Effect of macronutrient intake during the second trimester on glucose metabolism later in pregnancy

BACKGROUND: Dietary intake is known to influence glucose metabolism, but there is little consensus on the optimal distribution of macronutrient intakes during pregnancy to prevent gestational diabetes (GDM).

OBJECTIVE: We aimed to investigate whether macronutrient intake distribution during the second trimester of pregnancy was associated with glucose metabolism later in pregnancy.

DESIGN: Women with singleton pregnancies and without preexisting type 1 or type 2 diabetes were included. Participants underwent a 3-h oral-glucose-tolerance test at 30 wk (95% CI: 25, 33 wk) gestation and were asked to recall their second-trimester dietary intake by using a validated food-frequency questionnaire.

RESULTS: Of the 205 participants, 47 (22.9%) had a diagnosis of GDM. A higher intake of saturated fat (β ± SEE: 0.059 ± 0.021; P = 0.005) and trans fat (0.381 ± 0.145; P = 0.009) as a percentage of energy and of added sugar (0.017 ± 0.007; P = 0.02) and a lower intake of vegetable and fruit fiber (-0.026 ± 0.012; P = 0.03) were individually associated with increased fasting glucose after multiple adjustment. In participants with a family history of type 2 diabetes, a higher vegetable and fruit fiber intake was associated with reduced insulin resistance (-0.100 ± 0.029; P = 0.0008) and increased insulin sensitivity (0.029 ± 0.012; P = 0.01), after similar adjustment. An increased risk (OR per 1-SD change) of GDM was associated with lower carbohydrate (0.60; 95% CI: 0.40, 0.90) and higher total fat (1.61; 95% CI: 1.06, 2.44) intakes as a percentage of energy, after similar adjustment.

CONCLUSIONS: Macronutrient intake during the second trimester of pregnancy was associated with a risk of abnormal glucose metabolism later in pregnancy. This finding supports the need for continued work to determine optimal prenatal nutritional strategies to prevent GDM.