Oral Glucose Tolerance Test In Pregnancy Research Articles

Outcome of pregnancy oral glucose tolerance test and preterm birth.

Gestational diabetes is associated with adverse outcomes such as preterm birth (<37 weeks). However, there is no international consensus on screening criteria or diagnostic levels for gestational diabetes, and it is unknown whether body mass index (BMI) or obesity modifies the relation between glucose level and preterm birth. We studied a pregnancy cohort restricted to two Danish regions from the linked Danish Medical Birth Register to study associations between glucose measurements from the 2-hour post-load 75-gram oral glucose tolerance test (one-step approach) and preterm birth from 2004-2018. In Denmark, gestational diabetes screening is a targeted strategy for mothers with identified risk factors. We used Poisson regression to estimate rate ratios (RR) of preterm birth with z-standardized glucose measurements. We assessed effect measure modification by stratifying analyses and testing for heterogeneity. Among 11,337 pregnancies (6.2% delivered preterm), we observed an adjusted preterm birth RR of 1.2 (95% CI: 1.1-1.3) for a 1 standard deviation glucose increase of 1.4 mmol/L from the mean 6.7 mmol/L. There was evidence for effect measure modification by obesity, e.g., adjusted RR for non-obese (BMI <30): 1.2 (95%CI: 1.1-1.3) vs. obese (BMI ≥30): 1.3 (95%CI: 1.2-1.5), P=0.05 for heterogeneity. Among mothers screened for gestational diabetes, increased glucose levels, even those below the diagnostic level for gestational diabetes in Denmark, were associated with increased preterm birth risk. Obesity (BMI ≥30) may be an effect measure modifier, not just a confounder, of the relation between blood glucose and preterm birth risk.

Hypoglycaemia following the 2-hour 75g OGTT in pregnancy – Investigating maternal and foetal outcomes

AimsTo investigate differences in maternal and foetal outcomes in pregnancy, where patients developed hypoglycaemia following the 2-hour 75g oral glucose tolerance test (OGTT). MethodA retrospective cohort study of 200 pregnancies attending the Antenatal Clinic at Tameside General Hospital between 2018 and 2022. Outcomes were compared between 4 groups: normal OGTT [G1; (n = 39, 20%), diagnosis of gestational diabetes mellitus (GDM) based on OGTT [G2; BG ≥ 5.6 mmol/L or 2-h OGTT ≥7.8 (n = 41, 21%)], hypoglycaemia [G3; 2 h OGTT 3.0–3.9 mmol/L (n = 93, 47%)], or clinically significant hypoglycaemia [G4; 2 h OGTT <3.0 mmol/L (n = 27, 14%)]. Maternal BMI, foetal birth weight (FBW), neonatal complications, neo-natal intensive care unit (NICU) stay and conversion to GDM were assessed. ResultsMaternal BMI was lower in G3 and G4 (27.3 kg/m2 and 28.1 kg/m2 respectively) compared to G1 (30.4 kg/m2) (p = 0.02). NICU stay was more frequent in G3 (12%, n = 11) and G4 (8%, n = 2) compared to G1 (5%, n = 2). Foetal complications occurred in 27% of G3 (n = 25) and 33% of G4 (n = 9) compared to 23% in G1 (n = 9) and 17% in G2 (n = 7). FBW was similar in G1 when compared to G3 and G4 (p = 0.34). Of the 120 patients in G3 and G4, 25 patients self-monitored blood glucose for two weeks; 28% (n = 7) subsequently developed GDM. ConclusionHigher rates of NICU stay and foetal complications were seen in both hypoglycaemic groups. In patients with hypoglycaemia following OGTT there is evidence to support self-monitoring blood glucose as 28% were later diagnosed with GDM.

Previous High-Intensity Breastfeeding Lowers the Risk of an Abnormal Fasting Glucose in a Subsequent Pregnancy Oral Glucose Tolerance Test.

Breastfeeding is associated with reduced lifetime cardiometabolic risk, but little is known regarding the metabolic benefit in a subsequent pregnancy. The primary aim of this study was to investigate the association between breastfeeding duration and intensity and next pregnancy oral glucose tolerance test (OGTT) results. A retrospective cohort study was conducted from March 2020 to October 2022. All multiparous women who met inclusion criteria and gave birth during the study period were eligible for inclusion. Analysis was stratified by risk for gestational diabetes (GDM). High GDM risk criteria included previous GDM and BMI > 35 kg/m2. The association between breastfeeding duration and high-intensity breastfeeding (HIBF) and subsequent pregnancy OGTT were assessed with multivariate logistic models adjusted for statistically and clinically relevant covariables. There were 5374 multiparous participants who met the inclusion criteria for analysis. Of these, 61.7% had previously breastfed for >6 months, and 43.4% were at high risk for GDM. HIBF was associated with 47% reduced odds of an abnormal fasting glucose in a subsequent pregnancy OGTT (aOR 0.53; 95%CI 0.38-0.75; p < 0.01). There was no association between HIBF and other glucose results on the OGTT. Women who smoked were least likely to breastfeed at high intensity (aOR 0.31; 95%CI 0.21-0.47; p < 0.01). South Asian women had 65% higher odds of HIBF than women who identified as White/European (aOR 1.65; 1.36-2.00; p < 0.01). This study highlights the importance of exclusive breastfeeding to potentially reduce the prevalence of GDM and may also translate into long-term reduction of cardiometabolic risk.

178-LB: Association of Pregnancy Oral Glucose Tolerance Test (OGTT) Glucose Response with Metabolic Profile in Mother and Child—Hyperglycemia and Adverse Pregnancy Outcomes Follow-up Study (HAPO-FUS)

The glucose response shape during an OGTT, monophasic or biphasic, can characterize physiologically distinct groups with differences in insulin secretion and sensitivity. Biphasic response (glucose rebound after nadir ≥ 0.025 mmol/L) has been associated with higher insulin sensitivity and β-cell function. We aimed to identify the association of the pregnancy OGTT response shape with follow-up maternal and offspring metabolic profiles. Method: Using HAPO-FUS study data from the NIH-NIDDK repository, monophasic glucose response was defined as 2-hr glucose - 1-hr glucose &amp;lt; 0. Multiple linear regression assessed the relationship of glucose response shape with maternal profile at 10-year follow-up and offspring metabolic profile at 10-12 years of age. Maternal covariates include age, gestational age, field center and BMI. Child covariates include age, sex, pubertal stage, and family history of diabetes. Results: 4,605 mothers (83.7% monophasic) and 3792 children were included. Mothers with monophasic shape were older (30.7 vs 29.8 years, p=.002), had higher BMI (26.7 vs 26.0 kg/m2, p=.003), HbA1c (4.80 vs 4.70 %, p &amp;lt;.001), 1-hour c-peptide level (9.60 vs 7.75 ug/dL, p &amp;lt;.001) and gestational diabetes (14 vs 9.5%, p &amp;lt;.001). At 10-year follow-up, pregnancy monophasic response was associated with higher fasting glucose level (0.06 [0.01, 0.11], p =.01) and log HOMA-IR (0.06 [0.02, 0.10], p=.007) in mothers at follow-up. Offspring had higher cord c-peptide (0.12 [0.04, 0.21], p=.005) and body fat percent (1.35 [0.50-2.21], p =.002). Offspring insulin sensitivity (-0.17 [-0.04, -0.3], p=.01) and Matsuda index (-0.46 [-0.15, -0.76], p=.003) were lower with monophasic response. Conclusion: Maternal glucose response profiles during pregnancy determined by both insulin secretion and whole-body insulin resistance are associated with long-term maternal and offspring metabolic profile. Disclosure V. V. Thaker: None. C. A. Leduc: None. R. Salem: Other Relationship; Travere Inc. Funding National Institutes of Health (K23DK110539)

Reactive hypoglycaemia during the OGTT after gestational diabetes mellitus: Metabolic implications and evolution.

Gestational diabetes (GDM) presents an increased cardio-metabolic risk and is diagnosed with an oral glucose tolerance test (OGTT). Reactive hypoglycaemia (RH) during the OGTT in pregnancy is associated with adverse outcomes. Although postpartum OGTT after GDM is recommended, the occurrence and implications of RH are unknown. We investigated the prevalence, metabolic implications and longitudinal evolution of RH at 6-8 weeks postpartum in women with a history of GDM. Between 2011 and 2021, we consecutively followed 1237 women with previous GDM undergoing an OGTT at 6-8 weeks postpartum. RH was defined as 2-h glucose <3.9 mmoL/L after the OGTT. Metabolic outcomes were compared in women with and without RH (RH+/RH-). We also included a subcohort of 191 women with data on insulin sensitivity/secretion indices (MATSUDA, HOMA-IR, insulin-adjusted-secretion ISSI-2). The postpartum prevalence of RH was 12%. RH+ women had a more favourable metabolic profile including a 2-5-times lower prevalence of glucose intolerance and metabolic syndrome at 6-8 weeks postpartum compared to RH- (all p ≤ 0.034). In the subcohort, women with RH+ had higher insulin sensitivity, higher ISSI-2 and an earlier glucose peak after OGTT (p ≤ 0.049) compared to RH- women at the same time point. Insulin resistance increased and ISSI-2 decreased over the first year postpartum in both groups. These changes were associated with a 50% reduction in overall RH prevalence at 1-year postpartum. Some of the favourable profiles of RH+ persisted at 1-year postpartum, without group differences in the longitudinal metabolic changes. At 6-8 weeks postpartum, RH was frequent in women after GDM and associated with a better metabolic profile including increased insulin sensitivity and higher insulin-adjusted-secretory capacity. RH might be a marker of favourable metabolic prognosis in women with a history of GDM.

Continuous Glucose Monitoring in Women with Normal OGTT in Pregnancy.

Continuous glucose monitoring (CGM) might be an effective tool to improve glycemic control in gestational diabetes mellitus (GDM). Few data are available about its utilization as a diagnostic tool to find potential alterations of glycemia in subjects with normal oral glucose tolerance test (OGTT). In this preliminary prospective real-life observational study, we aimed to analyze the glycemic pattern in normal and gestational diabetes mellitus (GDM) women by continuous glucose monitoring (CGM) in order to detect potential differences between the two groups and glycemic alterations despite a normal OGTT. After the screening for GDM, subjects were connected to a CGM system for seven consecutive days. The areas under the curve of the first 60 minutes after each meal and 60 minutes before breakfast were analyzed. Women with normal OGTT that during CGM showed impaired glycemic values (more than 95 fasting or more than 140 one hour after meals or more than 120 two hours after meals) performed one week of self-monitoring of blood glucose (SMBG). After OGTT, 53 women considered normal and 46 affected by GDM were included. CGM parameters did not show any differences between the two groups with impaired glycemic excursions found in both groups. After CGM period, 33 women with normal OGTT showed abnormal glycemic patterns. These 33 women then performed one week of SMBG. After evaluation of one week of SMBG, 21 required diet therapy and 12 required insulin treatment and were followed until the delivery. An increase in gestational weight gain was observed in normal women with normal OGTT but this was not significant. No significant data were found regarding neonatal outcomes in the two groups of women. In conclusion, CGM use in pregnancy might help to detect glycemic fluctuations in women with normal OGTT, improving their treatment and outcomes.

955-P: Postpartum Carbohydrate Intake Is Not Associated with Oral Glucose Tolerance Test Results

Background: In pregnant and postpartum (PP) women, an oral glucose tolerance test (OGTT) is the diagnostic test of choice for glucose intolerance. Consistent with classic studies outside of pregnancy, we recently found that lower carbohydrate intake on the day before an OGTT in pregnancy was associated with higher post-load OGTT glucose. Here, we test for a relationship between carbohydrate intake and OGTT glucose in PP women. Methods: PP women (N=84, median [IQR] = 9 [8-14] weeks PP) completed a 75 g OGTT and a validated self-administered 24-hr dietary recall. We tested for an association between carbohydrate intake in the day before the OGTT and 1-hr OGTT glucose using linear regression, with adjustment for age, race, BMI, time postpartum, and caloric intake. We also tested for associations with 30 minute and 2-hr OGTT glucose and glucose area under the curve (AUC). A subset of women (N=72) had completed the same protocol during pregnancy (median=26 weeks gestation). Results: PP women with lower carbohydrate intake (&amp;lt;median=230 g/day) had similar age, BMI, race, education, GDM status, time postpartum, and time fasting before OGTT to women with higher intake. We found a trend toward higher fasting glucose in those with lower carbohydrate intake (median=87 vs. 81 mg/dl, P=0.09), but no association between carbohydrate intake and post-load OGTT glucose (1-hr: β=1.2 mg/dl, P=0.74, 30 min: β=-2.0 mg/dl, P=0.39, 2-hr: β=1.0 mg/dl, P=0.74, AUC: β=66, P=0.83). Post-load results did not change with fasting glucose adjustment. In women with data available in pregnancy, we found similar results to those previously reported: at ~26 weeks gestation, lower carbohydrate intake was associated with higher OGTT glucose. Conclusion: While carbohydrate intake in the day prior to an OGTT may alter gestational diabetes diagnosis, we found no relationship between carbohydrate intake and OGTT glucose among PP women. Metabolic factors that differentiate the pregnant and postpartum state may account for our findings. Disclosure E. A. Rosenberg: None. E. W. Seely: None. K. James: None. M. J. Callahan: None. S. Nelson: None. C. E. Powe: None. Funding National Institutes of Health (K23DK113218); Robert Wood Johnson Foundation (T32DK007028); Massachusetts General Hospital

Hyperglycemia at 1h-OGTT in Pregnancy: A Reliable Predictor of Metabolic Outcomes?

Gestational diabetes mellitus (GDM) is associated with a high risk of developing type 2 diabetes (T2DM) and cardiovascular disease (CVD). Identifying among GDM women those who are at high risk may help prevent T2DM and, possibly CVD. Several studies have shown that in women with GDM, hyperglycemia at 1 h during an oral glucose tolerance test (OGTT) (1-h PG) is not only associated with an increase in adverse maternal and perinatal outcomes but is also an independent predictor of T2DM. Interestingly, also in pregnant women who did not meet the criteria for a GDM diagnosis, 1-h PG was an independent predictor of postpartum impaired insulin sensitivity and beta-cell dysfunction. Moreover, maternal 1- and 2-h PG levels have been found to be independently associated with insulin resistance and impaired insulin secretion also during childhood. There is evidence that hyperglycemia at 1h PG during pregnancy may identify women at high risk of future CVD, due to its association with an unfavorable CV risk profile, inflammation, arterial stiffness and endothelial dysfunction. Overall, hyperglycemia at 1h during an OGTT in pregnancy may be a valuable prediction tool for identifying women at a high risk of future T2DM, who may then benefit from therapeutic strategies aimed at preventing cardiovascular outcomes.

Relationship between carbohydrate intake and oral glucose tolerance test results among pregnant women

AimsEvaluate the relationship between self-reported carbohydrate intake and oral glucose tolerance test (OGTT) results in pregnancy. MethodsWe measured carbohydrate intake using 24-hour dietary recall and performed a 2-hour 75-gram OGTT in 95 pregnant women with risk factors for gestational diabetes (GDM) at a median of 26 weeks’ gestation. We tested for associations between carbohydrate intake in the 24 hours preceding the OGTT and 60-minute OGTT glucose, glucose at other timepoints, and glucose area under the curve (AUC) using linear regression, with adjustment for potential confounders. ResultsWe observed an inverse linear relationship between carbohydrate intake (median 237 grams [interquartile range: 196, 303]) and 60-minute OGTT glucose. For every 50 gram reduction in carbohydrate intake, there was an 8.9 mg/dl increase in 60-minute OGTT glucose (P < 0.01) in an adjusted model. Lower carbohydrate intake was also associated with higher 30-minute (adjusted β = −6.5 mg/dl, P < 0.01) and 120-minute OGTT glucose (adjusted β = −8.1 mg/dl, P = 0.01) and AUC (adjusted β = −767, P < 0.01). ConclusionsCarbohydrate intake in the day preceding an OGTT in pregnancy is associated with post-load glucose values, with lower carbohydrate intake predicting higher glucose levels and higher carbohydrate intake predicting lower glucose levels. Carbohydrate restriction or excess before an OGTT may affect GDM diagnosis.

Association of glucose metabolism and blood pressure during pregnancy with subsequent maternal blood pressure.

The goal of this study was to examine associations of measures of maternal glucose metabolism and blood pressure during pregnancy with blood pressure at follow up in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) cohort. The HAPO Follow-Up Study included 4747 women who had a 75-g oral glucose tolerance test (OGTT) at ~28 weeks’ gestation. Of these, 4572 women who did not have chronic hypertension during their pregnancy or other excluding factors, had blood pressure evaluation 10–14 years after the birth of their HAPO child. Primary outcomes were systolic blood pressure (SBP), diastolic blood pressure (DBP) and hypertension (SBP ≥140 and/or DBP≥90 or treatment for hypertension) at follow-up.Blood pressure during pregnancy was associated with all blood pressure outcomes at follow-up independent of glucose and insulin sensitivity during pregnancy. The sum of glucose z-scores was associated with blood pressure outcomes at follow-up but associations were attenuated in models that included pregnancy blood pressure measures. Associations with SBP were significant in adjusted models, while associations with DBP and hypertension were not. Insulin sensitivity during pregnancy was associated with all blood pressure outcomes at follow-up, and although attenuated after adjustments, remained statistically significant (hypertension OR 0.79, 95%CI 0.68– 0.92; SBP beta −0.91, 95% CI −1.34– −0.49; DBP beta −0.50, 95% CI −0.81– −0.19).In conclusion, maternal glucose values at the pregnancy OGTT were not independently associated with maternal blood pressure outcomes 10–14 years postpartum; however, insulin sensitivity during pregnancy was associated independent of blood pressure, BMI and other covariates measured during pregnancy.

Investigation of the progress in the women with gestational diabetes mellitus postpartum

Aims: Our aim was to evaluate the uptake of postpartum screening, the prevalence and the risk factors for glucose intolerance in women with a recent history of gestational diabetes mellitus (GDM). Methods: All women with a history of GDM are advised to undergo a 75g oral glucose tolerance test (OGTT) around 6 - 12 weeks postpartum. Indices of insulin sensitivity (the Matsuda index and the reciprocal of the homeostasis model assessment of insulin resistance, HOMA-IR) and an index of beta-cell function, the Insulin Secretion-Sensitivity Index-2 (ISSI-2) were calculated based on the OGTT postpartum. Multivariable logistic regression was used to some factors. Results: Of all women (135) who received an OGTT postpartum, 42.2% (57) had glucose intolerance (11.8% impaired fasting glucose, 24.4% impaired glucose tolerance and 6.0% both impaired fasting and impaired glucose tolerance) and 1.5% (2) had overt diabetes. Compared to women with a normal OGTT postpartum, women with glucose intolerance and diabetes were older (32.5 ± 4.3 vs. 30.8 ± 4.8 years, p = 0.049), were more often obese (34.5% vs. 17.3%, p = 0.023). In the multivariable logistic regression, an EM background [OR = 2.76 (1.15 - 6.62), p = 0.023] and the HbA1c level at the time of the OGTT in pregnancy [OR = 4.78 (1.19 - 19.20), p = 0.028] remained significant predictors for glucose intolerance postpartum. Women with glucose intolerance and diabetes postpartum had a similar insulin sensitivity [Matsuda index 0.656 (0.386 - 1.224) vs. 0.778 (0.532 - 1.067), p = 0.709; HOMA-IR 0.004 (0.002 - 0.009) vs. 0.064 (0.003 - 0.007), p = 0.384] but a lower beta-cell function compared to women with a normal OGTT postpartum, remaining significant after adjustment for confounders [ISSI-2 1.6 (1.2 - 2.1) vs. 1.9 (1.7 - 2.4), p = 0.002]. Conclusions: Glucose intolerance is very frequent in early postpartum in women with GDM these women have an impaired beta-cell function. Nearly one third of women did not attend the scheduled OGTT postpartum and these women have an adverse risk profile. More efforts are needed to engage and stimulate women with GDM to attend the postpartum OGTT.

Risk factors associated with postpartum impaired glucose regulation in women with previous gestational diabetes.

For women with previous gestational diabetes (GDM), international guidelines recommend 75 g oral glucose tolerance test (OGTT) at 4-12 weeks after delivery to assess glucose tolerance, considering their increased risk of type 2 diabetes. We evaluated prevalence of postpartum impaired glucose regulation (IGR) and identified associated risk factors. We retrospectively collected data from 749 women with previous GDM (IADPSG criteria) who underwent postpartum OGTT for type 2 diabetes screening between 2011 and 2019. IGR was identified according to ADA criteria. Prevalence of IGR was 12.7%, lower in women with pre-pregnancy normal weight, higher in women with family history of type 2 diabetes and in those treated with insulin during pregnancy. Prevalence of IGR raised with increasing number of altered glucose values at OGTT performed during pregnancy for GDM screening. HbA1c and triglycerides measured during the third trimester of pregnancy were higher in women with postpartum IGR. At postpartum screening, women with IGR had higher BMI, waist, blood pressure. At multivariate logistic regression analysis, family history of diabetes (OR 2.21; 95% CI: 1.33-3.69; p < 0.01) and presence of all three glucose values exceeding threshold at OGTT during pregnancy (OR 2.89; 95% CI: 1.42-5.86; p < 0.01) were independently associated with IGR. In women with GDM, persistence of IGR in the immediate postpartum period is associated with family history of diabetes and the presence of all three glucose values exceeding diagnostic threshold for GDM at OGTT in pregnancy, suggesting that these women should undergo specific diabetes monitoring and prevention programs.

Gestational diabetes: A link between OGTT, maternal-fetal outcomes and maternal glucose tolerance after childbirth

Background and aimThe relationship among distribution of pathological values at the Oral Glucose Tolerance Test (OGTT), metabolic risk factors and pregnancy outcomes in women with Gestational Diabetes (GDM), has not been clearly identified. We retrospectively compared metabolic and therapeutic parameters, maternal–fetal outcomes and post-partum OGTTs, with respect to the number and distribution of altered values of diagnostic OGTT in pregnancy. Secondly, we assessed whether insulin therapy predictive factors were identifiable. Methods and resultsThis analysis included 602 pregnant women with GDM, followed in Diabetes and Pregnancy Unit of Perugia Hospital from diagnosis to childbirth. All women were diagnosed diabetic upon 75g OGTT, according IADPSG criteria. Women were divided into 3 groups, respect to distribution of diagnostic blood glucose (BG) values at OGTT: Group 1: only fasting BG (OGTT0h); Group 2: 1 and/or 2h (OGTT1-2h); Group 3: both fasting and 1 h and/or 2h (OGTT0+1–2h) BG.Pregnant women with fasting hyperglycemia at OGTT (Groups 1 and 3) had similar metabolic characteristics (weight, prevalence of obesity, gestational weight gain, HbA1c), a greater need for insulin therapy, and a higher risk of impaired glucose tolerance persistence after childbirth, as compared to Group 2. No significant differences were observed in terms of maternal and neonatal outcomes (p > 0.05), except for a greater prevalence of caesarean sections in Group 3. ConclusionThe metabolic characteristics of GDM women are mirrored by OGTT values at diagnosis, but are not associated with adverse pregnancy outcomes. Intensive management and a tailored treatment of GDM improve maternal-neonatal outcomes, regardless of diagnostic values distribution and pre-gestational metabolic characteristics.

1380-P: Pregravid A1C and Glucose Measurements to Rule Out Gestational Diabetes and Reduce the Need for Oral Glucose Tolerance Testing in Pregnancy

The recommendation of universal screening for gestational diabetes (GDM) by oral glucose tolerance test (OGTT) in pregnancy may pose a resource challenge for healthcare systems. In light of growing recognition that women who develop GDM have chronic metabolic dysfunction that predates their pregnancy, we hypothesized that pre-gravid measurement of A1c and glucose may provide the capacity to rule out GDM in low-risk women and thereby reduce the overall OGTT burden in pregnancy. To test this hypothesis, we identified all women in Ontario, Canada, with singleton live-birth pregnancies between January 2008 and December 2015 (n=1,001,006, of which 47,180 had GDM), and created derivation and validation cohorts (each n=500,503). In the derivation cohort, pre-gravid A1c (OR=9.72, 95%CI 8.76-10.79), fasting glucose (OR=3.32, 95%CI 3.13-3.51) and random glucose (OR=1.70, 95%CI 1.65-1.75) each predicted subsequent GDM. Area-under-receiver-operating-characteristic curve (AROC) was higher for A1c (0.684) than for fasting glucose (0.647) or random glucose (0.625). Test characteristics revealed that the negative predictive value (NPV) for ruling out GDM was optimized (NPV=98.7%) at pre-gravid A1c ≤4.3%. However, when evaluated in the validation cohort, this pre-gravid A1c threshold would only reduce the need for antepartum OGTT in 0.11% of women. Conversely, if test sensitivity for predicting GDM were set at 95.1% in the derivation cohort, the resultant threshold of pre-gravid A1c ≤5.0% would reduce the need for antepartum OGTT in 7.2% of women but at the cost of missing 2.5% of GDM diagnoses in the validation cohort. In conclusion, pre-gravid A1c and glucose levels can predict a woman’s future risk of GDM. However, their test characteristics are clinically not acceptable for reducing the need for GDM screening by OGTT in pregnancy. Disclosure R. Retnakaran: Consultant; Self; Eli Lilly and Company, Novo Nordisk Inc., Sanofi. Research Support; Self; Boehringer Ingelheim International GmbH, Novo Nordisk Inc. B.R. Shah: None.

Incidence and Outcomes of Gestational Diabetes Mellitus Using the New International Association of Diabetes in Pregnancy Study Group Criteria in Hôpital Maisonneuve-Rosemont.

At 1 Canadian university hospital, pregnant women were routinely screened for gestational diabetes mellitus (GDM) with a 75-g oral glucose tolerance test (OGTT). Diagnostic plasma glucose thresholds were as follows: fasting: ≥5.3 mmol/L, 1 h: ≥10.6 mmol/L and 2 h: ≥9.0 mmol/L. In 2015, diagnostic thresholds were reduced to those recommended by the International Association of Diabetes in Pregnancy Study Group (IADPSG) as follows: fasting: ≥5.1 mmol/L, 1 h: ≥10.0 mmol/L and 2 h: ≥8.5 mmol/L. However, subsequent Diabetes Canada guidelines state that further evidence is required before recommending those thresholds. Our objectives were to compare pregnancy outcomes of all pregnant women who underwent a 75-g OGTT before and after the adoption of the IADPSG criteria. Pregnancy outcomes of all women (N=2,830) that had a pregnancy OGTT at the Hôpital Maisonneuve-Rosemont between July 1, 2014 and March 1, 2015 (pre-IADPSG group) were compared with women who were screened between March 1, 2015 and January 1, 2016 (post-IADPSG group). Medical files were reviewed to compare outcomes. Women in the post-IADPSG group had a higher early body mass index (26.3 vs 25.5 kg/m2, p=0.01) and more chronic hypertension (3.7% vs 1.2%, p<0.0001), respectively. OGTT results were similar, but rates of GDM were 10.8% (141 of 1,295) in the pre-IADPSG group and 17.6% (271 of 1,535) in the post-IADPSG group. In the post-IADPSG group, pre-eclampsia rates were lower (1.0% vs 2.2%, p=0.021), as was labour induction (25.6% vs 32.8%, p<0.0001) and neonatal intensive care unit admission (4.8% vs 8.5%, p<0.001), respectively. Adopting IADPSG criteria for GDM improved pregnancy outcomes in our obstetric population.

Seasonality, temperature and pregnancy oral glucose tolerance test results in Australia

BackgroundThe oral glucose-tolerance test (OGTT) is currently the standard method for diagnosis of gestational diabetes (GDM). We conducted a post hoc analysis using the Australian Hyperglycemia and Adverse Pregnancy Outcome (HAPO) data to determine seasonal variations in OGTT results, the consequent prevalence of GDM, and association with select perinatal parameters.MethodWomen enrolled in the Australian HAPO study sites (Brisbane and Newcastle) from 2001 to 2006 were included if OGTT results between 24 to 32 weeks gestation were available (n = 2120). Fasting plasma glucose, 1-h plasma glucose, 2-h plasma glucose, HbA1c, HOMA-IR, and umbilical cord C-peptide and glucose values were categorized by season and correlated to monthly temperature records from the Australian Bureau of Meteorology for Brisbane and Newcastle. GDM was defined post hoc using the IADPSG/WHO criteria.ResultsSmall but significant (p < 0.01 on ANOVA) elevations in fasting glucose (+ 0.12 mM), HbA1c (+ 0.09%), and HOMA-IR (+ 0.88 units) were observed during the winter months. Conversely, higher 1-h (+ 0.19 mM) and 2-h (+ 0.33 mM) post-load glucose values (both p < 0.01) were observed during the summer months. The correlations between fasting glucose, 1-h glucose, 2-h glucose, and HbA1c with average monthly temperatures confirmed this trend, with positive Pearson’s correlations between 1-h and 2-h glucose with increasing average monthly temperatures, and negative correlations with fasting glucose and HbA1c. Further, umbilical cord C-peptide and glucose displayed negative Pearson’s correlation with average monthly temperature, aligned with trends seen in the fasting plasma glucose. Overall prevalence of GDM did not display significant seasonal variations due to the opposing trends seen in the fasting versus 1-h and 2-h post-load values.ConclusionA significant winter increase was observed for fasting plasma glucose, HbA1c, and HOMA-IR, which contrasted with changes in 1-h and 2-h post-load venous plasma glucose values. Interestingly, umbilical cord C-peptide and glucose displayed similar trends to that of the fasting plasma glucose. While overall prevalence of GDM did not vary significantly by seasons, this study illustrates that seasonality is indeed an additional factor when interpreting OGTT results for the diagnosis of GDM and provides new direction for future research into the seasonal adjustment of OGTT results.

SAT-124 Hyperglycemia and Adverse Pregnancy Outcome Follow-Up Study (HAPO FUS): Newborn Anthropometrics and Childhood Glucose Metabolism

The prevalence of insulin resistance and type 2 diabetes (T2DM) in children is increasing, and identifying where prevention can best be implemented is an emerging area of research. The association of low birth weight with long-term risk for poor metabolic health is well established, but the association of newborn size at birth, including adiposity, with measures of glucose metabolism in children has not been fully elucidated. To address this, we used longitudinal data from the international, multi-ethnic Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and HAPO Follow Up Study (FUS). Newborn birth weight (BW) and sum of skinfolds (SSF), as a measure of adiposity, collected during HAPO, together with glucose and C-peptide levels collected during an oral glucose tolerance test (OGTT) in 4160 HAPO FUS offspring at age 10-14 years were examined. Multiple logistic and linear regression were used for statistical analyses to examine associations between primary predictors, BW and SSF, with child metabolic outcomes. Covariate adjustments included HAPO field center, child age, sex, Tanner stage, maternal variables at pregnancy OGTT (age, height, mean arterial pressure, parity (0, 1+), smoking (yes/no), drinking alcohol (yes/no), gestational age), child’s family history of diabetes in first degree relatives and child’s BMI z-score. BW was inversely associated with the 30-min, 1-h, and 2-h plasma glucose levels (Beta=-1.59, CI: -2.53 - -0.65, p<0.0001, Beta=-2.09, CI: -3.30 - -0.88, p=0.007, and Beta=-1.47, CI: -2.28- -0.65, p=0.0004, respectively for BW higher by 1 standard deviation), as was SSF (Beta= -1.40, CI: -2.19 - -0.60, p< 0.0001, Beta=-1.97, CI: -3.00 - -0.94, p=0.0002, and Beta=-0.98, CI: -1.67 - -0.28, p=0.01 respectively for SSF higher by 1 standard deviation). BW and SSF were also associated with a higher Matsuda index, a measure of insulin sensitivity (Beta=1.77, CI: 1.32-2.21, p<0.0001 and Beta=0.89, CI: 0.50-1.27 p<0.0001, respectively). However, only SSF had a positive association with the disposition index, a measure of beta cell compensation for insulin resistance (Beta=0.03, CI: 0.01-0.05, p=0.01). No association was found between BW and SSF and impaired glucose tolerance, while a modest decrease in risk for impaired fasting glucose was seen with higher BW and SSF (OR=-0.83, CI: 0.70-0.98, p=0.03 and OR=0.85, CI: 0.74-0.97, p=0.02, respectively). This study demonstrates that higher BW and newborn adiposity are associated with lower glucose levels and higher insulin sensitivity in childhood. This suggests a complex relationship between birth size and long-term metabolic health in which, after adjusting for child BMI, higher BW and adiposity are associated with better metabolic health during childhood.

Efficacy of oral glucose tolerance testing of pregnant women post bariatric surgery

Worldwide, a large proportion of childbearing women are overweight or obese, and it is becoming increasingly common for pregnant women to have undergone bariatric surgery before conceiving. Women with a history of sleeve gastrectomy may not be able to undertake the oral glucose tolerance test, due to the risk of dumping syndrome. There is limited research on the effects of weight loss surgery on the pregnancy oral glucose tolerance test and conducting this test on a woman who has had bariatric surgery may be an inadequate form of diagnosing gestational diabetes mellitus. A cost-effective alternative to an oral glucose tolerance test is to monitor pre-and post-meal blood glucose levels.

Factors predicting early postpartum glucose intolerance in Japanese women with gestational diabetes mellitus: decision-curve analysis.

To identify factors predicting early postpartum glucose intolerance in Japanese women with gestational diabetes mellitus, using decision-curve analysis. A retrospective cohort study was performed. The participants were 123 Japanese women with gestational diabetes who underwent 75-g oral glucose tolerance tests at 8-12 weeks after delivery. They were divided into a glucose intolerance and a normal glucose tolerance group based on postpartum oral glucose tolerance test results. Analysis of the pregnancy oral glucose tolerance test results showed predictive factors for postpartum glucose intolerance. We also evaluated the clinical usefulness of the prediction model based on decision-curve analysis. Of 123 women, 78 (63.4%) had normoglycaemia and 45 (36.6%) had glucose intolerance. Multivariable logistic regression analysis showed insulinogenic index/fasting immunoreactive insulin and summation of glucose levels, assessed during pregnancy oral glucose tolerance tests (total glucose), to be independent risk factors for postpartum glucose intolerance. Evaluating the regression models, the best discrimination (area under the curve 0.725) was obtained using the basic model (i.e. age, family history of diabetes, BMI ≥25 kg/m2 and use of insulin during pregnancy) plus insulinogenic index/fasting immunoreactive insulin <1.1. Decision-curve analysis showed that combining insulinogenic index/fasting immunoreactive insulin <1.1 with basic clinical information resulted in superior net benefits for prediction of postpartum glucose intolerance. Insulinogenic index/fasting immunoreactive insulin calculated using oral glucose tolerance test results during pregnancy is potentially useful for predicting early postpartum glucose intolerance in Japanese women with gestational diabetes.

Laboratory diagnosis of gestational diabetes: An in silico investigation into the effects of pre-analytical processing on the diagnostic sensitivity and specificity of the oral glucose tolerance test

IntroductionDelayed separation of red cells from plasma causes pre analytical glucose loss, which in turn results in an under-diagnosis of GDM (gestational diabetes) based on the OGTT (oral glucose tolerance test). In silico investigations may help laboratory decision making, when exploring pragmatic improvements to sample processing. MethodsLate pregnancy 0, 1 and 2h 75g OGTT values were obtained from two distinct populations of pregnant women: 1. Values derived from the HAPO (Hyperglycemia and Adverse Pregnancy Outcome) Study and 2. New Zealand women identified as at higher risk of GDM by their caregivers, undergoing OGTT during routine antenatal care. In both populations studied, in silico modelling focussed on the effects of pre-analytical delays in plasma separation, when using fluoride collection tubes. ResultsUsing a model that ‘batched’ samples from the three OGTT collection times, diagnostic sensitivity was estimated as follows: 66.1% for HAPO research population and 48.4% for the 1305 women receiving routine antenatal care. If samples were not batched, but processed shortly after each blood sample was collected, then sensitivity increased to 81%. ConclusionExploration of a range of clinical and laboratory scenarios using in silico modelling, showed that delaying the processing of pregnancy OGTT samples, using batched sample collection into fluoride tubes, causes unacceptable loss of GDM diagnostic sensitivity across two distinct population groups. This modelling approach will hopefully provide information that helps with final decision making around improved laboratory processing techniques.