The effect of diet on pregnancy outcomes among pregnant with abnormal glucose challenge test

Gestational diabetes mellitus (GDM) is defined as glucose intolerance, first time detected in pregnancy. Diagnostic criteria for GDM have changed over the decades. The aim of the study was to examine the effect of diet on birth weight, number of large for gestational age (LGA) (birth weight > 90th percentile) babies, total maternal weight gain, gestational age and route of delivery among patients with positive 50 g glucose challenge test (GCT) and negative 100 g oral glucose tolerance test (OGTT).

A prospective randomized controlled study was conducted among patients with positive 50 g GCT and negative 100 g OGTT. A plasma glucose value of 140 mg/dL was used as the threshold to define an abnormal GCT result. In group 1 50 patients were given a caloric diet and compared with group 2 with 50 patients without a given diet. Patients were followed up until delivery and evaluated for birth weight, number of LGA babies, total maternal weight gain, gestational age and route of delivery.

There were no significant differences between the groups in maternal age, parity, body mass index and gestational age at delivery. There were significant differences in birth weight, number of LGA babies, total maternal weight gain during pregnancy. The mean gestational age at delivery was 38.7±1.2 weeks in group 1 and 38.9±1.1 weeks in group 2 (p = 0.615). The mean birth weight in group 1 was 3328±399 g and 3623±485 g in group 2 (p = 0.007), cesarean rate was 32% in group 1 and 40% in group 2 (p = 0.405).

In the management of patients with positive 50 g GCT and negative 100 g OGTT, patients who were prescribed medical nutrition therapy by a dietitian experienced in GDM management had better perinatal outcomes.