Indiana University Bloomington

Indiana Prevention Resource Center (IPRC)

The Effects of Other Substances on the Fetus

January is Fetal Impact of Substance Abuse Awareness Month.  The first article focused on alcohol use during pregnancy and the Fetal Alcohol Spectrum Disorders (FASD) which can result from it. This second article addresses the effects of tobacco, cocaine, marijuana, and heroin on the developing fetus. Awareness is extremely important to help reduce the number of these babies who have been exposed to harmful substances. “In the United States, the estimated number of drug-exposed infants born each year ranges from 100,000 to 375,000” (Born Addicts: Drug-Addicted Babies in the United States, 2012).

One substance that is unfortunately used often during pregnancy is tobacco. Even though most people are aware that smoking harms the smoker’s body in many ways, they may be unaware that tobacco also negatively affects the fetus. “Approximately 10% of women reported smoking during the last three months of pregnancy” (CDC, 2014). Tobacco use can affect the placenta (the source of the baby’s food and oxygen) in a way that may cause it to separate from the uterus too early and cause bleeding. This is extremely dangerous and can even kill the mother and/or the baby. Smoking reduces the amount of oxygen that is available to the mother and the baby and increases the chance of having a miscarriage (CDC, 2014). It also increases the baby’s heart rate and increases the risks of premature birth, low birth weight, the baby developing respiratory problems, stillbirth, birth defects, and sudden infant death syndrome (SIDS) (, 2014).  In addition to the problems surrounding the pregnancy and birth of the baby, maternal smoking can cause long-lasting problems for the child. Children exposed to tobacco in utero are at an increased risk for developing behavioral problems, learning disorders, or even becoming smokers themselves.

Secondhand smoke is harmful as well. According to the CDC, in the United States, about 88 million children and adults who do not smoke are exposed to other people’s smoke. Even though these people have avoided the temptation to smoke themselves, their health still might be affected by it. Exposure to cigarette smoke during pregnancy increases the chance that baby will be born with a lower birth-weight.  Additionally, babies who are around cigarette smoke are more likely to have ear infections, more frequent asthma attacks, and a greater likelihood of dying from SIDS (CDC, 2014).

Tobacco continually affects the fetus throughout the duration of the pregnancy, so reducing one’s tobacco use or quitting altogether at any point in the pregnancy will reduce the odds of smoking-related complications for mother and baby. It is important to note that it is best to quit smoking without the use of medication (Mayo Clinic, 2014). If it is too difficult to quit without an additional aid, the woman should contact her doctor to see what medications are safest for her baby. Also, avoiding places where smoking is allowed will benefit both the mother and baby in the long term.

Cocaine is another substance that can damage the fetus if used during pregnancy. If a pregnant woman uses cocaine, the drug travels through the placenta and enters the baby’s circulation. Unfortunately, cocaine stays in the baby’s body for longer periods of time than that of an adult. While it could take 30 hours to break down the cocaine in a mother’s system, it could take anywhere between two to seven days for a newborn (Organization of Teratology Information Specialists, 2014).

Using cocaine during pregnancy can have many detrimental effects on the mother and baby. The babies of pregnant women who abused crack cocaine used to be called “crack babies” and were thought to have severe and irreversible damage. While research has determined that this was an exaggeration, it does not take away from the fact that cocaine does negatively impact the fetus. For example, babies exposed to cocaine in utero often are born prematurely and present with low birth weight, a smaller head circumference, and are shorter in length (National Institute on Drug Abuse, 2010).  Additionally, these babies tend to be more irritable and jittery; they have interrupted sleep patterns, visual disturbances, and problems with sensory stimulation. Effects from a mother’s cocaine use sometimes can affect the child’s long-term development as well. This includes problems with sustained attention or behavioral self-control, delays in learning, abnormal muscle tone, slower growth rate, language difficulties, and an increased need for special education (Organization of Teratology Information Specialists, 2014).

Even though marijuana has been legalized in some states, research has shown that it should not be used while pregnant. Similar to other substances, marijuana can travel through the placenta to reach the fetus. When smoked, marijuana can disrupt the oxygen supply and nutrients to the baby. This can lead to restrictions in growth, such as overall length, foot length, head size, and body weight. Additional problems resulting from marijuana use can include delayed commencement of breathing, features similar to those found in fetal alcohol syndrome, an exaggerated startle response, tremors, poor eye-sight, a ventricular septal defect (also known as a “hole in the heart”), and a greater risk of developing asthma, chest infections, or other breathing problems (University of Washington Alcohol & Drug Abuse Institute, 2013). In terms of developmental problems, babies of mothers who used marijuana can have poorer verbal skills, memory, reasoning ability, and motor skills. They also are more likely to be fearful, impulsive, inattentive, hyperactive, and delinquent (University of Washington Alcohol & Drug Abuse Institute, 2013). Even though research on marijuana use during pregnancy is still being conducted, it is definitely safer for pregnant women to avoid using marijuana.

A problem that has been associated with marijuana use during pregnancy has been that it seems to reduce nausea. Morning sickness is common within the first few months of pregnancy;  however, sometimes, the nausea persists longer than a few months. Some pregnant women  use marijuana to reduce the feelings of nausea (, 2009).  While more research is needed on this issue, any marijuana use poses a risk for the developing fetus.  Women may think that medical marijuana is safe because it’s ‘medicine. ‘   It is still, however, marijuana.  Women who are dealing with pregnancy-related nausea should ask their doctors about less risky ways of treating it.  

Another substance that should not be used during pregnancy is heroin. There are very serious consequences associated with heroin use during pregnancy for the mother and the baby, including increased risk of placental abruption.  Placental abruption is the separation of the placenta from the wall of the uterus before birth; this can cause severe bleeding and can even lead to death for the mother and the baby. Neonatal abstinence syndrome (NAS) can also occur in a newborn who is born dependent on the drugs that the mother used during her pregnancy. NAS results in withdrawal symptoms for the baby, including excessive crying, fever, irritability, seizures, slow weight gain, tremors, diarrhea, vomiting, and possibly death (National Institute on Drug Abuse, 2014). Other risks  include premature birth, low birth weight, still birth, and sudden infant death syndrome (SIDS) (March of Dimes, 2013).

Exposure to any substance negatively affects the fetus; however, the following video shows the impact that heroin specifically has on this newborn baby. Baby Born Addicted to Heroin Video. It is so devastating to see the suffering that this baby must endure, which is why spreading the word about this issue is very important.

General Guidelines
While there is still research needed in order to more fully understand the effects that each drug individually has on the mother and baby’s systems, there are some guidelines that should be applied to any drug use during pregnancy. If a pregnant woman is attempting to quit her substance use, she should consult her doctor immediately. When using narcotics, quitting immediately without medical assistance can pose risk to the fetus; however, when using tobacco or marijuana, it is best to stop as soon as possible (March of Dimes, 2013). It has been mentioned that drugs are often passed to the baby through the placenta; however, after birth, some types of drugs can also be transmitted through the mother’s breast milk (Organization of Teratology Information Specialists, 2014). Overall, it is best to avoid using any kind of substance while pregnant in order to avoid potential harm to the fetus. Even prescription and over-the-counter drugs should only be used with the approval of a doctor.

*[For more resources on the topics covered in this article, see the IPRC HOME library e-Resources accessible from IPRC homepage or at].

By Heather Dolne, 1/13/2015