The impact of secondhand smoke exposure on the pregnancy outcome: a prospective cohort study among Egyptian community

Background Secondhand smoke (SHS) exposure gained lesser interest than active smoking. There is evidence from previous studies that SHS exposure had negative effects on fetal growth. This study aimed to examine the effect of smoke exposure on pregnancy outcome and to evaluate the level of nicotine urinary end-product cotinine in pregnant women in the late trimester. We included 36 women with a history of SHS exposure and 48 women without a history of exposure; all were in last trimester of pregnancy. We measured cotinine level in urine and followed the two groups until delivery and recorded fetal outcomes. Fetal biophysical parameters and blood flow waveforms were measured using B-mode and Doppler ultrasonography, respectively. Results The total range of the urinary cotinine creatinine ratio (CCR) concentration in the SHS exposed pregnant women was 0.01–0.2, IQR = 0.18 ng/mg.cr, versus 0.01–0.1, and IQR = 0.03 ng/mg.cr in the non-exposed group. The mean value as well as the mean rank of CCR was significantly higher (0.1 ± 0.08 ng/mg.cr., 40.3 respectively) in the exposed pregnant women as compared to the non-exposed pregnant women ((0.04 ± 0.02), 29.3 respectively, p value