Measuring IGF-1 and IGFBP-3 profiles in women seeking assisted reproduction; relationship to serum growth hormone levels (Study 3)

Extending from our first two studies examining the IGF profile (IGF-1, IGFBP-3 and the ratio of IGFBP-3/ IGF-1) in women presenting for assisted reproductive technologies (ART), this study examines its relevance to the testing of human growth hormone (hGH) levels on the same blood sample. These were taken in the morning during the early follicular phase of the woman’s menstrual cycle and included 408 women who were ART-naïve, undertaking the tests as part of an assessment cycle prior to any ART treatment. The growth hormone levels were also tested on a further 945 women classified as ART-interval cases. It was shown that the vast majority of hGH levels (73%) were very low at <1.0 ng/mL and 22% are extremely low <0.1 ng/mL, close to the detection level of the chemiluminescent immunoassay (0.03 ng/mL). Only 12% of hGH levels were recorded in the range ≥3.0 ng/mL, levels which exclude adult growth hormone deficiency (AGHD). Although IGF-1 levels are regarded as a screening test for AGHD, our studies showed no correlation between hGH levels and the entire range of IGF-1 levels, neither across IGFBP-3 levels, nor across IGF Ratios, albeit there was an apparent inverse trend for the latter. Across the entire age range, the hGH levels were not statistically different among neither the ART-naïve nor the ART-interval women. Furthermore, hGH levels were not different among the clinical parameters of stature or BMI; nor for ovarian reserve parameters AMH or AFC. It is concluded that serum hGH screening probably has very limited value as a screening test for potential AGHD.