Endocrine Abstracts

Introduction: In women with GH-secreting pituitary adenoma, a decrease of IGF1 levels has been reported during the first trimester of pregnancy, before placental GH (pGH) secretion inducing a progressive increase in IGF1 levels throughout gestation. This decrease has been related to hepatic GH-resistant state, via JAK2/STAT pathway, due to increased estrogen (E₂) levels.

Objectives: Evaluate IGF1 change in non-acromegalic women during the first trimester of pregnancy.

Patients and methods: Nine women (mean age 30.7±3.9 years) were seen before and during pregnancy in the follow-up of benign thyroid disease. Plasma IGF1, GH, IGF-BP3, TSH and E₂ levels were measured before conception and during the first trimester of gestation (6.7±1.5 weeks of amenorrhea) before the onset of pGH secretion.

Results: Before conception, all women had normal GH/IGF1 secretion and euthyroid function tests (TSH before =1.89±0.95, 1st trimester =1.79±1.17 mU/l). During pregnancy, mean IGF1 levels decreased (before =186±51 ng/ml, 1st trimester =141±44 ng/ml, P<0.05) without significant change in GH (before =2.03±2.01 ng/ml, 1st trimester =1.54±2.34 ng/ml) or IGF-BP3 (before =2.30±0.32 ng/ml, 1st trimester =2.07±0.31 ng/ml) levels while E₂ levels increased (before =56±35 pg/100 ml, 1st trimester =675±820 pg/100 ml, P<0.05).

Conclusion: In this preliminary study we report a significant IGF1 decrease without change in GH and IGF-BP3 concentrations during the first trimester of pregnancy in non acromegalic women. Therefore, as previously reported in acromegalic women, the results suggest the existence of a GH-resistant state due to physiological E₂ secretion in normal pregnant women.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.