In normal woman, placental GH secretion increases during gestation and induces an increase of IGF-1 concentrations. In acromegalic women, increased pituitary GH secretion seems autonomous and IGF-1 increases in late stage of pregnancy related to placental GH. In a cohort of 46 women (mean age 31.7±4.5 years), acromegaly was due to micro (n=7) and macro (n=39) adenomas. Before the beginning of 59 pregnancies, women have been treated by transphenoidal surgery (n=47), pituitary radiotherapy (n=2) and medical therapy (dopamine agonists n=25, somatostatin analogs n=14), and GH/IGF-1 hypersecretion was controlled (n=23) and uncontrolled (n=34). A decrease of IGF-1 concentration was observed during the first (12/17), second (13/18) and third (6/9) trimester of gestation. In women with a decrease of IGF-1 concentration during the first trimester of gestation (before 588±207 ng/ml, first trimester 319±126 ng/ml, P=0.002), GH concentration was stable (10%), decreased (55%) and increased (35%). Therefore, the decrease of IGF-1 concentration during the first trimester of pregnancy is not correlated with changes of GH levels (before 5.8±4.2 ng/ml, first trimester 5.2±4.9 ng/ml). In such acromegalic women, the decrease of IGF-1 concentration may be related to increased estrogen levels resulting in a relative hepatic GH-resistance state. Moreover, pituitary GH secretion of some women may not be entirely autonomous and may be partly sensitive to negative feed back control of IGF-1. In conclusion, serum GH and IGF-1 concentrations show variable profiles during gestation of acromegalic women indicating that monitoring of GH/IGF-1 levels is not mandatory during uneventful pregnancy. On the other hand, decrease of IGF-1 level is possible during gestation implying that medical treatment could be discontinued during gestation of most women with acromegaly.
03 - 07 May 2008
European Society of Endocrinology