Submission Number: CIN-4-330-159

Abstract Number: 2

PLACENTAL INSUFFICIENCY - INTRAUTERINE GROWTH RESTRICTION IN HUMANS.

Cinzia L Paolini, Stefania Ronzoni and Anna Maria Marconi

University of Milano, Milano, Italy ¹

Abstract:
Intrauterine growth restriction (IUGR) is associated with increased perinatal morbidity and mortality. A classification of the severity of IUGR in human pregnancies has been proposed based on the evaluation of fetal heart rate (FHR) and pulsatility index of the umbilical artery (PI): group 1 (normal FHR and PI), group 2 (normal FHR, increased PI), group 3 (abnormal FHR and PI). This classification of clinical severity should reflect different degrees of placental insufficiency in utero. Many studies performed in humans both at the time of fetal blood sampling in utero and at the time of elective cesarean section have shown significant differences between normally grown (AGA) fetuses and IUGR fetuses according to their clinical severity: oxygenation, acid base balance and lactate concentrations are comparable in AGA and IUGR of group 1. On the contrary, IUGR of groups 2 and 3 are associated with increasing degrees of hypoxemia and lacticacidemia. Furthermore, the transplacental glucose gradient is significantly increased in IUGR pregnancies compared to normal pregnancies and the magnitude of the increase is related to clinical severity. The maternal-fetal concentration difference of most essential amino acids is reduced in IUGR. Fetal-maternal amino acid transfer rates have been further investigated in vivo by stable isotopes methodologies. The feto-maternal leucine enrichment ratio significantly decreases from AGA to IUGR pregnancies of the 3 groups. This shows that there is an impaired leucine flux across the IUGR placenta, even in the less severe fetuses. In addition, in IUGR pregnancies the placental transport of essential amino acids is significantly reduced in vivo. These findings suggest that both placental metabolism and transport are altered in intrauterine growth restriction in humans.

Keywords: intrauterine growth restriction, human, feto-placental unit, metabolism

This abstract is being presented at: 11:00 AM in session:
Minisymposium IV: FETAL ORIGINS OF ADULT DISEASES