Computerized analysis of fetal heart rate indices during oral glucose tolerance test

AIMS: To study the effect of maternal glucose ingestion during a 100 g oral glucose tolerance test on fetal heart rate indices. STUDY DESIGN: Prospective study including 50 pregnant patients with an abnormal glucose challenge test who underwent a 100 g glucose tolerance test at 26-28 weeks gestation. Fetal heart rate was recorded and analyzed with the computerized Sonicaid Fetal Monitor System (Oxford 8000). RESULTS: Baseline fetal heart rate significantly increased 120 and 180 minutes following glucose ingestion (p < 0.05) both in patients who were subsequently diagnosed to have gestational diabetes and in these in whom the diagnosis was excluded. No significant changes were noted in other fetal heart indices. CONCLUSIONS: The significant and consistent increase in baseline fetal heart rate following maternal glucose ingestion indicates that the fetus responds to changes in its' environment. The exact mechanism which causes this response has yet to be defined.