Hormonal counterregulation and subjective symptoms during induced hypoglycemia in insulin-dependent diabetes mellitus patients during and after pregnancy.

BACKGROUND: The objective was to elicit whether hormonal responses to and subjective symptoms of hypoglycemia are modified during pregnancy in patients with insulin-dependent diabetes mellitus.
METHODS: In ten type I diabetic women, hyperinsulinemic hypoglycemic clamps, with target arterial blood glucose content of 2.2 mmol/l, were performed during the third trimester of pregnancy and 5-13 months after delivery. The levels of arterial glucose and venous catecholamines, pituitary growth hormone, cortisol, glucagon, dehydroepiandrosterone and free insulin were assessed repeatedly. Subjective symptoms of hypoglycemia were recorded on a visual analog scale. The paired t-test and Wilcoxon signed rank test were used for statistical comparisons.
RESULTS: Adrenaline and dehydroepiandrosterone increased during hypoglycemia on both occasions, but dehydroepiandrosterone disclosed a significantly different pattern of response during pregnancy (p=0.016). The cortisol increase was augmented during pregnancy (420+/-50 vs. 310+/-30 nmol/l non-pregnant, p=0.039), while the increase in pituitary growth hormone (hGH) was diminished (5.4+/-1.2 vs. 27.9+/-5.4 microg/l non-pregnant, p=0.001), but nevertheless the increase during pregnancy was significant (p=0.002). Three of the eight subjective symptoms of hypoglycemia recorded were less prominent during pregnancy, namely 'inability to concentrate' (p=0.03), 'headache' (p=0.01) and 'pounding heart' (p=0.03).
CONCLUSIONS: Albeit some subjective symptoms were diminished during pregnancy, the study gives no evidence that, in diabetic patients, pregnancy per se impairs the counterregulatory response to hypoglycemia, with the exception of growth hormone. However, despite the suppressed basal growth hormone secretion in late pregnancy, the study disclosed a secretory response of this hormone at hypoglycemia.