·To explore the value of gestational oral lipid tolerance test (OLTT) in predicting the risk of gestational diabetes mellitus (GDM).

·From May 2019 to December 2019, 71 pregnant women were recruited in Shanghai General Hospital. OLTT was performed during 14－20 gestational weeks. Triacylglycerol (TAG), free fat acid (FFA) , and small dense low density lipoprotein (sd-LDL) were tested on an empty stomach in the morning and 2 and 4 h after eating a high-fat meal. According to the oral glucose tolerance test (OGTT), the pregnant women were divided into GDM group (n=22) and control group (n=49). General indicators such as age; and the levels of TAG, FFA and sd-LDL on an empty stomach and after a fat meal (2 and 4 h) were compared between the two groups. According to the median of fasting and postprandial (2 and 4 h) TAG, FFA, and sd-LDL in OLTT, the pregnant women were divided into different groups. OGTT blood glucose (including fasting blood glucose, 1 h blood glucose, and 2 h blood glucose) , homeostatic model assessment for insulin resistance (HOMA-IR) and the incidence of GDM were compared between the groups. The area under curve (AUC) of each indicator against GDM was compared by receiver operator characteristic (ROC) curve.

·There was no statistical difference in general indicators such as age between the GDM group and the control group (P>0.05). The fasting and postprandial (2 and 4 h) TAG, sd-LDL and postprandial 4 h FFA in the GDM group were significantly higher than those in the control group, and the differences were statistically significant (all P<0.05). There was no significant difference between the two groups in fasting and 2 h FFA after meal (both P>0.05). The fasting blood glucose level of the fasting high TAG group was significantly higher than that of the fasting low TAG group, and the difference was statistically significant (P<0.05). However, there was no statistically significant difference in blood glucose at 1 h and 2 h between the two groups (both P>0.05). The fasting blood glucose and 1 h blood glucose of the 2 h high TAG group were significantly higher than those of the corresponding low TAG group, and the differences were statistically significant (both P<0.05). The OGTT fasting and 1 h blood glucose levels of the 4 h high TAG group were significantly higher than those of the corresponding low TAG group, and the difference was statistically significant (both P<0.05). The HOMA-IR of all high TAG groups was significantly higher than that of the corresponding groups (all P<0.05). The HOMA-IR of all high sd-LDL groups was significantly higher than that of the corresponding group (all P<0.05). There was no significant difference in the incidence of GDM between the fasting high TAG group and the fasting low TAG group (P>0.05). After meals (2 and 4 h), the incidence of GDM in pregnant women in the high TAG group was higher than that in the corresponding low TAG group (P<0.05). ROC curve analysis showed that the AUC of 4 h FFA versus GDM was the largest and was statistically significant (P<0.05).

·Glycolipid metabolism in pregnant women is closely related. Pregnant women with GDM already show abnormal lipid metabolism during the second trimester (before OGTT examination). OLTT during 14－20 weeks of gestation can be used as a supplement to fasting blood lipid testing, and has important value in GDM risk prediction, and can identify high-risk of GDM in advance.