Human fetoplacental and fetal liver blood flow after maternal glucose loading: a cross-sectional observational study

Abstract

Objective: To study umbilical vein and fetal liver blood flow related to fetal anthropometric measures following maternal oral glucose loading.

Design: Experimental design in a cross-sectional observational study.

Setting: University hospital.

Population: A total of 113 low-risk pregnancies (30-32 weeks of gestation).

Methods: Ultrasound Doppler measurements of umbilical vein and ductus venosus blood flow (ml/min) before and 2 h after completed 75-g oral glucose tolerance test (OGTT). Liver blood flow was defined as the umbilical vein blood flow minus ductus venosus blood flow.

Main outcome measures: Changes in umbilical vein and fetal liver blood flow following OGTT related to fetal biometric measurements.

Results: In the fasting state, fetal abdominal circumference z-scores did not correlate with any of the flow parameters; 120 min after glucose loading, the z-scores correlated positively with the changes in umbilical vein (r = 0.25, p = 0.010) and fetal liver blood flow (r = 0.25, p = 0.009), but not with those in ductus venosus (p = 0.84). In simultaneous multiple linear regression analyses, the effects of the changes in umbilical vein or fetal liver blood flow after OGTT on the fetal abdominal circumference z-scores were almost equal to or greater than other parameters related to fetal size (body mass index, fasting plasma glucose, parity, and sex). Fetal heart rate increased after OGTT, but did not influence the association between the blood flow parameters and fetal abdominal circumference z-scores.

Conclusions: Changes in umbilical vein and fetal liver blood flow after glucose loading were positively related to fetal abdominal size.

Keywords: Blood flow; Doppler ultrasound; ductus venosus; fetal liver; glucose; umbilical vein.