Human placental IGF-I and IGF-II expression: correlating maternal and infant anthropometric variables and micronutrients at birth in the Pakistani population

Abstract

Aim: To correlate infant birth weight with maternal and infant biometric data, including the expression of placental IGF-I and IGF-II at birth, and levels of serum zinc and ferritin.

Methods: The data consisted of observations from 89 women from Karachi, Pakistan. Placental and cord blood samples were taken immediately following delivery and were subsequently divided into two groups, small and large for gestational age (SGA and LGA).

Results: The mean birth weight was 2.79 kg; the prevalence of SGA being 13.4% (< or =10th percentile); the prevalence of LGA being 23.6% (> or =90th percentile). Placental IGF-I and IGF-II mRNA expression was greater in the LGA group (p < 0.05). Furthermore, a significant correlation was noted between infant birth weight and maternal anthropometric parameters (p < 0.01). Cord zinc levels were also significantly higher in the LGA group (p < 0.05).

Conclusion: Maternal anthropometry, along with placental IGF-I and IGF-II mRNA levels, correlated significantly with infant birth weight suggesting the importance of these growth factors for birth weight outcomes. The higher zinc levels in the LGA group also suggest the importance of this micronutrient in foetal growth. Our results suggest that growth problems have a multifactorial aetiology arising from within the infant rather than due to maternal constraint alone.