Second-trimester uterine artery flow velocity waveform and oral glucose tolerance test as a means of predicting intrauterine growth retardation

Abstract

The absence of a rise in maternal serum glucose level during the course of a 3-h glucose tolerance test was noted in pregnancies that resulted in growth-retarded infants. It was postulated that this response to an oral glucose load, in association with increased impedence to uterine artery blood flow, as demonstrated by color flow Doppler waveforms, could select the pregnancies at greater risk of developing intrauterine growth retardation. One hundred and four uncomplicated primigravidae and 88 multigravid women considered to be at high risk of developing intrauterine growth retardation were monitored longitudinally from the 24th week of gestation. The right and left uterine artery resistance indices (RI) were measured at 24 weeks by means of pulsed Doppler with color flow imaging, and the results were averaged. The following week, an oral glucose tolerance test (OGTT) was performed. Serum glucose was measured immediately prior to the ingestion of 100 g glucose, and again after 60, 120 and 180 min. The OGTT results were classified as normal, impaired glucose tolerance, gestational diabetes mellitus, and flat. This last result was indicated by a less than 20% rise in serum glucose compared to the fasting value.A notch in the uterine artery waveform and/or an RI greater than 0.58 (> 2 SD above the mean) was found in 39 (20.3%) women. A flat response to the OGTT was seen in 31 (16.1%) cases. Of the 16 women in whom both a high RI and a flat OGTT response curve were demonstrated, 15 (93.7%) delivered low-birth-weight babies due to intrauterine growth retardation. Eight of these 16 women developed hypertension. In the group with a flat OGTT response curve but normal uterine artery RI, two of the 15 women (13.3%) had growth-retarded babies. The positive predictive value of an increased RI with a flat OGTT response curve was 94%, while the predictive values of each individual method were 62% and 55%, respectively, for development of intrauterine growth retardation.Increased resistance to blood flow in the uteroplacental circulation in conjunction with a flat response curve to an oral glucose load might identify a group of pregnant women at risk of having a growth-retarded infant with or without the development of hypertension.