Smoking and pregnancy
during pregnancy causes many detrimental effects on health and reproduction, in addition to the general health effects of tobacco. A number of studies have shown that tobacco use is a significant factor in miscarriages among pregnant smokers, and that it contributes to a number of other threats to the health of the foetus.
Because of the associated risks, women are advised to not smoke before, during or after pregnancy. If this is not the case, however, reducing the daily number of cigarettes smoked can minimize the risks for both the mother and child. This is especially true for women in developing countries where breastfeeding is essential for the child's overall nutritional status.
Smoking before pregnancy
It is recommended for women planning pregnancy to stop smoking. It is important to examine these effects because smoking before, during and after pregnancy is not an unusual behavior among the general population and can have detrimental health impacts, especially among both mother and child as a result. In 2011, approximately 10% of pregnant women in data collected from 24 states reported smoking during the last three months of their pregnancy.Smoking during pregnancy
According to a study conducted in 2008 by the Pregnancy Risk Assessment Monitoring System that interviewed women in 26 states in the United States, approximately 13% of women reported smoking during the last three months of pregnancy. Of women who smoked during the last three months of pregnancy, 52% reported smoking five or fewer cigarettes per day, 27% reported smoking six to 10 cigarettes per day, and 21% reported smoking 11 or more cigarettes per day.In the United States, women whose pregnancies were unintended are 30% more likely to smoke during pregnancy than those whose pregnancies were intended.
Effects on ongoing pregnancy
Smoking during pregnancy can lead to a plethora of health risks to both the mother and the fetus.Women who smoke during pregnancy are about twice as likely to experience the following pregnancy complications:
- premature rupture of membranes, which means that the amniotic sac will rupture prematurely, and will induce labour before the baby is fully developed. Although this complication has a good prognosis, it causes stress as the premature child may have to stay in the hospital to gain health and strength to be able to sustain life on their own.
- placental abruption, wherein there is premature separation of the placenta from the attachment site. The fetus can be put in distress, and can even die. The mother can lose blood and can have a haemorrhage; she may need a blood transfusion.
- placenta previa, where in the placenta grows in the lowest part of the uterus and covers all or part of the opening to the cervix. Having placenta previa is an economic stress as well because it requires having a caesarean section delivery, which require a longer recovery period in the hospital. There can also be complications, such as maternal hemorrhage.
Premature birth
Implications for the umbilical cord
Smoking can also impair the general development of the placenta, which is problematic because it reduces blood flow to the fetus. When the placenta does not develop fully, the umbilical cord which transfers oxygen and nutrients from the mother's blood to the placenta, cannot transfer enough oxygen and nutrients to the fetus, which will not be able to fully grow and develop. These conditions can result in heavy bleeding during delivery that can endanger mother and baby, although cesarean delivery can prevent most deaths.Pregnancy-induced hypertension
There is limited evidence that smoking reduces the incidence of pregnancy-induced hypertension, but not when the pregnancy is with more than one baby.Tic disorders
Other effects of maternal smoking during pregnancy include an increased risk for Tourette syndrome and tic disorders. There is a link between chronic tic disorders, which include Tourette syndrome and other disorders like ADHD and OCD. According to a study published in 2016 in the Journal of the American Academy of Child and Adolescent Psychiatry, there is an especially high risk for children to be born with a chronic tic disorder if their mother is a heavy smoker. Heavy smoking can be defined as ten or more cigarettes each day. With this heavy smoking, researchers have found that there is an increase in risk as high as 66% for the child to have a chronic tic disorder. Maternal smoking during pregnancy is also associated with psychiatric disorders such as ADHD. Concerning the increase risk for Tourette syndrome, there is an increased risk when two or more psychiatric disorders are also existent as maternal smoking leads to a higher chance of having a psychiatric disorder.E.. Maternal Smoking Could Lead to an Increased Risk for Tourette Syndrome and Tic Disorders. Retrieved from https://www.elsevier.com/about/press-releases/research-and-journals/maternal-smoking-could-lead-to-an-increased-risk-for-tourette-syndrome-and-tic-disorders
Effects of smoking during pregnancy on the child after birth
Low birth weight
Smoking during pregnancy can result in lower birth weight as well as deformities in the baby. Smoking nearly doubles the risk of low birthweight babies. In 2004, 11.9% of babies born to smokers had low birthweight as compared to only 7.2% of babies born to nonsmokers. More specifically, infants born to smokers weigh on average 200 grams less than infants born to women who do not smoke.The nicotine in cigarette smoke constricts the blood vessels in the placenta and carbon monoxide, which is poisonous, enters the baby's bloodstream, replacing some of the valuable oxygen molecules carried by hemoglobin in the red blood cells. Moreover, because the fetus cannot breathe the smoke out, it has to wait for the placenta to clear it. These effects account for the fact that, on average, babies born to smoking mothers are usually born too early and have low birth weight, making it more likely the baby will become sick or die.
Premature and low birth weight babies face an increased risk of serious health problems as newborns have chronic lifelong disabilities such as cerebral palsy, mental retardation and learning problems.
Sudden infant death syndrome
is the sudden death of an infant that is unexplainable by the infant's history. The death also remains unexplainable upon autopsy. Infants exposed to smoke, both during pregnancy and after birth, are found to be more at risk of SIDS due to the increased levels of nicotine often found in SIDS cases. Infants exposed to smoke during pregnancy are up to three times more likely to die of SIDS that children born to non-smoking mothers.Other birth defects
Smoking can also cause other birth defects, reduced birth circumference, altered brainstem development, altered lung structure, and cerebral palsy. Recently the U.S. Public Health Service reported that if all pregnant women in the United States stopped smoking, there would be an estimated 11% reduction in stillbirths and a 5% reduction in newborn deaths.Future obesity
A recent study has proposed that maternal smoking during pregnancy can lead to future teenage obesity. While no significant differences could be found between young teenagers with smoking mothers as compared to young teenagers with nonsmoking mothers, older teenagers with smoking mothers were found to have on average 26% more body fat and 33% more abdominal fat than similar aged teenagers with non-smoking mothers. This increase in body fat may result from the effects of smoking during pregnancy, which is thought to impact fetal genetic programming in relation to obesity. While the exact mechanism for this difference is currently unknown, studies conducted on animals have indicated that nicotine may affect brain functions that deal with eating impulses and energy metabolism. These differences appear to have a significant effect on the maintenance of a healthy, normal weight. As a result of this alteration to brain function, teenage obesity can in turn lead to a variety of health problems including diabetes, hypertension, and cardiovascular disease.Future smoking habits
Studies indicate that smoking during pregnancy increases the likelihood of offspring beginning to smoke at an early age.Quitting during pregnancy
Quitting smoking at any point during pregnancy is more beneficial than continuing to smoke throughout the entire nine months of pregnancy, especially if it is done within the first trimester. A recent study suggests, however, that women who smoke anytime during the first trimester put their fetus at a higher risk for birth defects, particularly congenital heart defects than women who have never smoked. That risk only continues to increase the longer into the pregnancy a woman smokes, as well as the larger number of cigarettes she is smoking. This continued increase in risk throughout pregnancy means that it can still be beneficial for a pregnant woman to quit smoking for the remainder of her gestation period.There are many resources to help pregnant women quit smoking such as counseling and drug therapies. For non-pregnant smokers, an often-recommended aid to quitting smoking is through the use of nicotine replacement therapy in the form of patches, gum, inhalers, lozenges, sprays or sublingual tablets. However, it is important to note that the use of nicotine replacement therapies is questionable for pregnant women as these treatments still deliver nicotine to the child. For some pregnant smokers, NRT might still be the most beneficial and helpful solution to quit smoking. It is important that smokers talk to doctor to determine the best course of action on an individual basis.