Background Human placenta may be capable of glucose release due to the presence of Glucose-6-Phosphatase (G6Pase). This release may be from placental glycogen. The authors hypothesised that there would be differences in G6Pase activity and glycogen content in normal pregnancy and small for gestational age (SGA) pregnancies.

Methods 48 subjects were recruited to the Appropriate for gestational Age (AGA) group and 48 subjects to the SGA group. SGA was defined as an ultrasound measurement of abdominal circumference <fifth centile prior to delivery. SGA was further divided into two groups. Group 1 (N = 29) were subjects with Abnormal umbilical artery Doppler (AD) (PI >95th centile) and Group 2 (N=19) with Normal Doppler (ND). The placentas were collected postdelivery and analysed for G6Pase activity and glycogen content.

Results There was no significant difference in G6Pase activity in the AGA group and SGA group (9.42±2.79 vs 9.1±2.68) mg/min, (p=0.675) and between the SGA ND and SG AD (8.9±2.66 vs 9.6±2.7) mg/min, (p=0.435). Glycogen content in the AGA group was significantly lower compared to the SGA group (3.87 (2.89–5.35) vs 6.2 (4.4–10.35), p=0.001) per mg protein but no significant difference in the glycogen content in SGA ND compared to SGA AD (p=0.242).

Conclusion G6Pase activity is similar in AGA and SGA pregnancies. SGA placentas contain more glycogen than AGA subjects which is not explained by G6Pase activity. SGA ND and AD pregnancies display no differences in G6Pase activity and glycogen content.