Glucagon stimulation test: assessment of beta-cell function in gestational diabetes mellitus

OBJECTIVE

Because women with gestational diabetes mellitus have a risk of up to 60% for the later development of type II diabetes, we used the intravenous glucagon stimulation test to evaluate beta-cell function in pregnant women.

PATIENTS

Twenty-seven pregnant women with one or more risk factors for gestational diabetes had an intravenous beta-cell stimulation test. Glucose, C-peptide and insulin levels were measured at baseline and 5, 10 and 15 min after the administration of 1 mg glucagon. The women were classified using the 75-g oral glucose tolerance test according to World Health Organization criteria. During the oral glucose tolerance test glucose, C-peptide and insulin levels were measured at baseline and at 2 h.

RESULTS

Insulin and C-peptide responses were significantly lower in pregnant women with impaired glucose tolerance and diabetes compared with women with normal glucose tolerance.

CONCLUSION

This study shows gradually decreasing insulin secretion from normal to subnormal in pregnant women without and with glucose intolerance, and diabetes mellitus, respectively.

The 1-h 50-g glucose challenge does not predict large-for-gestational-age infants

The relationship between the 1-h 50-g glucose challenge performed at 24-28 weeks and subsequent birth of a large-for-gestational-age infant was examined in a cohort of 368 Europid women who had no pre-existing medical condition and experienced no pregnancy complications. The results established that the 1-h 50-g glucose challenge blood glucose level had no predictive power with respect to the birth of a large-for-gestational-age infant. However, the 1-h blood glucose value was found to be significantly related to maternal height, weight and age, indicating that its level also represents processes unconnected to glucose intolerance. The study findings also re-confirmed the importance of parity, height, sex, and weight as determinants of large-for-gestational-age infants.