The effects of smoking in pregnancy on factors influencing fetal growth

Abstract

Aim: To evaluate the influence of maternal smoking during pregnancy on factors influencing fetal growth. Methods: Thirty newborns of smoking mothers were prospectively compared with 60 newborns of non-smoking mothers. Pre-albumin, albumin, triglycerides, glucose, insulin, insulin-like growth factor I, IGF binding protein 3, pH, lactic acid, erythropoietin and hemoglobin concentrations were measured in umbilical cord blood. Results: Infants of smoking mothers had a significantly lower birth weight (3418 ± 533 vs. 3863 ± 503 g; p < 0.001), length (50.5 ± 2,6 vs. 52.3 ± 1.9 cm; p < 0.001) and head circumference (34.6 ± 1.8 vs. 35.8 ± 1.1 cm; p < 0.001) than controls. They also had significantly lower insulin (3.2 (2.0-4.9) vs. 5.8 (4.6-7.1) mU/L; p = 0.008), insulin-like growth factor I (54.4 ± 32.5 vs. 93.8 ± 54.5 μg/L; p = 0.001) and IGF binding protein 3 (1664 ± 432 vs. 1943 ± 421 μg/L; p = 0.01) concentrations, than controls. Infants of smoking mothers also had significantly higher hemoglobin (167 ± 14 vs. 157 ± 13 g/L; p = 0.002) and erythropoietin (42.3 (25.1-72.4) vs. 26.3 (21.9-30.9) U/L; p = 0.03) than controls, but not pH or lactate concentrations. There was no significant difference in pre-albumin, albumin, triglycerides and glucose concentrations. Conclusions: Smoking during pregnancy causes symmetrical fetal growth impairment, possibly due to decreased oxygen transport to the fetus and decreased concentrations of fetal insulin, insulin-like growth factor I and IGF binding protein 3. © 2006 The Author(s).