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Effect of Maternal Cigarette Smoking on
Pregnancy
Complications and Sudden Infant Death
Syndrome
Joseph R.
DiFranza, MD Robert A. Lew, PhD
Journal of Family Practice 1995;40:385-394.
Smoking during pregnancy can have devastating effects on the developing human from
conception of delivery. Infants exposed to maternal smoking can appear perfectly healthy
at birth only to succumb to the Sudden Infant Death Syndrome months later.
Tobacco Induced Abortions
The association of maternal smoking and miscarriage has been investigated in at least
20 studies published over the past 30 years. Tobacco induces between 19,000 and 141,000
abortions in American women each year. Our best estimate is that 115,000
"spontaneous" abortions are actually caused by tobacco each year. This would
represent 19% of all miscarriages experienced by smoking women. Smoking during
pregnancy increases a woman's risk of miscarrying by 24%.
Low Birth Weight
The association of maternal smoking and the delivery of babies weighing less than 2500
grams at birth is the subject of at least 30 studies published over the past 35 years.
Tobacco use is responsible for between 32,000 and 61,000 low birth weight deliveries each
year. Our best estimate is that 53,000 such births are attributable to maternal tobacco
use each year. Smoking accounts for 18% of all low weight births and 45% of such births
among women who smoke during pregnancy. Smoking during pregnancy increases the risk of low
birth weight by 82%. The consequences of low weight births are detailed in the next two
sections.
Neonatal Intensive Care
The most common consequence of low birth weight is the need for treatment in an
intensive care unit immediately after birth. Maternal smoking is the cause of an
estimated 14,000 to 26,000 infant admissions to neonatal intensive care units in the US
each year. Most of these infants will survive unscathed. Others suffer permanent
injuries and thousands die.
Perinatal Mortality
At least 42 studies published since 1959 have measured the effects of maternal smoking
on the death of infants immediately before, or soon after delivery. Smoking is the
cause of an estimated 1900 to 4800 infant deaths annually. Our best estimate is that
3700 infant deaths in the perinatal period are caused by maternal smoking each year in the
US. This represents 7% of all perinatal deaths, and 21% of perinatal deaths among the
offspring of women who smoke during pregnancy. These deaths are caused primarily by low
weight births and premature separation of the placenta. Smoking during pregnancy increases
the risk of perinatal death by 26%.
Sudden Infant Death Syndrome
At least 19 studies concerning smoking and SIDS have been published since 1966. SIDS is
caused by maternal smoking during pregnancy and by exposure of the infant to cigarette
smoke from any source after pregnancy. Hence smoking by the father and other household
members can also cause SIDS deaths. Maternal smoking alone is responsible for an estimated
1200 to 2200 SIDS deaths each year. Additional deaths would be attributed to smoking by
other household members. Our best estimate is that 1900 SIDS deaths are caused by maternal
smoking in the US each year. Maternal smoking is responsible for 35% of all SIDS deaths
in the US, and 66% of SIDS deaths among the infants of women who smoked during their
pregnancy. Smoking during pregnancy triples the risk of SIDS.
Conclusions
Much of the uncertainty reflected in these estimates is due to uncertainty in the
number of women who smoke during pregnancy. The link between maternal smoking and each of
the conditions discussed above is very well established by a rich body of scientific
evidence.
Tobacco products are the cause of major morbidity and mortality among humans from the
time of conception onward. The magnitude of the harm caused by the use of tobacco products
during pregnancy is enormous, but has not been previously appreciated. At least three
times as many infants die of SIDS caused by maternal smoking as are killed as a result of
homicide or child abuse.
Attempts to help expectant mothers to quit smoking have had very limited success. Since
nearly all smoking starts in the teenage years or earlier, efforts to reduce these
deaths should focus on preventing nicotine addition among girls.
This article can be found online at:
http://www.findarticles.com/p/articles/mi_m0689/is_n4_v40/ai_16860682
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