The effects of passive smoking on the human placenta: A gross and microscopic study

Abstract

Introduction: Passive smoking is an established health hazard. Placenta is the main conduit of both nutrients and toxins to the fetus. This study aims to study the effect of passive smoking on the gross and microscopic changes in the placenta among passive smokers. Material and Methods: Gross and microscopic examination was done of the 150 term placentae donated to the department of anatomy; 63 were from gravidas with no history of exposure to tobacco smoke and labeled as controls, whereas 87 placentae were collected from passive smokers. Results: We observed a significant increase in the calcification of fetal surface of the placentae in our cohort (approximately 16% as compared to approximately 13% in the control group). Syncytial knots were found in 43% of the terminal villi in our cohort. Fibrinoid degeneration was observed in approximately 7% of the terminal villi of passive smokers. Hyperplasia of cytotrophoblast was observed in approximately 30% of the terminal villi in our cohort. 14% of the terminal villi of passive smokers had thickening of subtrophoblastic basement membrane. 9.47% of the terminal villi in the passive smoking group were avascular. These findings were statistically significant. Discussion and Conclusion: Passive smoking causes changes in the placenta at the gross and microscopic level. The gross and histologic changes seen in the placenta in this study are known to be associated with adverse fetal outcome. The changes in the placenta can serve as a means of understanding the mechanism of the fetal morbidity due to active or passive smoking.