In utero exposure to cigarette smoking influences lung function at birth

Abstract

To avoid the possible confounding effects of postnatal exposure to tobacco smoke, we investigated possible effects of uterine tobacco smoke (UTS) exposure upon infant lung function shortly after birth.Infants with no major disease, in one maternity ward in Oslo, Norway, participating in a cohort study established in 1992/1993, were included in the present study (n=803). Exposure information, assessed as maternal active and passive smoking during pregnancy and other personal and environmental factors, was obtained by questionnaire. Tidal flow-volume (TFV) loops (n=802) and compliance (Crs) and resistance (Rrs) of the respiratory system (n=663) were measured at a mean age of 2.7 days.In girls, the TFV ratio (time to reach peak expiratory flow to total expiratory time (t PEF/t E)), and Crs were significantly lower with active as well as passive maternal smoking compared to nonexposure to UTS. Respiratory rate and Rrs were not significantly influenced by UTS exposure. However, in linear regression analysis adjusted for confounding factors (including respiratory rate), t PEF/t E and Crs, but not Rrs, were related to maternal active but not passive daily smoking. One daily cigarette corresponded to a change in t PEF/t E of -0.0021 (95% confidence interval (95% CI) -0.0040 to -0.0002) and a change in Crs of -0.026 mL·cmH 2 O (95% CI -0.045 to -0.007 mL·cmH 2 O). The decrease was 0.023 and 0.29, respectively, in infants of an average smoker.Maternal smoking during pregnancy adversely affected tidal flow-volume ratios in healthy newborn babies, as well as the compliance of the respiratory system in girls, independently of the reduced body size also resulting from maternal smoking.

Diagnosis of asthma in children under five

“…Summarising this evidence, three separate studies have shown that babies born to mothers who smoke, or who are atopic, or (interestingly but with no explanation) have hypertension in pregnancy, have abnormal lung function shortly after birth, presumably a reflection of an abnormal intra-uterine process. [19][20][21] Three prospective studies (Tucson, Boston, Perth) showed that in babies with VAW, lung function was abnormal prior to the first episode of wheeze. [22][23][24] Unlike in older children and adults, two studies showed no evidence of bronchial hyper-reactivity in VAW.…”

Analysis of Polycyclic Aromatic Hydrocarbons in Amniotic Fluid Samples From Smokers and Nonsmokers

“…Studies with various PAHs in rodent models have clearly shown that certain PAH cause not only teratogeneis, but also at elevated risk of cancer (59)(60)(61)(62). Studies have also clearly shown also that exposure to environmental carcinogens and the resulting effect on the developing offspring is a time-dependent phenomena, with specific gestational times being more clearly susceptible to the effects of carcinogenic compounds than other times (63)(64)(65)(66)(67)(68). As a result, exposure to carcinogenic PAH at early stages of pregnancy and fetal development has a much greater impact than late term exposures.…”

Paediatric Problems of Cough

“…Two studies using tidal breathing indices of lung function, 14,15 and one using the squeeze technique to produce partial flow volume curves 16 have clearly demonstrated that infants have abnormal lung function very soon after birth; risk factors include a maternal history of atopy, maternal smoking and (interestingly and quite unexplained) maternal hypertension during the pregnancy. One group has suggested on the basis of complex physiological measurements that it may be abnormal airway wall compliance rather than calibre which is important in virus associated wheeze.…”