Diagnosis of intrauterine fetal growth retardation (IUGR) and placental insufficiency by a dehydroepiandrosterone sulfate (DHAS) loading test

Abstract

Chronic placental insufficiency results in intrauterine fetal growth retardation (IUGR). The IUGR can be diagnosed by clinical signs (follow-up of maternal weight, fundus height, abdominal circumference), ultrasound examination (biparietal and thoracic diameters, circumferences of the head and the trunk), and by endocrinologic tests (estrogen determination in serum and urine without and after performance of a DHAS loading test). The different ways of performing the DHAS loading test reported in the literature are reviewed. The DHAS loading test measures the aromatization capacity of the human placenta and indirectly its metabolic exchange capacities. After DHAS loading, estrogens (estrone, estradiol, estriol), DHAS and DHA can be determined in blood and urine; furthermore, changes in urine total estrogen excretion can be evaluated. In conclusion, the best parameter for diagnosing IUGR seems to be the determination of the DHAS half-life after DHAS loading. A prolongation of DHAS half-life (greater than 4.7 h) after DHAS loading (50 mg i.v.) is a good index of IUGR.