Smoking during pregnancy is a well known risk factor for increased morbidity and mortality for the fetus. Smoking has been associated with premature birth, intrauterine growth retardation and congenital malformations. Knowing that active smoking presents an increased health risk, the question arises as to whether there are also any increased health risks to the fetus when a pregnant woman inhales smoke generated by others?
This is the passive or second-hand smoke that may be present in an office setting, restaurant, or home environment. Secondhand smoking exposes a pregnant woman to all of the same toxins and carcinogens, but at lower dosages than smoke inhaled directly.
Sidestream smoke is the major component of second hand smoke that is considered most harmful. This is the smoke coming off the end generated by a cigarette, cigar, or pipe. Sidestream smoke is considered four times more toxic than than directly inhaled smoke due to its higher content of carcinogens. Some of the carcinogens include tar, nicotine, ammonia, benzene, vinyl chloride, arsenic, acetaldehyde, formaldehyde, lead, carbon monoxide, phenol, styrene, butane and toluene.
A recent study published in the March, 2011 issue of Pediatrics by Leonardi-Bee, claims to be the first world review to examine the effects of second hand smoke exposure during pregnancy. They did a combined review of 19 other studies from North America, South America, Asia, and Europe and found a 23% increased risk of stillbirth, 13% increased risk of having a child with congenital anomalies and a higher risk of having a decreased birth weight in newborns by 33 gm.
How much second hand smoke is dangerous? Currently available studies do not tell us. The effects of second hand smoke at the various stages of a woman’s pregnancy have not been definitively studied and conclusions are not available.
What type of congenital anomalies were found with second hand smoking?
The congenital anomalies that are associated include heart defects, clubfoot, cryptorchidism (failure of descent of the testes), neural tube defects, anencephaly (defect in formation of part of the brain), spina bifida (defect in spinal formation), cleft palate and craniosynostosis (premature closure of the sutures of the skull).
Some of the defects may be due to the exposure of the fetus to toxins through inhalation of sidestream smoke. Other theories have implicated the father’s active smoking causing damage to the genetic material at the time of conception.
Preventing second hand smoke exposure is important for women both before and during pregnancy. There is no doubt that second hand smoke has deleterious effects on the fetus with both higher risks of stillbirth and congenital malformations. This blog stresses the importance of obstetricians asking and advising, not only the direct smoking history of a patient, but also the passive smoking exposure that a patient experiences during the pregnancy. This includes emphasis on paternal smoking habits, with all efforts being made to suggest programs for smoking cessation and maintaining smoke free workplace and home environment.
Tags: birth defects, cigarettes and pregnancy, damage to the fetus, health, healthy baby, healthy pregnancy, passive smoke exposure, pregnancy, pregnant, safe, safety, second hand smoke and pregnancy, Sids, smoking, smoking and pregnancy, smoking during pregnancy, smoking in pregnancy, smoking while pregnant, Sudden Infant Death Syndrome