The Influence of Smoking on Intrauterine Fetal Growth and on Maternal Oestriol Excretion

Summary: Of 3,000 patients with singleton pregnancies, 237 (7.9%) smoked more than 20 cigarettes per day. Heavy smoking had a highly significant correlation with intrauterine growth retardation (P<0.001) and subnormal oestriol excretion (P<0.001), but these parameters of fetal welfare were not significantly influenced by light smoking when compared to non‐smokers. Birth weight was lower and the incidence of intrauterine growth retardation was increased in proportion to increasing total consumption of tar and nicotine during pregnancy. It was concluded that heavy smokers should be encouraged to reduce the number of cigarettes smoked to less than 5 per day.