Altered Levels of Neuropeptides in the Placenta of SGA Infants

BACKGROUND: Small for gestational age (SGA) births are associated with adverse health outcomes. Emerging evidence suggests that placental neuropeptides may play a role in foetal growth. However, their involvement in SGA remains underexplored. OBJECTIVE: This study aimed to investigate placental levels of neuropeptide Y (NPY), angiotensin II (Ang II) and their respective receptors (NPY R2, Ang II R1) in SGA pregnancies. METHODS: This study analysed 75 placental tissue samples (SGA = 39 and AGA = 36), collected immediately after birth. Protein levels of neuropeptides (NPY and Ang II) and their receptors (NPY R2 and Ang II R1) were measured using ELISA. Group differences between AGA and SGA were assessed using independent samples t-tests. Associations between placental neuropeptides and neonatal anthropometric measures were examined using linear regression analyses, with adjustments for maternal age, BMI, parity, education and baby gender. RESULTS: SGA placentas had significantly lower levels of NPY (p < 0.05) and Ang II (p < 0.05), while receptor levels (NPY R2, Ang II R1) did not differ significantly. Ang II and Ang II R1 levels were positively correlated with birth weight (p < 0.05), head circumference (p < 0.01) and chest circumference (p < 0.01). CONCLUSION: This study reports lower placental NPY and Ang II levels in SGA pregnancies and positive associations of Ang II and Ang II R1 with birth size. These findings suggest that impaired placental neuropeptide signalling may contribute to SGA birth.