PREGNANCY

According to the March of Dimes Organization, smoking during pregnancy can be detrimental to the developing fetus.  Smoking nearly doubles a woman’s risk of having a low-birthweight baby. Low birthweight babies, classified as those who weigh less than 5 1/2 pounds at birth, face an increased risk of serious health problems during the newborn period, chronic disabilities (such as cerebral palsy, mental retardation and learning problems), and even death. These health consequences can be devastating and can inflict major emotional as well as economic costs on the families, and on communities²⁸.    

Smoking has also been associated with a number of pregnancy complications. Smoking early in pregnancy appears to increase a woman’s risk of having an ectopic pregnancy. In an ectopic pregnancy, the embryo becomes implanted in a fallopian tube or other abnormal site instead of the uterus. With the rarest of exceptions, these pregnancies do not result in the birth of a baby, and must be removed surgically or with drug treatment to protect a woman’s life. Smoking also may increase a woman’s risk of miscarriage. 

“Cigarette smoking also appears to double a woman’s risk of developing placental complications (which occur in about 1 percent of pregnancies). These include placenta previa, a condition in which the placenta is attached too low in the uterus and covers part or the entire cervix; and placental abruption, in which the placenta separates from the uterine wall before delivery. Both can result in a delivery that jeopardizes the life of mother and baby, though a cesarean delivery can prevent most deaths”²⁸. 

“Babies of mothers who smoke are twice as likely to die from sudden infant death syndrome (SIDS) as babies of non-smokers. Babies who are exposed to cigarette smoke after birth also may face an increased risk of SIDS; however, recent studies suggest that exposure to smoke while still in the womb poses a bigger risk”²⁸.   

Children who are exposed to cigarette smoke while in the womb may be at increased risk of lasting problems, including asthma. There is also an increased risk for learning and behavioral problems. One recent study found that boys whose mothers smoked during pregnancy were four times more likely than sons of nonsmokers to have serious behavioral problems²⁸. 

One study states that cigarette smoking is the foremost modifiable risk factor for adverse pregnancy outcomes. Nicotine is a suspected fetal neuroteratogen (substance that causes fetal neurological abnormalities). There is concern that nicotine may achieve toxic levels during pregnancy if nicotine replacement therapies are prescribed at doses used in the nonpregnant state. The experimenters looked at ten pregnant women and measured the amount of nicotine and cotinine that was excreted in the urine.  The clearance of nicotine (60%) and cotinine (140%) was significantly higher during pregnancy. The study indicated that no downward dose adjustment needs to be made for nicotine replacement therapy during pregnancy¹⁵.

Another study looked at the accuracy of self-reported smoking habits in smoking pregnant women and estimates the prevalence of exposure to passive smoking (secondhand smoke) in non-smoking pregnant women. The study looked at 509 pregnant women whose information about smoking habits were taken from the prenatal records of 496 women (97%). Serum samples from these women were tested for cotinine, which is a substance that exists after nicotine is metabolized. They found that of 407 women, reporting to be non-smokers, 6% were most likely smokers, and 3% had cotinine levels suggesting exposure to substantial passive smoking (secondhand smoke)²⁶. Of 60 women, reporting smoking 1-10 cigarettes per day, 32% were likely to smoke more. The conclusion of the study is that if the true facts about exposure to tobacco smoke are not revealed, a number of women who might benefit from information and support regarding to cessation of smoking, might miss the opportunity of such assistance, resulting in increased risks for both the woman and her fetus²⁶. 

There are some questions regarding the effect of tobacco on the placenta.  Structural changes in the placenta might contribute to the lower birth weight seen among infants born to mothers who smoke cigarettes. In this study, a morphologic examination and a stereologic quantitation of placentas from mothers who smoked cigarettes and who did not smoke cigarettes during pregnancy were performed. Twenty-five placentas from mothers who did not smoke cigarettes, 15 placentas from mothers who smoked 5 to 10 cigarettes per day, 16 placentas from mothers who smoked 11 to 20 cigarettes per day, and 16 placentas from mothers who smoked >20 cigarettes per day were delivered at term after normal pregnancies and were fixed by dual perfusion²⁵. No differences were shown in the total volume of placenta between the groups. The estimated volume and surface area and the calculated lengths for villous capillaries were significantly reduced in all 3 groups of smokers. A significant increase of the trophoblast volume was observed in the mothers who smoked cigarettes. They concluded that cigarette smoking during pregnancy influences the placental vasculature. The reduced dimensions of fetal capillaries in villi may affect the placental blood flow, and the diminished area for exchange of gases and nutrients between the mother and the fetus will increase the risk of fetal undernourishment²⁵.

It has been determined that smoking increases the overall healthcare cost.  However, much of the work on estimating health care costs attributable to smoking has failed to capture the effects and related costs of smoking during pregnancy. The goal of this study was to use data on smoking behavior and birth outcomes to estimate neonatal costs attributable to maternal smoking during pregnancy. The sample is approximately 25 000 and is observed from a variety of states. Analysis is used to estimate the relationship of smoking to probability of admission to an NICU and, separately, the length of stay for those admitted or not admitted to an NICU. The analysis showed that maternal smoking increased the relative risk of admission to an NICU by almost 20%. For infants admitted to the NICU, maternal smoking increased length of stay while for non- NICU infants it appeared to lower it. Over all births, however, smoking increased infant length of stay by 1.1%. NICU infants cost $2496 per night while in the NICU and $1796 while in a regular nursery compared to only $748 for non-NICU infants². The combination of the increased NICU use, longer stays and higher costs result in a positive smoking attributable fraction (SAF) for neonatal costs. The SAF across all states is 2.2%. Across the states looked at, the SAF varied from a low of 1.3% in Texas to a high of 4.6% in Indiana². These results further confirm the adverse effects of smoking. Among mothers who smoke, smoking adds over $700 in neonatal costs. The smoking attributable neonatal costs in the US represent almost $367 million in 1996 dollars; these costs vary from less than a million in smaller states to over $35 million in California². These costs are highly preventable since the adverse effects of maternal smoking occur in the short-run and can be avoided by even a temporary cessation of maternal smoking. These cost estimates can be used by managed care plans, state and local public health officials and others to evaluate alternative smoking cessation programs². 

 As it can be seen, smoking during pregnancy can be harmful to the developing fetus.  It should also be noted that after pregnancy it is not safe for women to begin smoking again.  The secondhand smoke can be harmful to the infant and any other children in the home in addition to the fact that nicotine is found in breastmilk and is then passed to the infant.  One statistic that stood out is that if all pregnant women in the U.S. stopped smoking, there would be an estimated 10 percent reduction in infant deaths, this according to the U.S. Public Health Service²⁸.