Relationship Of Pre-pregnancy Weight And Pregnancy Weight Gain With Pregnancy Insulin Sensitivity

Objectives To analyze the relationships between pre-pregnancy weight, pregnancy weight gain and pregnancy insulin sensitivity.Methods In this study, we chose 384 pregnant women who received antenatal examination regularly in Affiliated Hospital of North China University of Science and Technology from Oct. 2013 to Oct. 2014. We used questionnaire survey to get the basic information. All subjects were asked to follow the 75 g oral glucose tolerance test(OGTT), the insulin(INS) and C-peptide(CP) release test between 24 th and 28 th week of gestation. Among all subjects, 337 cases got normal OGTT, and 47 cases with abnormal OGTT, who were diagnosed as GDM. We calculated the pre-pregnancy body mass index(BMI) and the weight gain from pre-pregnancy to the time of OGTT. Firstly, all subjects were divided into three groups depending on the Pre-pregnancy BMI: athrepsia group(BMI<18.5kg /m2)the ideal body mass group(18.5kg/m2≤BMI<24kg /m2), high body mass group(24kg /m2≤BMI). Secondly, during the middle pregnancy, the reasonable weekly weight gain of each pregnant woman was calculated depended on different pre-pregnancy BMI, BMI<18.5kg/m2, 0.44~0.79kg; 18.5kg/m2≤BMI<24kg /m2, 0.49~0.85kg; BMI≥24kg /m2, 0.28~0.69 kg. And they were divided into three groups according to the weight gain during pregnancy: low weight-gain group, who got weight lower than the appropriate weight range; ideal weight-gain group, who got weight in the appropriate weight range, high weight-gain group, who got weight higher than the appropriate weight range. The difference of the blood glucose, the insulin level, the c-peptide level, HOMA-IR, OGTT-IS,the insulin resistance and the GDM situations of the subjects were compared among the different group. The relationships of pregnancy insulin sensitivity to pre-pregnancy weight and pregnancy weight gain were analyzed by multiple linear stepwise regression respectively.Results 1 Among the three groups of pre-pregnancy BMI: The high body mass group had higher levels than the athrepsia group and the ideal body mass group in each point of OGTT of insulin and c-peptide, it also had higher fasting blood glucose and 1 hour blood glucose level than another two groups(P<0.05 for all). And the ideal body mass group had higher fasting insulin and fasting c-peptide level than the athrepsia group(P<0.05 for all); The higher pre-pregnancy BMI group had the higher HOMA-IR and the lower OGTT-IS(P<0.05 for all); With the pre-pregnancy BMI increased,the risk of IR increased(χ2=38.64,P<0.001), and the risk of GDM increased too(χ2=7.71,P<0.05). The odds ratio of IR in ideal body mass group(OR=7.00, 95%CI: 2.12~23.10) and in high body mass group(OR=22.06, 95%CI: 6.32~77.05) were higher than that in the athrepsia group of pregnant women, and the odds ratio of GDM in high body mass group were higher than that in the athrepsia group of pregnant women(OR=3.93, 95%CI: 1.24~12.50). There were positive correlations between pre-pregnancy BMI and fasting plasma glucose(Beta=0.18, P<0.001), and fasting insulin(Beta=0.37, P<0.001). 2 Among three different weight-gain groups: the high weight-gain group had the higher levels than low weight-gain group and ideal weight-gain group in fasting and 1 hour of insulin and cpeptide.And the high weight-gain group also had the higher levels than low weight-gain group in 2 hour of insulin and c-peptide(P<0.05 for all), but there were no significant differences in three points of blood glucose levels among three groups(P>0.05); The high weight-gain group had the higher levels of HOMA-IR and the lower levels of OGTT-IS than another two groups; With the pregnancy weight gain increased, the risk of IR increased(χ2=17.47,P<0.001); The odds ratio of IR in high weight-gain group were higher than that in the low weight-gain group of pregnant women(OR=4.33, 95%CI: 1.98~9.44); There were positive correlations between pregnancy weight gain and fasting insulin(Beta=0.22, P<0.001).Conclusions 1 With the pre-pregnancy BMI increased, the sensitive of insulin were reduced, moreover the risk of insulin resistance were increased. There were positive correlations in pre-pregnancy BMI to fasting plasma glucose and fasting insulin. 2 Pregnant women who gained weight beyond the reasonable range would have lower insulin sensitivity, and in the time their risk of insulin resistance were increased. There were positive correlations between pregnancy weight gain and fasting insulin.