexity of factors influencing IVF success. Further research with larger sample sizes and more controlled methodologies (standardization of growth hormone dose and duration of treatment) may be necessary to explore this topic more comprehensively.