The Carbohydrate Threshold in Pregnancy and Gestational Diabetes: How Low Can We Go?

Abstract

The original nutrition approach for the treatment of gestational diabetes mellitus (GDM) was to reduce total carbohydrate intake to 33–40% of total energy (EI) to decrease fetal overgrowth. Conversely, accumulating evidence suggests that higher carbohydrate intakes (60–70% EI, higher quality carbohydrates with low glycemic index/low added sugars) can control maternal glycemia. The Institute of Medicine (IOM) recommends ≥175 g/d of carbohydrate intake during pregnancy; however, many women are consuming lower carbohydrate (LC) diets (<175 g/d of carbohydrate or <40% of EI) within pregnancy and the periconceptual period aiming to improve glycemic control and pregnancy outcomes. This report systematically evaluates recent data (2018–2020) to identify the LC threshold in pregnancy in relation to safety considerations. Evidence from 11 reports suggests an optimal carbohydrate range of 47–70% EI supports normal fetal growth; higher than the conventionally recognized LC threshold. However, inadequate total maternal EI, which independently slows fetal growth was a frequent confounder across studies. Effects of a carbohydrate intake <175 g/d on maternal ketonemia and plasma triglyceride/free fatty acid concentrations remain unclear. A recent randomized controlled trial (RCT) suggests a higher risk for micronutrient deficiency with carbohydrate intake ≤165 g/d in GDM. Well-controlled prospective RCTs comparing LC (<165 g/d) and higher carbohydrate energy-balanced diets in pregnant women are clearly overdue.

Impact of maternal dietary carbohydrate intake and vitamin D-related genetic risk score on birth length: the Vitamin D Pregnant Mother (VDPM) cohort study

“…The nutritional status of pregnant mothers is an important determinant in maintaining maternal health, such as preventing intrauterine growth restriction and neonatal size [ 51 ]. During pregnancy, vitamin D has been shown to be crucial for the development of the foetal skeletal system, immune system and tooth formation, along with the general growth of the foetus [ 21 ].…”

Fetal programming in diabetes: an emphasis on prevention consequences of ketoacidosis

“…Ц укровий діабет (ЦД) обох типів здійснює несприятливий вплив на перебіг вагітності та погіршує наслідки для матері та плода [1]. Це зумовлено патологічними змінами системного характеру, що виникають як у разі маніфестації хвороби ще до настання вагітності, так і за наявності гестаційного ЦД.…”

“…Одним з важливих завдань є забезпечення обмеження вживання вуглеводів. При цьому вплив харчового режиму з отриманням менше 175 г вуглеводів на день на рівень материнських кетонових тіл і концентрацію тригліцеридів та вільних жирних кислот залишається не з'язованим [23].…”

Effect of Carbohydrate-Restricted Dietary Pattern on Insulin Treatment Rate, Lipid Metabolism and Nutritional Status in Pregnant Women with Gestational Diabetes in Beijing, China

“…The CRD pattern used in the present study included a restricted whole-day CHO intake and a limit of CHO intake at each meal. Evidence based on most studies demonstrates that CRD pattern plays a significant role in the management of GDM, which may improve maternal glycemia and pregnancy outcomes, but the results remain controversial mainly because of the varying degrees of CHO restriction [15,16]. A less restrictive nutritional approach may lead to similar and potentially more favorable outcomes and relieve the anxiety caused by the diagnosis and treatment of the disease [16,17].…”