55 Birth -Size Distribution in 4050 Infants to Mothers with Diabetes Type 1. A Nation-Wide Study.

Abstract

Objective: In spite of improved metabolic control during pregnancy, mothers with insulin-dependent diabetes mellitus (IDDM) are still at risk of delivering macrosomic infants.1 The aim of this study was to further characterize birth-size distribution in infants to IDDM mothers.Methods: Population-based cohort study of infants (n=4,050; 2,054 boys)born to IDDM mothers in Sweden between1998-2007 with a gestational age (GA) of 28-42 weeks. Birth weight (BW) and birth length (BL) were retrieved from the Medical Birth Registry and expressed as SD-scores for healthy infants. Fatness was defined as BWSDS-BLSDS > +2, and leanness as BWSDS-BLSDS < -2.2 Values are mean (SD).Results: Mean BW was 3744(749) g and GA 37.6(2.1)wks. Mean BWSDS for IDDM-infants was 1.28(1.48) and BLSDS 0.70(1.24). Both SDS were normally distributed. The 90th percentile for BWSDS was 3.21 and the 97.5th percentile was 4.41. Fatness was seen in 6.3% and leanness in 0.44% of the IDDM-infants. Term infants had higher BWSDS (mean1.31 vs 0.99, p< 0.001), higher BLSDS (mean 0.73 vs 0.53, p< 0.001) and higher proportion of fatness (6.7 vs 3.7%, p< 0.01) than preterm IDDM infants, whereas leanness was similar in the two groups. Girls had higher BWSDS (1.36 vs 1.19, p< 0.001) and higher BLSDS (0.76 vs 0.65, p< 0.01) than boys, whereas fatness/leanness was equally distributed among sexes.Conclusion: Distributions for both BW and BL are significantly right-shifted in infants to IDDM mothers. A larger shift in BW- compared to BL- distribution indicates disproportional fetal growth. Further studies on causes and consequences of this early growth-deviation are warranted.