OBSTETRIC DETERMINANTS OF VASOPRESSIN (AVP) PLASMA LEVELS IN LOW BIRTH WEIGHT NEWBORN INFANTS

Abstract

At birth plasma AVP concentrations in full-term newborns are higher than contemporaneous material levels and they vary in accordance with the type of delivery.We measured the variations of AVP plasma concentration at birth and at the third day of life in 10 low birth weight (LBW) vaginally delivered infants (BW 2126±430.92 g;GA 35.5±3.13 w.), and as control those of 14 full-term vaginally delivered infants (BW 3421±346.98 g;GA 40.07±0.196 w.) and of 10 healthy, full term newborns, born by caesarean section (BW 3454±354.62 g;GA 40.2±0.78 w.). AVP cord blood levels of LBW vaginally delivered infants result significantly higher (48.1±29.36 pg/ml;p(0.01) than those of full-term vaginally delivered ones (24.89±21.80 pg/nl;p<0.01). At birth AVP blood levels in both vaginally delivered groups are significantly higher than in caesarean section (Full-term 24.89±21.80;L8W 48.1±29.36 vs. 8.14±3.83 pg/ml;p<0.01 and p<0.001, respectively);they are also significantly higher if compared with AVP vaginal delivery blood levels in third day of life (p<0.00l). On the contrary, there is no statistically significant difference between AVP blood levels of the vaginal delivery groups and AVP blood levels of the caesarean section group,at the third day of life (Full-term 7.09±8.45; LBW 6.3±2,90 vs. 5.15±1.73 pg/ml). In our study, the type of delivery appears an important determinant to attribute the significant increase of AVP blood levels in full-term and LBW newborns.