Time to reassess the optimal dietary prescription for women with gestational diabetes

The role of gestational diabetes, pre-pregnancy body mass index and gestational weight gain on the risk of newborn macrosomia: results from a prospective multicentre study

BACKGROUND

It is crucial to identify in large population samples the most important determinants of excessive fetal growth. The aim of the study was to evaluate the independent role of pre-pregnancy body mass index (BMI), gestational weight gain and gestational diabetes on the risk of macrosomia.

METHODS

A prospective study collected data on mode of delivery and maternal/neonatal outcomes in eleven Hospitals in Italy. Multiple pregnancies and preterm deliveries were excluded. The sample included 14109 women with complete records. Associations between exposure variables and newborn macrosomia were analyzed using Pearson's chi squared test. Multiple logistic regression models were built to assess the independent association between potential predictors and macrosomia.

RESULTS

Maternal obesity (adjusted OR 1.7, 95% CI 1.4-2.2), excessive gestational weight gain (adjusted OR 1.9, 95% CI 1.6-2.2) and diabetes (adjusted OR 2.1, 95% CI 1.5-3.0 for gestational; adjusted OR 3.0, 95% CI 1.2-7.6 for pre-gestational) resulted to be independent predictors of macrosomia, when adjusted for other recognized risk factors. Since no significant interaction was found between pre-gestational BMI and gestational weight gain, excessive weight gain should be considered an independent risk factor for macrosomia. In the sub-group of women affected by gestational or pre-gestational diabetes, pre-gestational BMI was not significantly associated to macrosomia, while excessive pregnancy weight gain, maternal height and gestational age at delivery were significantly associated. In this sub-population, pregnancy weight gain less than recommended was not significantly associated to a reduction in macrosomia.

CONCLUSIONS

Our findings indicate that maternal obesity, gestational weight gain excess and diabetes should be considered as independent risk factors for newborn macrosomia. To adequately evaluate the clinical evolution of pregnancy all three variables need to be carefully assessed and monitored.

Relationship between caloric intake and pregnancy outcome in diet-treated gestational diabetes mellitus

A prospective observational study was performed to examine the relationship between estimated caloric intake with maternal blood glucose profile and infant outcome in a group of Chinese women with gestational diabetes mellitus (GDM) treated by diet alone. Following the diagnosis of GDM according to the World Health Organization (WHO) criteria, and using a 75 g oral glucose tolerance test (OGTT), 62 non-obese Chinese women who had completed a 5-day dietary survey were recruited into the study. They were categorized by their mean caloric intake over 5 days into tertiles for comparison of gestational weight gain, glycemic control and pregnancy outcome. Subjects in the highest tertile had a mean intake close to the prescribed intake. No differences were seen in maternal characteristics, gestational weight gain, OGTT, other postprandial glucose concentrations, or infant outcome among the tertiles. Our findings indicated that as long as the caloric intake did not exceed that prescribed, the infant outcome remained satisfactory.

Nutrition and pregnancy: the link between dietary intake and diabetes

Pregnancy is a time when serial metabolic changes in the mother are carefully regulated to provide optimum substrate to both mother and fetus. Subtle perturbations in maternal metabolism can have implications not only for the index pregnancy, but also for future generations. The literature provides evidence that maternal nutrition plays a major role in the destiny of the offspring. Both maternal malnutrition and overnutrition are associated with subsequent diabetes in the offspring. Pregnancy represents a window of opportunity for health care providers to change dietary patterns toward habits that will be healthier for the individual now, as well as impacting on the future. The challenge for clinicians is to provide nutritional information based on scientific evidence that facilitates the normalization of fetal nutrition, and thus minimize the risk that the child will develop diabetes.

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.

Higher carbohydrate intake is associated with decreased incidence of newborn macrosomia in women with gestational diabetes

OBJECTIVE

To study the influence of energy and macronutrient intake on infant birthweight in women with gestational diabetes mellitus undergoing intensive management.

DESIGN

This prospective study evaluated the impact of intensive management of gestational diabetes on maternal and fetal morbidity, and addressed the relationship between food intake and infant birthweight.

SETTING

Fifteen maternity hospitals in northern France.

SUBJECTS

Ninety-nine women with gestational diabetes or gestational mild hyperglycemia diagnosed between 24 and 34 weeks of gestation were surveyed. After 1 was excluded because of a premature birth and 18 were excluded as underreporters, 80 women were included in the final analysis. Diet intake was assessed by a dietary history at the first interview, and by two 3-day diet records at the 3rd and 7th week after diagnosis.

RESULTS

In a forward-stepwise regression analysis (controlling for maternal age; smoking; parity; prepregnancy BMI; pregnancy weight gain; gestational duration; infant sex; fasting and 2-hour postprandial serum glucose; insulin therapy; and energy, fat, protein and carbohydrate intake during treatment) infant birthweight was positively associated with gestational duration (beta = +0.34, P<.002), and negatively with smoking (beta = -0.27, P<.02) and carbohydrate intake (beta = -0.24, P<.03). There were no large-for-gestational-age infants among women whose carbohydrate intake exceeded 210 g/day.

CONCLUSION

For women with gestational diabetes undergoing intensive management, higher carbohydrate intake is associated with decreased incidence of macrosomia.

APPLICATION

These findings suggest that nutrition counseling in gestational diabetes must be directed to maintain a sufficient carbohydrate intake (at least 250 g per day), which implies a low-fat diet to limit energy intake. A careful distribution of carbohydrate throughout the day and the use of low-glycemic index foods may help limit postprandial hyperglycemia.