Medical nutrition therapy for gestational diabetes mellitus in Australia: What has changed in 10 years and how does current practice compare with best practice?

BACKGROUND: The present study aimed to report Australian dietetic practice regarding management of gestational diabetes mellitus (GDM) and to make comparisons with the findings from a 2009 survey of dietitians and with the Academy of Nutrition and Dietetics Evidence-Based Nutrition Practice Guidelines (NPG). METHODS: Cross-sectional surveys were conducted in 2019 and 2009 of dietitians providing medical nutrition therapy (MNT) to women with GDM in Australia. The present study compares responses on demographics, dietetic assessment and interventions, and guideline use in 2019 vs. 2009. RESULTS: In total, 149 dietitians (2019) and 220 (2009) met survey inclusion criteria. In both surveys >60% of respondents reported dietary interventions aiming for >45% energy from carbohydrate, 15%-25% energy from protein and 15%-30% energy from fat. Many variations in MNT found in 2009 continued to be evident in 2019, including the percentage of energy from carbohydrate aimed for (30%-65% in 2019 vs. 20%-75% in 2009) and the wide range in the recommended minimum daily carbohydrate intake (40-220 and 60-300 g). Few dietitians reported aiming for the NPG minimum of 175 g of carbohydrate daily in both surveys (32% in 2019 vs. 26% in 2009). There were, however, some significant increases in MNT consistent with NPG recommendations in 2019 vs. 2009, including the minimum frequency of visits provided (49%, n = 61 vs. 33%, n = 69; p < 0.001) and provision of gestational weight gain advice (59%, n = 95 vs. 40%, n = 195; p < 0.05). CONCLUSIONS: Although many dietitians continue to provide MNT consistent with existing NPG, there is a need to support greater uptake, especially for recommendations regarding carbohydrate intake.

Does weight management after gestational diabetes mellitus diagnosis improve pregnancy outcomes? A multi-ethnic cohort study.

AIMS: To assess the impact of achieving an Institute of Medicine based personalised weight target in addition to conventional glycaemic management after gestational diabetes mellitus diagnosis on maternal and neonatal outcomes. METHODS: A retrospective audit of clinical data (2016-2019) for singleton gestational diabetes pregnancies was conducted in a multi-ethnic cohort. Logistic regression analyses assessed relationships between achieving, exceeding and gaining less than a personalised weight target provided after gestational diabetes diagnosis and rates of large for gestational age, small for gestational age infants, insulin therapy initiation and neonatal outcomes. Adjusted odds ratios (aOR) were adjusted for glucose 2-h post-glucose load value, family history of type 2 diabetes, previous gestational diabetes, macrosomia in a previous pregnancy, and East and South-East Asian ethnicity. RESULTS: Of 1034 women, 44% (n = 449) achieved their personalised weight target. Women who exceeded their personalised weight target had significantly and higher mean insulin doses (28.8 ± 21.5 units vs. 22.7 ± 18.7, p = 0.006) and higher rates of large for gestational age infants (19% vs. 9.8%, p < 0.001), with aOR of 1.99 [95% CI 1.25-3.15] p = 0.004, but no difference in rates of small for gestational age infants (5.3% vs. 8.0%) (aOR 0.77 [0.41-1.44] p = 0.41). Lower rates of large for gestational age infants occurred in those who gained below their personalised weight target (aOR 0.48 [0.25-0.95] p = 0.034), but rates of small for gestational age infants concurrently increased (aOR 1.9 [1.19-3.12] p = 0.008). CONCLUSIONS: Weight management after gestational diabetes diagnosis does not appear to be too late to confer additional benefits to glucose-lowering treatment, resulting in lower mean insulin doses, and lower rates of large for gestational age infants without increasing the risk of small for gestational age infants.

Excessive Weight Gain Before and During Gestational Diabetes Mellitus Management: What Is the Impact?

OBJECTIVE: Conventional gestational diabetes mellitus (GDM) management focuses on managing blood glucose in order to prevent adverse outcomes. We hypothesized that excessive weight gain at first presentation with GDM (excessive gestational weight gain [EGWG]) and continued EGWG (cEGWG) after commencing GDM management would increase the risk of adverse outcomes, despite treatment to optimize glycemia. RESEARCH DESIGN AND METHODS: Data collected prospectively from pregnant women with GDM at a single institution were analyzed. GDM was diagnosed on the basis of Australasian Diabetes in Pregnancy Society 1998 guidelines (1992-2015). EGWG means having exceeded the upper limit of the Institute of Medicine-recommended target ranges for the entire pregnancy, by GDM presentation. The relationship between EGWG and antenatal 75-g oral glucose tolerance test (oGTT) values and adverse outcomes was evaluated. Relationships were examined between cEGWG, insulin requirements, and large-for-gestational-age (LGA) infants. RESULTS: Of 3,281 pregnant women, 776 (23.6%) had EGWG. Women with EGWG had higher mean fasting plasma glucose (FPG) on oGTT (5.2 mmol/L [95% CI 5.1-5.3] vs. 5.0 mmol/L [95% CI 4.9-5.0]; P < 0.01), after adjusting for confounders, and more often received insulin therapy (47.0% vs. 33.6%; P < 0.0001), with an adjusted odds ratio (aOR) of 1.4 (95% CI 1.1-1.7; P < 0.01). aORs for each 2-kg increment of cEGWG were a 1.3-fold higher use of insulin therapy (95% CI 1.1-1.5; P < 0.001), an 8-unit increase in final daily insulin dose (95% CI 5.4-11.0; P < 0.0001), and a 1.4-fold increase in the rate of delivery of LGA infants (95% CI 1.2-1.7; P < 0.0001). CONCLUSIONS: The absence of EGWG and restricting cEGWG in GDM have a mitigating effect on oGTT-based FPG, the risk of having an LGA infant, and insulin requirements.

Initial group dietary education compared to individual education in gestational diabetes mellitus management: Do outcomes differ?

AIMS: To assess the effectiveness of Initial Group versus Initial Individual GDM dietary education in terms of insulin requirements and pregnancy outcomes. METHODS: A retrospective audit of clinical data was conducted where English speaking women who received initial education in a group setting (01-2-2012 to 01-2-2014) (Group), were compared to women who received initial individual education with a dietitian (1-2-2010 to 31-1-2012) (Individual), all followed by one individual dietitian appointment. The same dietary information was provided in both settings. Data collected included: attendance rates, insulin requirements, maternal weight gain, and rates of adverse birth outcomes. Data were compared by t-test or Chi-squared test. Multivariable logistic regression analysis was conducted to determine independent predictors of insulin therapy. RESULTS: Of 743 women; (362 Group and 381 Individual), Group women had a lower HbA1c at GDM diagnosis 5.3 ±â€¯0.6% versus 5.5 ±â€¯0.5% (34 ±â€¯6.6 mmol/mol versus 37 ±â€¯5.5 mmol/mol p < 0.0001). There were no other differences in baseline characteristics. More Group women required insulin (42.0% versus 34.6%, p = 0.048). Group education was found to be an independent predictor of insulin therapy (OR = 1.9 [1.29, 2.75] p < 0.001). CONCLUSIONS: Despite adjusting for all known potential confounders, unlike Individual education, Group education remained a significant predictor of insulin therapy (but resulted in similar therapeutic and pregnancy outcomes to Individual education).

Are the Institute of Medicine weight gain targets applicable in women with gestational diabetes mellitus?

AIMS/HYPOTHESIS: Our aim was to study the relationship between excessive gestational weight gain (GWG) according to Institute of Medicine (IOM) targets and perinatal outcomes, and examine whether modifying targets may improve outcomes in women with gestational diabetes mellitus (GDM). METHODS: This was a retrospective cohort study of all GDM pregnancies from 1992 to 2013. ORs were calculated for associations between excessive GWG (EGWG) using IOM targets and adverse pregnancy outcomes. ORs were then adjusted for maternal age, gestational age at diagnosis, prepregnancy BMI, gravidity, parity, ethnicity, antenatal fasting blood glucose level (BGL), 2 h BGL and HbA1c. BMI was categorised into underweight (<18.5 kg/m2), healthy weight (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2) and obese (≥30 kg/m2). Large for gestational age (LGA) was defined as birthweight above the 90th percentile, small for gestational age (SGA) was birthweight below the 10th percentile, macrosomia was birthweight >4000 g, and preterm delivery was delivery prior to 37 weeks' gestation. Modified GWG targets were derived by: (1) subtracting 2 kg from the upper IOM target only; (2) subtracting 2 kg from both upper and lower targets; (3) using the interquartile range of maternal GWG of women with infants who were appropriate for gestational age per BMI category; and (4) restricting GWG to 0-4 kg in women with BMI ≥35 kg/m2. RESULTS: Among 3095 GDM pregnancies, only 31.7% had GWG within IOM guidelines. Adjusted ORs for women who exceeded GWG were Caesarean section (1.5; 95% CI 1.2, 1.9), LGA (1.8; 95% CI 1.4, 2.4) and macrosomia (2.3; 95% CI 1.6, 3.3); there was a lower risk of SGA (adjusted OR 0.5; 95% CI 0.3, 0.7). CONCLUSIONS/INTERPRETATION: EGWG according to IOM targets was associated with Caesarean section, LGA and macrosomia. Modification of IOM criteria, including more restrictive targets, did not improve perinatal outcomes.

A novel validated model for the prediction of insulin therapy initiation and adverse perinatal outcomes in women with gestational diabetes mellitus.

AIMS/HYPOTHESIS: Identifying women with gestational diabetes mellitus who are more likely to require insulin therapy vs medical nutrition therapy (MNT) alone would allow risk stratification and early triage to be incorporated into risk-based models of care. The aim of this study was to develop and validate a model to predict therapy type (MNT or MNT plus insulin [MNT+I]) for women with gestational diabetes mellitus (GDM). METHODS: Analysis was performed of de-identified prospectively collected data (1992-2015) from women diagnosed with GDM by criteria in place since 1991 and formally adopted and promulgated as part of the more detailed 1998 Australasian Diabetes in Pregnancy Society management guidelines. Clinically relevant variables predictive of insulin therapy by univariate analysis were dichotomised and included in a multivariable regression model. The model was tested in a separate clinic population. RESULTS: In 3317 women, seven dichotomised significant independent predictors of insulin therapy were maternal age >30 years, family history of diabetes, pre-pregnancy obesity (BMI ≥30 kg/m(2)), prior GDM, early diagnosis of GDM (<24 weeks gestation), fasting venous blood glucose level (≥5.3 mmol/l) and HbA1c at GDM diagnosis ≥5.5% (≥37 mmol/mol). The requirement for MNT+I could be estimated according to the number of predictors present: 85.7-93.1% of women with 6-7 predictors required MNT+I compared with 9.3-14.7% of women with 0-1 predictors. This model predicted the likelihood of several adverse outcomes, including Caesarean delivery, early delivery, large for gestational age and an abnormal postpartum OGTT. The model was validated in a separate clinic population. CONCLUSIONS/INTERPRETATION: This validated model has been shown to predict therapy type and the likelihood of several adverse perinatal outcomes in women with GDM.