Maternal and umbilical venous adrenomedullin and nitric oxide levels in intrauterine growth restriction

Abstract

Objective. To verify whether adrenomedullin (AM) and nitric oxide (NO) concentrations are changed in the maternal and fetal circulation in pregnancies complicated by intrauterine growth restriction (IUGR) compared to normal pregnancies, and to determine any relationship between them.

Methods. Forty-six small for gestational age (SGA) and 34 appropriate for gestational age (AGA) infants were included in the study. Umbilical and maternal venous AM and NO concentrations were determined.

Results. Umbilical NO concentrations in SGA infants (mean ± SD; 176.2 ± 75.8 μmol/L) were significantly greater than in AGA infants (143.4 ± 39.2 μmol/L) (p = 0.015). However, umbilical AM concentrations were similar in SGA and AGA infants with 14.2 ± 4.4 pmol/mL and 14.5 ± 6.2 pmol/mL, respectively (p > 0.05). There was no relationship between NO and AM levels in umbilical blood (r = 0.09, p = 0.40). No difference was found between either AM or NO levels in the maternal plasma of the two groups.

Conclusions. We suggest that NO is increased in the fetoplacental circulation in SGA infants probably as a response to decreased blood flow, whereas AM is not. Additionally, increased NO in the fetoplacental circulation was found to be independent from AM secretion.

Keywords:

• Adrenomedullin
• nitric oxide
• vasodilator peptide
• fetoplacental circulation
• intrauterine growth restriction