Role of colour Doppler indices in the diagnosis of intrauterine growth retardation in high-risk pregnancies.

PURPOSE

Intra uterine growth retardation (IUGR) due to fetoplacental vascular insufficiency is rampant in developing countries like India. Owing to the lack of awareness, antenatal patients often present in their third trimester for their first ultrasound examination. Alterations in the waveforms and Doppler indices of fetal middle cerebral artery (MCA), umbilical artery and bilateral uterine arteries have been extensively described in various studies in the literature. However, the role of each doppler parameter in actually predicting reduced birth weight (for gestational age) in the third trimester is often debatable and frustrating.

METHOD

A prospective study was done on 100 patients of clinically suspected IUGR/high-risk pregnancies of 31-41 weeks. The cases were followed till delivery; the doppler and grey scale findings were correlated with the birth weight of the baby.

RESULT

The highest sensitivity was found to be of HC/AC ratio, (84.4 %), the highest specificity of oligohydramnios and Cerebral/Umbilical Pulsatility ratio[C/U ratio] (100 %). The sensitivity of C/U ratio was found to be 68.8 %. Fetal MCA had the lowest sensitivity (7.7 %).

CONCLUSION

HC/AC ratio is quite sensitive, and oligohydramnios is a highly specific parameter to diagnose IUGR. However, the former has lower specificity, and the latter has very poor sensitivity. The MCA PI alone is not sensitive at all, and should not be used for screening purposes in IUGR patients. Also, C/U ratio is more sensitive than oligohydramnios and more specific than HC/AC ratio and stands out as the best parameter of all to diagnose IUGR in the third trimester.