Pregnancy outcome in North American women. II. Effects of diet, cigarette smoking, stress, and weight gain on placentas, and on neonatal physical and behavioral characteristics

Abstract

This study evaluated the effects of diet, weight gain (low = LWG, < 15 lb; adequate > 15 lb), smoking, and stress on the pregnancy outcomes of 60 women. LWG mothers, compared to adequate weight gain, had lower calorie intakes, shorter gestations (0.5 wk, Dubowitz) smaller placentas (345 ± 65 versus 373 ± 75 g), and infants with lower birth weight 2640 ± 329 versus 3193 ± 307 g), ponderal indices (2.37 versus 2.62), and growth rates. Mothers who smoked had increased calorie intake, but showed no alterations in gestational age of infants or placenta weights. Infants of smokers weighed less than those of nonsmokers (2875 ± 522 versus 3059 ± 511 g), but had a normal ponderal index. LWG or smoking were associated with impaired habituation, orientation, and regulation of state (Brazelton exam). LWG (second trimester) impaired motor performance, visual habituation and orientation, and reflexes. Smoking adversely affected auditory habituation and orientation, and autonomic regulation. LWG and smoking have significant, but separate, detrimental effects on pregnancy outcome.