Changes in insulin sensitivity and insulin secretion during pregnancy and post partum in women with gestational diabetes.

INTRODUCTION: The metabolic abnormalities underlying gestational diabetes mellitus (GDM) include increased insulin resistance and beta cell defects, but it is essential to clarify how insulin resistance and insulin secretion develop post partum in order to decide when and how to screen for type 2 diabetes. The purpose of the present study was to characterize and compare changes in insulin sensitivity, insulin secretion and hormonal status around parturition and 6 months post partum in women with gestational diabetes. RESEARCH DESIGN AND METHODS: A longitudinal experimental study was performed at Aarhus University Hospital, Denmark. Eight women with GDM were examined at three identical visits: in late pregnancy (LP) between gestational age 34+0 and 36+6, early post partum (EPP) between 12 and 34 days post partum, and late post partum (LPP) 6 months post partum. An intravenous glucose tolerance test was performed, followed by a hyperinsulinemic euglycemic clamp. Blood samples were collected to assess metabolic, hormonal and inflammatory markers at each visit. RESULTS: First and second phase insulin secretion and C-peptide concentrations were higher in late pregnancy than post partum (p<0.001). Insulin sensitivity index (ISI) was different at all three visits: ISILP=0.03±0.004, ISIEPP=0.09±0.008 and ISILPP=0.07±0.008) (p<0.001). Also, significant changes in lipids, leptin, glucagon, growth hormone and insulin-like growth factor-1 were seen when comparing the visits. CONCLUSIONS: Insulin sensitivity improves immediately after delivery in women with GDM but seems to deteriorate within the first 6 months post partum. Our findings underline the importance of having an increased awareness of the profound risk of developing type 2 diabetes after GDM. TRIAL REGISTRATION NUMBER: NCT02770079.

"High prepregnancy HbA1c is challenging to improve and affects insulin requirements, gestational length, and birthweight".

BACKGROUND: The aim of this study was to explore how prepregnancy glycosylated hemoglobin (HbA1c) affects the course of HbA1c and insulin requirements during pregnancy, the gestational length, and birthweight. METHODS: An observational cohort study was conducted consisting of 380 women with type 1 diabetes who gave birth 530 times from 2004 to 2014. The participants were divided into four groups according to prepregnancy HbA1c. RESULTS: HbA1c was significantly different between the groups at all time intervals from week 5 to 10 to week 33 to 36 (P ≤ .01). In group 1, with the lowest prepregnancy HbA1c (<6.5% [48 mmol/mol]), HbA1c stayed at the same level throughout pregnancy. In the other groups (group 2: 6.5% [48 mmol/mol]-7.9% [63 mmol/mol], group 3: 8% [64 mmol/mol]-9.9% [86 mmol/mol], and group 4: > 10% [86 mmol/mol]) a decrease in HbA1c was seen in early pregnancy but stabilized from midpregnancy onward. Group 1 had the lowest daily insulin requirements throughout pregnancy among the four groups (P = .001). The relationship between birthweight and prepregnancy HbA1c was found to be inversely U-shaped. Mean gestational length in group 4 was significantly shorter than in group 1 (P = .001). CONCLUSIONS: In this very large cohort, we found that a poor prepregnancy HbA1c is a predictor for poor glycemic control during pregnancy and that HbA1c decreases until midpregnancy and then plateaus. A very poor prepregnancy HbA1c is associated with shorter gestational length and lower birthweight, which is contrary to the common assumption that poor glycemic control leads to higher birthweight.

Gestational diabetes: A clinical update.

Gestational diabetes mellitus (GDM) is increasing in prevalence in tandem with the dramatic increase in the prevalence of overweight and obesity in women of childbearing age. Much controversy surrounds the diagnosis and management of gestational diabetes, emphasizing the importance and relevance of clarity and consensus. If newly proposed criteria are adopted universally a significantly growing number of women will be diagnosed as having GDM, implying new therapeutic challenges to avoid foetal and maternal complications related to the hyperglycemia of gestational diabetes. This review provides an overview of clinical issues related to GDM, including the challenges of screening and diagnosis, the pathophysiology behind GDM, the treatment and prevention of GDM and the long and short term consequences of gestational diabetes for both mother and offspring.