Nicotine is a toxic chemical naturally found in tobacco plants and released during smoking. It is very addictive and affects the heart, respiratory, reproductive system and lungs in addition to other side effects.1 For a review of how smoking affects your baby see Smoking While Breastfeeding. This article looks in more detail at how nicotine in breast milk might affect the breastfed baby and answers frequently asked questions.
Does nicotine get into breast milk?
Yes, nicotine is readily absorbed into breast milk from the mother’s blood whenever she smokes or uses nicotine replacement therapy 2 and her baby will also breathe in nicotine directly if exposed to side smoke.
How do nicotine levels in breast milk compare to passive smoking?
Bajanowski et al found nicotine levels in a baby’s blood were much greater from passive smoking than from ingesting nicotine in breast milk.3 However another older study found ten times as much cotinine (a metabolite of nicotine with a much longer half life that can be measured in blood, urine, saliva, hair and nails) in breastfed babies of smoking mothers compared with bottle fed babies of smoking mothers suggesting more nicotine came via the milk. 4
What does nicotine in breast milk do to baby?
Nicotine in breast milk can:
- Reduce a baby’s appetite as nicotine is a known appetite suppressant and nicotine can flavour the milk 5
- Lead to vomiting and nausea if a mother is smoking 20 cigarettes or more daily 6.
- Cause diarrhoea (Fisher, 2006)
- Increase baby’s heart rate (Fisher, 2006)
- Cause disturbed sleep with higher nicotine exposure because nicotine is a stimulant7
- May increase the risk of SIDS by affecting the way a baby can resuscitate during hypoxic episodes (when the body doesn’t have enough oxygen)8
- Interfere with normal infant lung development (Lactmed, 2020)
- Reduce prolactin levels (a hormone needed for making breast milk) and so affect milk supply although not all studies agree 9.
- Be a risk factor for childhood obesity and thyroid dysfunction 10 11.
Studies have not been carried out on many of the above concerns (Lactmed, 2020).
Can smoking while breastfeeding make baby fussy?
Smoking while breastfeeding may cause fussy behaviour, breast refusal, excessive crying, and increased colic in babies of mothers who smoke more than five cigarettes per day (Mennella et al. 2007).
Does nicotine decrease milk supply?
Some studies indicate nicotine may reduce prolactin levels (a hormone needed for making breast milk) and so affect milk supply however not all studies agree 12.
Should I stop breastfeeding if I smoke?
Although nicotine moves readily into breast milk during smoking (Benowitz et al, 2009), the advantages of breastfeeding are thought to outweigh the risks of nicotine exposure compared with choosing to formula feed. Breastfeeding protects against respiratory infections and has many other health benefits 13. However, Mennella et al suggest more research is still needed:
The removal of nicotine from the list of drugs contra-indicated during lactation does not diminish the need for more research on the effects of smoking during lactation.
cigarette smoke is a complex mixture of chemicals with ~4000 compounds, including >60 carcinogens. Whether compounds other than nicotine and cotonine [a metabolite of nicotine] are transferred to human milk with similar time courses and, if so, what levels are transmitted remain unknown.
It is not clear whether there comes a time when a certain number of cigarettes smoked and hence the amount of nicotine and other substances crossing into milk could outweigh the benefits of breast milk. Certainly it would be better for your baby not to add nicotine to your breast milk. However, until research provides an answer, a smoker’s breast milk has many health advantages for your baby just as all breast milk does. It contains living cells and unique nutrients that both grow your baby’s brain and body normally and protect it from infections. Formula has none of these protective substances and has its own risks 14.
How long does nicotine stay in your breast milk?
The levels of nicotine in milk are highest just after a mother finishes her cigarette and over the following two hours the concentration of nicotine in breast milk falls significantly.15 The half life of nicotine in breast milk is variously quoted as 95 minutes (Mohrbacher, 2020) or 120 minutes (halesmeds.com 2020). This means that nicotine levels in breast milk will have fallen by half after about one and a half to two hours after the mother finishes her cigarette. Based on the general guide that it takes five half lives to clear a substance from the body it may take about ten hours for nicotine to completely leave the mother’s blood or breast milk after one cigarette. In practice although nicotine isn’t stored in breast milk, the levels of nicotine in a mother who smokes regularly throughout the day will accumulate over 24 hours with each cigarette she smokes and breakdown products of nicotine e.g. cotonine remain for much longer.16 Benowitz et al explain:
smoking represents a multiple dosing situation with considerable accumulation while smoking and persistent levels for 24 h of each day.
The authors point out that babies take much longer than adults to eliminate (metabolise) nicotine and cotinine from their bodies.
How long after smoking can I breastfeed?
Waiting as long as possible after smoking gives time for the nicotine levels in breast milk to fall (after two hours levels will have halved). As breastfed babies generally want to feed at least every two hours, general advice is that smoking straight after breastfeeding will give time for nicotine levels to come down before the next breastfeed (Mohrbacher, 2020) But if the baby wants to breastfeed again sooner, breastfeeding is still said to be better than giving formula (Mohrbacher, 2020).
Should I pump and dump after smoking a cigarette?
As nicotine levels are said to gradually fall in your blood and breast milk after smoking a single cigarette, pumping and dumping (throwing away) your breast milk after a cigarette is not necessary to clear the nicotine from breast milk.
What about other chemicals in breast milk and cigarette smoke?
Tobacco contains much more than just nicotine. Lung.org17 credits 600 different ingredients to cigarettes from nicotine, tar, and arsenic to carbon monoxide, lead and many more. When smoked, these 600 chemicals become thousands of harmful pollutants that both you and your baby can breathe in. Passive smoking puts your baby at a much higher risk of sudden infant death syndrome 18. And not only nicotine will cross into breast milk—so will other chemicals.
mothers unable to stop smoking should be informed of the possibility that harmful chemicals derived from tobacco smoke may be transmitted to their infants via breast milk.
See Smoking While Breastfeeding for more about the effects of cigarette smoking during breastfeeding.
What about nicotine replacement therapy?
For more information about nicotine replacement therapy including patches, gum, and sprays, and for guidance on e-cigarettes, vaping and breastfeeding, see Nicotine Therapy, Vaping and Breastfeeding.
Summary
Nicotine has several side effects for your baby when breathed in via cigarette smoke or swallowed via breast milk. Current health guidelines 192021 advise mothers to protect their babies from smoke inhalation by not smoking near their baby, making the home and car smoke-free and not sharing a bed with a baby if they—or their partner—smokes.