Foetal growth of kidneys, liver and spleen in intrauterine growth restriction: "programming" causing "metabolic syndrome" in adult age

Abstract

Background/aims: Epidemiological studies in humans link adult disease to abnormal growth in utero. In addition to general malnutrition of the foetus, preferential blood flow to the brain and heart may furthermore deprive organs such as the liver, spleen and kidneys of oxygen and macro- and micronutrients. As a consequence, these organs may not develop normally, which predisposes the individual to the so-called metabolic syndrome (syndrome X) in later life. The effects of foetal undernutrition on the growth of some abdominal organs were investigated by comparing the volume of the kidneys, spleen and liver in small-for-gestational-age (SGA) newborn infants with that in appropriate-for-gestational-age (AGA) newborn infants.

Methods: In 25 randomly selected AGA infants and 25 SGA infants, who were subdivided into three gestational age groups (<30, 30-36 and 37-40 wk) the volumes of the liver, kidneys and spleen were determined by ultrasonography. Organ volumes were estimated using the standard ellipsoid formula (longitudinal x anteroposterior x transverse diameter x pi/6). Liver/kidney, liver/spleen and kidney/spleen volume ratios were also determined.

Results: The volumes of the kidneys and liver differed significantly between AGA and SGA infants in all three gestational age groups (p < 0.0018 and p < 0.029, respectively). The fact that the spleen volume differed only in the 37-40 wk group (p = 0.0002) may indicate that there is a graded relationship across the whole range of normal birthweight. The correlation between the liver volume and birthweight differed significantly between SGA and AGA infants (r = 0.56 vs 0.84, p = 0.04). On the other hand, the volume ratios between the three organs were the same in all groups (p > 0.15).

Conclusion: In intrauterine growth retarded infants, foetal growth of the liver and kidneys is more impaired than the body as a whole. Retarded foetal development of these organs may cause metabolic dysfunction, which predisposes to the group of diseases included in the so-called metabolic syndrome or syndrome X.