While you're pregnant, one of your greatest responsibilities is to protect your developing baby from harm.
One way you can do this is by avoiding alcohol, tobacco, and certain drugs or medications. 
These substances can easily pass from your bloodstream to your baby's, with serious results. 
Smoking
Your baby can be exposed to harmful chemicals from tobacco before birth, causing numerous problems and even death. 
If you smoke during pregnancy, your baby may: 
<ul>
 <li>Be at life-threatening risk. You're more likely to have a miscarriage, a stillbirth (a baby born dead), or a baby born prematurely (before the end of the 37th week of pregnancy). </li>
 <li>Get less oxygen and nourishment. The nicotine in your blood is passed on to your unborn baby and causes the blood vessels to narrow. The baby then gets less oxygen and nourishment. </li>
 <li>Be born small. Smoking increases the risk that your baby will weigh less than 5 1/2 pounds at birth, notes the&nbsp;<a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=modimes" target="_blank">March of Dimes</a>. </li>
 <li>Have birth defects. Babies whose mothers smoke during pregnancy are more likely to have birth defects, including cleft lip or palate. </li>
 <li>Be at risk for SIDS. If you smoke during pregnancy, your baby has an increased risk of dying from sudden infant death syndrome (SIDS), according to the <a href="http://www.netreturns.biz/healthinfo/bouncelink.aspx?shortcut=acog" target="_blank">American College of Obstetricians and Gynecologists</a>.</li>
</ul>
To give your baby the best protection from these side effects, don't smoke. Also, avoid smoky environments. And don't be afraid to tell family and friends who smoke in your presence that they're putting you and your unborn baby at risk.
Smoking can also harm your baby after he or she is born. If you smoke around your infant, he or she will have an increased risk for respiratory and ear infections, hearing trouble, bronchitis and pneumonia. 
Medications and illegal drugs
Because both prescription and nonprescription medications can harm your fetus, tell your doctor about each drug you take. 
Avoid marijuana and illegal drugs such as cocaine, which can cause your baby to be stillborn, born premature or have birth defects. Cocaine can also increase your risk of heart attack, high blood pressure and seizures. 
Alcohol
There is no safe level of alcohol use during pregnancy, so avoid it altogether. Alcohol can cause a variety of birth defects, the most serious of which is fetal alcohol syndrome (FAS). Babies with FAS are smaller than normal and have facial abnormalities, such as small eye openings. They may also have developmental or learning disabilities. 
Reviewed 3/30/2024

Pregnancy: Substances that can harm you and your baby

If you smoke, drink or use drugs, you could hurt your unborn baby as well as yourself.