FACTORS POTENTIATING THE SMOKING-RELATED RISK OF FETAL GROWTH-RETARDATION

Objective To estimate the risk of fetal growth retardation resulting f rom the interaction between maternal smoking during pregnancy and othe r recognized risk factors. Design Case-control study of prospectively recorded data. Setting Department of Obstetrics and Gynaecology, Unive rsity of Pavia, Italy. Subjects Three hundred and forty-seven singleto n pregnancies with diagnosis of fetal growth retardation and 694 contr ol pregnancies with appropriately grown fetuses. Results The overall o dds ratio for fetal growth retardation associated with maternal smokin g was 2.87 (95% confidence interval, 2.17-3.80). In logistic models th e factors which independently increased the smoking-related risk of fe tal growth retardation were a male fetus, nulliparity, maternal age 20 years or less, a history of first trimester haemorrhage and low (less than 50 kg) pre-pregnancy weight. The combined effect of smoking and caffeine consumption on the risk of fetal growth retardation was found to be additive rather than multiplicative. Conclusions Several factor s can affect the risk of fetal growth retardation associated with mate rnal smoking. The prenatal identification of these factors could help detect subgroups of women at high risk of fetal growth retardation.