A new study published in the journal of the American Academy of Pediatrics, reports that smoking just one cigarette per day during pregnancy can double your baby’s risk for a sudden unexpected infant death (SUID). Even if you smoke in the three months before pregnancy and quit during pregnancy, the risk of SUID increases by almost 50 percent.
The link between smoking and crib death, or sudden infant death syndrome (SIDS), is not new (read my blog about it here). These deaths are now grouped under the term SUID. This study is important because it evaluates the risk of SUID and smoking before pregnancy and during pregnancy. It also looked at how the risk is reduced by reducing smoking.
One of the biggest reductions of SUIDs came in the 1990s, when parents were urged to put babies to seep on their backs instead of their tummy’s. The “back to sleep” campaign reduced deaths by about half. Guidelines also stressed the importance clearing all types of choking or strangulation hazards from a baby’s sleep area. However, SUID still claims about 3,700 lives each year.
This new study finds that eliminating smoking completely during pregnancy would decrease SUIDs by another 22 percent. That would save the lives of 800 babies every year.
The link between SUID and smoking is clear. The exact cause is still being studied. The current theory is that nicotine from maternal smoking enters a developing baby’s brain and affects the brain chemical (neurotransmitter) serotonin. Serotonin is important for maintain breathing and arousal during sleep. Nicotine’s affect on a baby’s serotonin may result in an inability to breathe while sleeping.
Researchers from the Seattle Children’s Research Institute reviewed data from over 20 million births and close to 29 thousand SUIDs in which maternal smoking information was available. At the time of the study, between 11 and 12 percent of women admitted to smoking before pregnancy and about 9 percent admitted to smoking during pregnancy. The main findings of the study are:
- Smoking before pregnancy but quitting during pregnancy increases the risk of SUID by about 50 percent.
- Smoking just on cigarette a day during pregnancy doubles the risk of SUID. This occurs during any trimester of pregnancy.
- The more cigarettes smoked per day during pregnancy, the higher the risk of SUID. By 20 cigarettes per day, the risk has tripled.
- Reducing the number of cigarettes smoked during pregnancy reduces the risk. Quitting during pregnancy reduced risk by about 23 percent.
Smoking during pregnancy puts your baby at risk for sudden and unexplained death. That is clear. Even smoking before pregnancy increases your baby’s risk. If the theory that these deaths are due to the effect of nicotine on your baby’s brain, nicotine replacement products or electronic cigarettes may also be dangerous.
Your baby is also at risk from exposure to cigarette smoke after birth. Other studies have found that smoking near your baby can increase SUID risk significantly. Some studies suggest that babies exposed to secondhand smoke could be at a six-times higher risk of SUID.
If you are planning to become pregnant, stop smoking first. Ask for help if you can’t stop on your own. If you find out you are pregnant while you are still smoking, tell your pregnancy care provider and get help to stop. Protecting your baby from nicotine could save your baby’s life.
Maternal Smoking Before and During Pregnancy and the Risk of Sudden Unexpected Infant Death, Pediatrics, April, 2019.