Effect of smoking during pregnancy on birth weight, placental weight, and time of third stage of labor

Abstract

Background: Cigarette smoking of the mother during pregnancy is a well-known cause associated with adverse reproductive outcomes, including increase in the incidence of placenta previa, abruption-placentae, and double the risk of infant mortality from all causes. Objective: This study aims to demonstrate the effect of smoking, whether active or passive, on the newborn body weight, placental weight, and the time of the third stage of labor. Materials and Methods: This prospective study involves sixty patients, their ages range between 20 and 32 years, all of them underwent vaginal deliveries, and the lowest accepted packed cell volume (PCV) was 32%. The participants were classified into four groups: active smokers, passive smokers, mixed smokers, and the rest who are nonsmokers, representing the control group. The following data were collected from every: age, gravidity and parity, and number of cigarettes per day, and for each female, the newborn body weight, placental weight, the time of the third stage of labor, and PCV of the mother were estimated. Results: Among these sixty patients who involved in the study, 3% were active smokers, 31% were passive smokers, 27% were mixed smokers, and 39% were nonsmokers; the mean newborn body weight of nonsmokers (control group) was 3252 g; active smokers, 2430 g; passive smokers, 2819 g; and mixed smokers, 2407 g. The mean placental weight in nonsmokers was 527 g; active smokers, 640 g; passive smokers, 551 g; and mixed smokers, 599 g. The time of the third stage of labor in nonsmokers was 6.9 min; active smokers, 12 min; passive smokers, 5.8 min; and mixed smokers, 6.6 min. Conclusions: Cigarette smoking by pregnant women leads to a low birth weight and larger placenta and may interfere with the time of the third stage of labor.