EXPOSURE TO ENVIRONMENTAL TOBACCO-SMOKE IN NONSMOKING PREGNANT-WOMEN IN RELATION TO BIRTH-WEIGHT

The objective of this study was to determine whether birth weight is r elated to maternal exposure to environmental tobacco smoke, A cohort s tudy was conducted in a sample of 710 nonsmoking women attending a pre natal education program in the third trimester of pregnancy in La Fe H ospital, Valencia, Spain. The duration of exposure to environmental to bacco smoke in the home, at work, and in vehicles and public places wa s collected by structured questionnaire. Cotinine levers were determin ed in saliva samples, Multiple regression was used to control for infa nt's sex and gestational age and for maternal age, height, prepregnanc y weight, parity, education, social class, and episodic illnesses duri ng pregnancy. The mean birth weight of infants of women with cotinine levels >1.7 ng/ml was 87.3 g lower than that of infants of women with cotinine levels in the range 0-0.5 ng/ml (p = 0.048), Birth weight was negatively associated with average weekly duration of exposure in pub lic places (p < 0.05), whereas mothers exposed to the partner's smoke for up to 14 hours/week had infants 177.2 g heavier than those of unex posed mothers, Although the evidence is weak for an effect of exposure to environmental tobacco smoke on the fetus of nonsmoking pregnant wo men, it may be sufficient to recommend restriction of smoking in enclo sed work- and public places to reduce any risk of growth retardation.