Relationship between Ghrelin levels of maternal serum, umbilical vein and birth weight

Kim, Jeong Tae; Joo, Jong Kil; Lee, Dong Hyung; Kim, Ki Hyung; Na, Yong Jin; Choi, Ook Hwan

Abstract

OBJECTIVE
Ghrelin is a newly isolated peptide from the stomach. Subsequent studies revealed that ghrelin is expressed in human placenta. Circulating ghrelin levels reflect acute and chronic energy balance in humans. However, it is not proven whether ghrelin plays a role during pregnancy. The purpose of this study was to compare relationship between ghrelin levels of maternal serum, umbilical vein and birth weight.
METHODS
We measured maternal ghrelin levels (N=41) in each trimester and postpartum whose fetus were appropriate-for-gestational age. Also we checked cord blood ghrelin levels at delivery in appropriate-for-gestational age group (N=20) and small-for-gestational age group (N=20).
RESULTS
Ghrelin was detected in all samples from maternal and cord blood. Maternal serum ghrelin levels showed a peak in the 2nd trimester (35.7+/-12.7 pg/mL) and decreased in the late 3rd trimester (26.5+/-10.3 pg/mL). An increase was observed again in postpartum, which was measured at one day after delivery. There was no significant correlation between maternal serum ghrelin level and birth weight (P>0.05), but there was statistically significant correlation between cord blood ghrelin level and birth weight (r=-0.411, P<0.05).
CONCLUSION
Maternal serum ghrelin levels showed a peak around mid-gestation during pregnancy and then, decreased in the 3rd trimester, the time of increased maternal body weight. There was no association between maternal serum ghrelin level and birth weight. But small-for-gestational age neonates present with higher umbilical cord ghrelin level than that of appropriate-for-gestational age neonates. It is conceivable that ghrelin may play a physiologic role in fetal adaptation to intrauterine malnutritional state.