In 2016, Ewa Florek, a toxicologist at Poznan University of Medical Sciences in Poland, and colleagues published an article in the journal Environmental Research reviewing what scientists and physicians know about lactation and smoking. Florek and her coauthors wrote that there are more than 5,000 things present in tobacco smoke, many of which are also found in breast milk or affect breast milk production. Researchers have mostly focused on nicotine, which is one of the major components of tobacco smoke.
When a lactating person smokes, the baby absorbs much more nicotine than if a non-breastfeeding caregiver smoked. Nicotine levels tend to be higher in breastmilk than in the blood, and it hangs around for more than an hour and a half after smoking. Nicotine ingested by the baby in breastmilk can stay in the baby’s bloodstream up to four hours, is processed through the liver, and can increase infant heart rate and decrease respiration rate—how often baby breaths. One chemical that results from the breakdown of nicotine in the liver, cotinine, can stay in baby’s body for up to 40 hours.
In a study published in the journal Pediatrics in 2007, researchers led by psychologist Julie Mennella showed that mothers smoking then breastfeeding interferes with infants’ sleep-wake cycles. One day mothers smoked not in the presence of the infant and then fed babies on demand; another day they did not smoke and then fed babies on demand. The day the mothers smoked, the babies slept an average of 30 minutes less over the three-and-a-half-hour period right after the mothers smoked. The more nicotine the babies had in their systems, the less they slept.
Smoking while breastfeeding also has the potential for longer term consequences for the baby. For instance, rodents that receive nicotine via mother’s milk have differences in brain development and long-term memory in adolescence. Pediatrician Gonca Yilmaz and her colleagues showed in a study published in 2009 in the journal Pediatrics International that a baby’s exposure to tobacco smoke increases the likelihood of ear infections and upper and lower respiratory tract infections and slows down infant growth, perhaps because nicotine suppresses baby’s appetite and desire to breastfeed. There is also some evidence that heavy smoking during breastfeeding may increase the risk of your child developing acute lymphoid leukemia. And while breastfeeding typically reduces the risk of sudden infant death syndrome (SIDS), if you smoke while breastfeeding, there’s not the same reduction in risk.
In terms of lactation and breast milk composition, smoking can also have an effect. There is some evidence that smoking disrupts milk production, resulting in lower volumes of milk, as well as milk release from the breast during feeding. These issues may contribute to the shorter breastfeeding durations that have been observed for mothers who smoke. Multiple groups of researchers have reported that the concentration of fat, especially healthy fatty acids, in breastmilk tends to be lower in people who smoke. This might be a problem, as some of these fats—including Docosahexaenoic acid (DHA)—are necessary for brain development in babies. Breast milk from parents who smoke also has lower levels of iodine, vitamin C, and vitamin E.
Now that you’ve heard the possible consequences of smoking and breastfeeding, let’s talk about ways to minimize those consequences for you and your baby. If you are currently smoking and breastfeeding, it will likely be tough to quit, but it is possible. And it is probably worth it for your health and your baby’s health.
First, talk to your doctor or midwife. There are many smoking cessation products that are safe to use while breastfeeding, but some aren’t. If your care provider doesn’t know much about this, it’s okay to ask for a referral to someone who does. For instance, some medical centers have special programs available to help you quit smoking that involve medical and psychological support. Mental health support is something else you can seek out either upon the recommendation of your care provider or on your own. Talk therapy, mindfulness, and other strategies may help you quit smoking or cut back.
