The potential for dietary intervention postpartum in women with gestational diabetes

Postpartum glucose follow-up and lifestyle management after gestational diabetes mellitus: general practitioner and patient perspectives

Background

Incidence of type 2 diabetes is high after gestational diabetes mellitus (GDM). We aimed to evaluate the adherence to follow-up six-weeks postpartum visits in secondary care after GDM and glucose monitoring in primary care longer than 12–14 months after delivery and the years thereafter. In addition, we examined the women’s lifestyle after delivery.

Methods

A cross-sectional follow-up survey among women with a history of GDM and their general practitioners (GP). Rates of attendance at the six-weeks postpartum visit and glucose testing were obtained from hospital records, over the period 2011–2012. Rates of annual follow-up postpartum glucose testing were assessed by a survey among their GP’s. Lifestyle of the women on diet and exercise was assessed by questionnaire in 2015.

Results

In total 197 women were eligible for the study. Of these, 156 (79%) attended the six-weeks postpartum visit at the diabetes outpatient clinic and in 145 (93%) of these women glucose testing was performed. In total 77 (39%) women responded to the invitation to participate in this study and filled in the lifestyle questionnaire. About one third of the women met the recommendations for sufficient physical activity. A majority of them did not fulfil the Dutch guidelines on healthy diet – fruit intake 35.1%, vegetables intake 7.8%. Of the 74 invited GP’s, 61 responded (82%), only 12 (20%) reported that they had performed a follow-up glucose testing within >12–14 months postpartum. Of these women, five were tested only in the first year of follow-up, five also in the second year, and two were tested for three consecutive years.

Conclusions

Despite the high attendance rate of six-weeks postpartum visit and glucose testing, we observed low rates of longer-term follow-up regarding postpartum glucose testing. Moreover, we found a suboptimal adherence to healthy lifestyle for women with a history of GDM.

Advice that includes food sources of unsaturated fat supports future risk management of gestational diabetes mellitus

Abstract Women with gestational diabetes mellitus (GDM) have a greater risk of developing type 2 diabetes mellitus (DM) and heart disease than pregnant women without GDM. Advice given during the GDM pregnancy provides an opportunity to develop protective dietary patterns for the long-term management of this risk. Dietary guidelines for the prevention and management of type 2 DM support the inclusion of unsaturated fats, but food advice needs to target this outcome. The aim of this study was to compare the dietary intakes of women with GDM given general low-fat advice (control group) to women with GDM given the same advice with additional targets for food sources of unsaturated fats (intervention group). After approximately 6 weeks, the intervention group reported more ideal dietary fatty acid intakes than the control group, with polyunsaturated:saturated fat ratios of 1:1 and 0.4:1, respectively ( P < .001), assessed using repeated measures analysis of variance. These results confirm the need to include food sources of unsaturated fats in advice strategies to assure optimal protective eating habits in this at-risk group.

Effect of macronutrient intake on the development of glucose intolerance during pregnancy

BACKGROUND

Dietary intake influences glucose tolerance status, yet the relation between macronutrient intake and the development of glucose intolerance during pregnancy has not been adequately examined.

OBJECTIVE

We examined the relation between macronutrient intake early in pregnancy and the development of glucose intolerance.

DESIGN

Data are from 1698 women in the Pregnancy, Infection, and Nutrition Study. Dietary intake during the second trimester was assessed with a food-frequency questionnaire. Women were classified into 1 of 3 glucose categories: gestational diabetes mellitus (GDM), impaired glucose tolerance (IGT), and normal glucose tolerance. Multivariate logistic regression was used to calculate the relative risk of IGT and GDM, with adjustment for potential confounders. A series of models were specified to test alternate hypotheses about the relation of diet to risk of IGT or GDM.

RESULTS

The overall prevalences of IGT and GDM in the cohort were 2.6% and 5.2%, respectively. The addition model showed that adding 100 kcal from carbohydrates to the diet was associated with a 12% decrease in risk of IGT and a 9% decrease in risk of GDM. The substitution model showed that substituting fat for carbohydrates (per each 1% of total calories) resulted in a significant increase in risk of both IGT and GDM [relative risk = 1.1 (95% CI: 1.02, 1.12) and 1.1 (1.02, 1.10), respectively]. Predicted probabilities of IGT and GDM were reduced by one-half with a 10% decrease in dietary fat and a 10% increase in carbohydrate.

CONCLUSIONS

This study found an association between increased fat intake and the development of glucose abnormalities in pregnancy.

Lifestyle change after gestational diabetes

AIMS

Gestational diabetes mellitus (GDM) is a predictor for overt diabetes later in life. Thus, during pregnancy GDM patients are instructed to change lifestyle after pregnancy. The purpose of the present study was to assess the lifestyle changes made by these women.

METHODS

The study was a mailed survey with structured questions on diet, weight loss, exercise and worry about developing diabetes. One hundred and twenty-one (79%) women agreed to participate 11-42 months after pregnancy. Weight gain or loss was defined as a change >/=5 kg.

RESULTS

Among women with body mass index (BMI) >25 kg/m(2), only 18% lost weight and more than 33% gained weight. In total, more women gained than lost weight (P<0.05). Prior to pregnancy, 90 (74%) women followed a diet rich in fat. In contrast, only 57 women (47%) did so at follow-up (P<0.001). Further analysis showed that among these 57 women, only 7% had lost weight since pregnancy compared to 25% of women eating healthy (P<0.05). Eighty-six percent were worried to some extent about the risk for subsequent diabetes. The exercise level did not change after pregnancy. Nineteen women (16%) had overt diabetes mellitus and 22 (18%) impaired glucose tolerance (IGT) at follow-up.

CONCLUSIONS

Although the majority of the women were concerned about developing overt diabetes, only a few had changed their lifestyle and/or lost weight after pregnancy. This indicates that lifestyle instruction needs to be much more frequent and intensive in the period after pregnancy in these women.

The implementation of nutritional advice for people with diabetes

These consensus-based recommendations emphasize the practical implementation of nutritional advice for people with diabetes, and describe the provision of services required to provide the information. Important changes from previous recommendations include greater flexibility in the proportions of energy derived from carbohydrate and monounsaturated fat, further liberalization in the consumption of sucrose, more active promotion of foods with a low glycaemic index, and greater emphasis on the provision of nutritional advice in the context of wider lifestyle changes, particularly physical activity. Monounsaturated fats are now promoted as the main source of dietary fat because of their lower susceptibility to lipid peroxidation and consequent lower atherogenic potential. Consumption of sucrose for patients who are not overweight can be increased up to 10% of daily energy provided that this is eaten in the context of a healthy diet and distributed throughout the day [corrected]. Evidence is presented for the effectiveness of advice provided by trained dieticians. The increasing evidence for the importance of good metabolic control and the growing requirement for measures to prevent Type 2 diabetes in an increasingly obese population will require major expansion of dietetic services if the standards in National Service Frameworks are to be successfully implemented.

The principles of dietary management of gestational diabetes: reflection on current evidence

BACKGROUND

Gestational diabetes (GDM) is the commonest metabolic disorder of pregnancy. Most women with GDM are treated with nutritional management alone. There are conflicting guidelines surrounding its dietary management and this has resulted in a lack of conformity to the dietary advice currently prescribed. There is also conflicting opinions to the effectiveness of dietary management of GDM on pregnancy outcomes. The aim of this review was to examine the scientific evidence for the optimal nutritional management of GDM.

METHODS

A Medline search of all English papers published between 1995 and 2001 that cross-referenced GDM with diet was under taken. Because of the poor quality of many of these papers, literature prior to 1995 known to the authors and considered relevant to the review were also included.

RESULTS

The evidence base in this area is of poor quality. One systematic review based on randomized control trials failed to show any benefit from dietary intervention in GDM. However, that review did not include informative clinical and observational studies that are not classified as randomized controlled trials. Overall current evidence points to the effectiveness of dietary advice as a means of improving maternal hyperglycaemia and reducing the risk of accelerated foetal growth. The evidence surrounding energy restriction, carbohydrate and fat manipulation in GDM remains controversial.

CONCLUSIONS

Current but limited evidence supports dietary alterations to reduce rates of accelerated foetal growth. There is a clear need for good quality randomized control trials in this area.

Diabetes complicating pregnancy

Despite the well-documented relationship between morbidity in pregnancy and pregestational maternal diabetes, the corrected perinatal outcome is, in most series, equal to or better than that of the general reference obstetric population. No single aspect or element of contemporary management is responsible for this improvement; rather, a combination of interventions seems responsible. Targeting delivery early in term, improved compliance, better glycemic control during pregnancy, improved control at conception, improved neonatal care, family planning, and early screening for fetal abnormalities all likely contribute to improved outcome. The currently observed rates of perinatal mortality suggest that an irreducible minimum mortality rate may be reached; however, large disparities in access to care and treatment continue to result in a wide range in rates of morbidity and mortality, a fact that pertains to outcomes in general as well as to pregnancies complicated by diabetes. The identification of women with lesser degrees of hyperglycemia as diabetic by lowering the thresholds for glucose tolerance test abnormality suggests an importance of the diagnosis that is not supported by evidence of either related morbidity or therapeutic benefit. The extrapolation of risk to women with lesser degrees of hyperglycemia seems to have little basis, and the management of women with mild glucose intolerance as if they had overt diabetes is unwarranted. The excess of resources dedicated to the identification and monitoring of an increasing number of women with mild abnormalities of glucose metabolism should prompt a reevaluation of these practices. Perinatal benefits of this expenditure are difficult to document or nonexistent, and there is a predictable increase in iatrogenic morbidities associated with the diagnosis. The exception in the most recent recommendations is the addition of a random glucose measure to screen for the rare women with overt undiagnosed diabetes who presents for prenatal care, because these women are at increased risk of morbidities related to diabetes. A curious statement was made in the summary and recommendations of the fourth International Congress on Gestational Diabetes: "There remains a compelling need to develop diagnostic criteria for GDM [gestational diabetes mellitus] that are based on the specific relationships between hyperglycemia and risk of adverse outcome." If these relationships are undefined, what is the import of the diagnosis? At the author's center, application of the new diagnostic thresholds for the diagnosis of gestational diabetes mellitus has increased the incidence to over 6%. Without a clear expectation of benefit, this increase represents an unsupportable investment of resources. What are the prospects for improving understanding of the relationships between glucose intolerance and pregnancy risks? The direction of new guidelines and recommendations seems to be moving away from resolution of the relationships. The new criteria result in the diagnosis of gestational diabetes in an increasing number of women who were previously normal. It is easier to differentiate women at an extreme of hyperglycemia from normal. Investigations will be even less able to identify attributable effects of glucose intolerance in pregnancy with the inclusion of women with lesser degrees of hyperglycemia. As evidenced in O'Sullivan's original series, women with fasting hyperglycemia in pregnancy are still presumed to be at increased risk of fetal death. This risk factor remains important in clinical management if insulin treatment, fetal surveillance, and early term delivery can reduce the risk of fetal loss. At the author's center, the relationships among outpatient measures of fasting glycemia, glucose tolerance testing results, and perinatal outcomes are evaluated. Preliminary results suggest that fasting glycemia measured at the time of a 50-g glucose tolerance test is significantly correlated with and as sensitive and predictive of morbidity as the glucose tolerance test diagnosis of gestational diabetes. If these results are confirmed, it will be difficult to rationalize continued glucose tolerance testing.

The relevance of the glycaemic index to our understanding of dietary carbohydrates

AIMS

To review the evidence for the importance of glycaemic index of dietary carbohydrate in disease prevention and control.

METHODS

A critical appraisal of the literature published in English between and cited on Medline between January 1966 and October 1999.

RESULTS

Using basic, intervention and epidemiological studies from experienced teams, evidence that the glycaemic index of diet may influence outcome in terms of cardiovascular risk, risk of metabolic syndrome diseases and pregnancy was found.

CONCLUSIONS

Consideration of glycaemic indices in making dietary recommendations may be expected to produce additional health benefit.