[Insulin secretion and resistance during pregnancy in women with glucose intolerance]

To investigate whether insulin secretion and resistance are different in glucose tolerant and intolerant women with normal pre-pregnant body mass index (BMI) during late pregnancy and to find out if there is association between gestational diabetes and insulin resistance syndrome.

On the basis of a 4-hour oral glucose tolerance test (OGTT), 32 gestational diabetes mellitus (GDM) patients, 21 gestational impaired glucose tolerant (GIGT) patients, and 50 normal glucose tolerant (NGT) cases were selected from uncomplicated pregnant women. Those had normal pre-pregnant BMI who had a 1-hour 50-g glucose-screening test (> or = 7.2 mmol/L), performed between 24-28 weeks of gestation. During the OGTT, several indexes of insulin resistance, insulin secretion, lipid metabolism were measured in addition to the standard glucose measurements.

Glucose area under curve (GAUC), insulin area under curve (IAUC), insulin sensitivity index (ISI) transformed to natural logarithm and triglycerides (TG) are all significantly higher (P < 0.05) in GDM women. The means of these indexes in GDM group are 26.3 mmol/L.h-1, 276.5 mU/L.h-1, 4.2 and 3.2 mmol/L, respeetively. On the other hand, however, the differences of these indexes (except TG) between GIGT and NGT women are not statistically significant. The ratio of IAUC/GAUC has an increasing trend from GDM group, GIGT group to NGT group (10.5, 11.4 and 11.7, respectively), but the difference is not statistically significant. Multiple correlation coefficient study demonstrated that ISI is significantly positively correlated with GAUC, IAUC and TG (P < 0.01).

Compared with NGT women, GDM women has impaired insulin secretion, abnormally increased insulin resistance, and relatively dyslipidemia. GDM seems to be a component of the syndrome of insulin resistance that provides an excellent model for study and prevention in a relatively young aged group.