Environmental tobacco smoke exposure and perinatal outcomes: a systematic review and meta‐analyses

Abstract

Background. While active maternal tobacco smoking has well established adverse perinatal outcomes, the effects of passive maternal smoking, also called environmental tobacco exposure (ETS), are less well studied and less consistent. Objective: To determine to the effect of ETS on perinatal outcomes. Search strategy. Medline, EMBASE and reference lists were searched. Selection criteria. Studies comparing ETS-exposed pregnant women with those unexposed which adequately addressed active maternal smoking. Data collection and analysis. Two reviewers independently assessed titles, abstracts, full studies, extracted data and assessed quality. Dichotomous data were pooled using odds ratios (OR) and continuous data with weighted mean differences (WMD) using a random effects model. Main results. Seventy-six articles were included with a total of 48,439 ETSexposed women and 90,918 unexposed women. ETS-exposed infants weighed less [WMD -60 g, 95% confidence interval (CI) -80 to -39 g], with a trend towards increased low birthweight (LBW, < 2,500 g; RR 1.16; 95% CI 0.99-1.36), although the duration of gestation and preterm delivery were similar (WMD 0.02 weeks, 95% CI -0.09 to 0.12 weeks and RR 1.07; 95% CI 0.93-1.22). ETS-exposed infants had longer infant lengths (1.75 cm; 95% CI 1.37-2.12 cm), increased risks of congenital anomalies (OR 1.17; 95% CI 1.03-1.34) and a trend towards smaller head circumferences (-0.11 cm; 95% CI -0.22 to 0.01 cm). Conclusions. ETS-exposed women have increased risks of infants with lower birthweight, congenital anomalies, longer lengths, and trends towards smaller head circumferences and LBW.

Clinical and Biochemical Effects of Environmental Tobacco Smoking On Pregnancy Outcome

“…3 The main morbidity of infants were jaundice, chest infection, diarrhea and ear inflammation with statistically significant differences between exposed and non-exposed groups to ETS (X 2 = 15.16, p = 0. 01) ETS-exposed women have increased risks of infants with lower birth weight, congenital anomalies, longer lengths, and trends towards smaller head circumferences [15]. Cotinine level in children's urine statistically differentiated children from exposed homes compared with nonexposed homes [16].…”

Association Between Exposure to Secondhand Smoke During Pregnancy and Low Birthweight: A Narrative Review

“…12,14,17,22,37 One study 10 confirmed that exposure to SHS during pregnancy was a cause of LBW and not merely an association. This study is consistent with previous studies indicating that exposure to SHS during pregnancy significantly reduced birthweight.…”

South African tobacco smoking cessation clinical practice guideline

“…[51] Maternal exposure to second-hand smoke in pregnancy can also increase the risk of low-birthweight children. [52] Although quitting early in pregnancy will produce the greatest benefits, stopping at any stage during pregnancy yields benefits to the fetus and mother, and the child in the postnatal period. [53] Passive smoking increases the risk for asthma, middle ear and recurrent chest infections in children.…”