Relation of fetal growth to maternal responses to oral glucose tolerance test throughout gestation

Abstract

Fetal growth is dependent on transplacental supply of fuels. We aimed to assess the effect of serial changes in maternal glucose tolerance and insulin secretion with advancing pregnancy on maternal-fetal outcomes. Sixty-nine healthy pregnant women were studied over the course of gestation for glucose tolerance, by oral glucose tolerance test (OGTT), and hemoglobin A(1c) (HbA(1c)), fetal intrauterine growth (by ultrasound) and pregnancy outcome. Seven women had an abnormal OGTT in the third trimester developing gestational diabetes mellitus (GDM), but none of the 12 mothers of large babies (> 3.9 kg) had GDM: the former had the highest post-load glycemic increment, despite an apparently 'normal' insulin secretory response, the latter showed the lowest post-load glucose increase in the face of the lowest insulinemic response. Neonatal body weight correlated with maternal gestational weight gain, placental weight, third trimester ratio of incremental plasma insulin and glucose integrated areas under the curve and first and second trimester HbA(1c) levels. Fetal growth indices (femur length, biparietal diameter and abdominal circumference) were correlated with both HbA(1c) and 2h OGTT. Fetal growth rate is confirmed as being associated with maternal glycemic equilibrium, but one of the main determinants of high infant birthweight seems to be an enhanced maternal insulin sensitivity, accompanied by remarkable gestational weight gain.

The Impact of Maternal Glycemia and Obesity on Early Postnatal Growth in a Nondiabetic Caucasian Population

“…In keeping with other studies (15)(16)(17)(18), we demonstrated maternal glycemia within the normal range was correlated with parameters of fetal growth at birth, including weight, length, and BMI. This effect is most pronounced in the mothers in the upper tertile of glycemic values, suggesting the macrosomia seen in pregnancies complicated by type 2, or gestational, diabetes may be a continuum of the effect of "normal" glucose on birth weight in the nondiabetic pregnancy.…”

“…Insulin-mediated growth of the fetus reflects maternal glycemia, with birth weight being increased in diabetic pregnancies, and correlates with maternal glycemia, in both fasting and stimulated levels, in the nondiabetic pregnancy (15)(16)(17)(18). The impact of glycemia within the normal range on early postnatal growth in European Caucasians is uncertain.…”

The impact on pregnancy outcomes of late‐onset gestational diabetes mellitus diagnosed during the third trimester: A systematic review and meta‐analysis

“…Some studies have reported that additional testing for GDM in the third trimester may diagnose late GDM that developed de novo, following a negative second-trimester screening. 7,8 However, the evidence is inconsistent regarding the impact of such late GDM diagnosis on perinatal outcomes. Although some studies have described similar outcomes in women with late GDM and controls, others have reported increased risks of macrosomia 9 and cesarean delivery 10 in late GDM pregnancies.…”

“…This period has been established as optimal for screening because of the increase in insulin resistance in the second trimester. Some studies have reported that additional testing for GDM in the third trimester may diagnose late GDM that developed de novo, following a negative second‐trimester screening 7,8 . However, the evidence is inconsistent regarding the impact of such late GDM diagnosis on perinatal outcomes.…”