Objective : To determine whether maternal smoking during pregnancy causes impairment in growth after birth. Design : Longitudinal study. Setting : Six medical university centres of six towns of north, central, and south Italy. Subjects : 12987 babies (10238 born from non-smoking mothers, 2276 from mothers smoking one to nine cigarettes a day, and 473 from mothers smoking >/=10 cigarettes a day) entered the study. Main outcome measures : Difference in weight gain between children born to smoking mothers and those born to non-smoking mothers. Weight was measured at birth and at 3 and 6 months of age. Maternal smoking habit was derived from interview on third or fourth day after delivery. Results : Compared with children born to mothers who did not smoke during pregnancy, the birth weights of children born to mothers who smoked up to nine cigarettes a day were 88 g (girls) and 107 g (boys) lower; in children born to mothers who smoked >/=10 cigarettes a day weights were 168 g and 247 g lower. At six months of age for the first group the mean weight for girls was 9 g (95% confidence interval -47 g to 65 g) higher and for boys 64 g (-118 g to -10 g) lower than that of children born to mothers who did not smoke. The corresponding figures for the second group were 28 g (-141 g to 85 g) lower for girls and 24 g (-136 g to 88 g) lower for boys. Conclusions : The deficits of weight at birth in children born to mothers who smoked during pregnancy are overcome by 6 months of age. These deficits are probably not permanent when smoking habit during pregnancy is not associated with other unfavourable variables (such as lower socioeconomic class). Key messages: Key messages The issue of weight growth in babies born to smoking mothers remains controversial Data obtained in this study confirm the association of smoking during pregnancy with lower birth weight The reduction of weight at birth, however, may be completely overcome by 6 months of age

Background The aim of this study was to evaluate the association between red blood cell (RBC) transfusions on the risk of death, retinopathy of prematurity (ROP), bronchopulmonary dysplasia (BPD), and necrotizing enterocolitis (NEC) in very low birth weight (VLBW) infants. Study Design and Methods This is an observational study. Data were entered prospectively into the study database at the time of the first transfusion. Clinical characteristics, adverse events, and outcomes of the patients transfused in the first 28 days of life were compared with the population of VLBW infants not transfused during the same period. The association among birth weight, gestational age, comorbidities, and the number of transfusions was estimated with a Poisson regression model. The association between the composite outcome and the occurrence of death, ROP, or BPD separately considered and a set of covariates was estimated with a logistic regression model. Results We enrolled 641 VLBW infants, 42% of whom were transfused. Transfusions were associated with the risk of developing the composite outcome, independently from other conditions; this risk correlated with several transfusions ≥ 3 (odds ratio: 5.88, 95% confidence interval: 2.74–12.6). ROP and BPD were associated with several transfusions ≥ 3. Conclusion We observed an association between RBC transfusions and the composite risk of death or ROP, BPD, and NEC.