by Dr. Mohammed Shareef

Created on: September 07, 2007

A million babies are born each year in United States who had their moms smoking during their pregnancy. These numbers do not include the passive, involuntary smoking during pregnancy. Not only does smoking have immediate consequences, such as low birth weight, preterm delivery, infant death among others, it also has long term effects, such as obesity, type 2 diabetes, cancer and asthma among several other conditions.

Cigarette smoke is a complex mixture of 4800 compounds of which atleast 60 of them are classified as carcinogens (cancer causing agents), agents affecting respiratory, cardiovascular, reproductive and nervous system. A study by Dr. Fisher's group at the University of California, San Francisco showed that during pregnancy, the cytotrophoblasts, the cells of the placenta, are differentiated to form synciotrophoblasts which are important for nutrient exchange between the mother and fetus. Active as well passive smoking leads to disruption of this differentiation effecting the outcome of pregnancy. Thus mother's smoking effects the life and health right from the early stages of development.
Several studies have shown that maternal cigarette smoking causes perinatal complications such as: premature rupture of the membranes; intrauterine growth restriction; preterm delivery, sudden infant death syndrome and low birth weight. All these effects are due the fetal hypoxia (lowering of oxygen levels) caused by cigarette smoking. A study by Azarbayjani and Danielson, at Uppsala University, Sweden, showed that exposure to phenytoin, a component of cigarette smoke, during the 5th or 6th week of gestation is associated with the formation of cleft lip. Phenytoin affects the embryonic heart leading to development of embryonic hypoxia, ultimately leading to development of a cleft lip. Several other studies have also shown a correlation between maternal cigarette smoking and development of cleft lip and palate.
While lot have previous investigations have focused on the perinatal birth defects, studies are now being reported on long term developmental defects in kids, who were exposed to cigarette smoke while they were in their mother's womb. A study published by Cnattingius's group in a 2004 issue of Journal Cancer Causes Control, on a large cohort of Swedish kids exposed to cigarette smoke as fetuses, examined for risk of brain tumor development, suggested that children who were exposed to cigarette smoke as fetuses had increased incidence of brain tumors compared to kids that were not exposed. The increase was more evident in children between two to four years. Another disease that has been linked to maternal smoking is the development of asthma. Analysis of wheezing and asthma prevalence among 705 fifth grade students from 13 public schools in Chicago by Dr. Richardson's group at School of public health, University of Illinois at Chicago, reported that maternal smoking during pregnancy was associated with increased incidence of asthma in the offspring.
If this is not enough, different studies have shown relationship between the maternal cigarette smoking and the several disorders including hypertension, diabetes, obesity, neurological and behavioral disturbances. Thus, based on the facts present above and several other reports, it is very important that pregnant women should avoid smoking during the gestational period.

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