Effects of IUGR on the development of very low birthweight children

Studies of the effects of intrauterine growth failure among very low birthweight (VLBW < 1.5 kg) preterm children have mainly pertained to childhood (Sung et al, 1993; Pena et al, 1988; Robertson et al, 1990; Calame et al, 1986). Results have been confounded by the fact that some researchers have compared the children to control children of similar birthweight, whereas others compared them to control children of similar gestational age.

Robertson et al (1990) in Canada examined school performance at 8 years of preterm, small for gestational age VLBW infants and compared it to that of VLBW children born appropriate for gestational age. The IUGR children did not differ in school performance when compared to either birthweight- or gestational-age-matched controls. All the VLBW groups had significantly inferior outcomes when compared to a normal-birthweight control group.

In Cleveland we compared the school age outcomes of a cohort of 51 VLBW children who were born IUGR (with birthweights less than-2 SD for gestational age), to 198 VLBW born appropriate for gestational age. The groups did not differ in maternal socio-demographic characteristics, with the exception that more mothers of the appropriately grown (AGA) children were married (67% vs. 48%, respectively). Mothers of the IUGR children had a significantly higher rate of pregnancy hypertension. More IUGR than AGA children were multiple births (31% vs. 9%) and IUGR children had a significantly higher gestational age (32 vs. 29 wks) and lower birthweight (1113 g vs. 1192 g) compared to the AGA population. The AGA children had significantly more neonatal problems including lower 5-minute Apgar scores and a higher incidence of respiratory distress syndrome and apnea of prematurity. The populations thus differed in maternal marital status, birthweight, gestational age, and the rates of neonatal problems. No overt intrauterine infections were diagnosed.

At 8 years of age AGA children had higher rates of cerebral palsy (25% vs. 6%), but this difference was not significant. No significant differences in intelligence, language, visual-motor abilities, fine motor abilities, and academic achievement were noted between the AGA and IUGR children.

Based on the literature reported, we conclude that intrauterine growth retardation does not appear to impose an added disadvantage at school age over and above that of very low birthweight.