Is Nicotine safe while breastfeeding?

Summary of use during breastfeeding

Smoking tobacco reduces milk yield and often results in early cessation of breastfeeding. Stopping smoking during pregnancy may increase the likelihood of initiating breastfeeding postpartum.[1] Maternal smoking is also a major risk factor for sudden infant death syndrome.. Some authors and guidelines have advocated use of nicotine replacement products in smoking mothers to reduce the risk to breastfed infants of inhaled smoke and toxins in maternal cigarette smoke.[2-4] However, others point out that based on animal data, nicotine may increase the risk of sudden infant death syndrome and might interfere with normal infant lung development. These authors recommend against using any form of nicotine in nursing mothers.[5,6] No studies have been performed to resolve these issues, but one report indicates that a neonate exposed to nicotine during pregnancy had withdrawal symptoms that were relieves somewhat by maternal breastmilk.[7] Only nicotine patches have been formally studied in nursing mothers, but a mother with high doses of oral nicotine pouches developed hyperprolactinemia of about 25 times normal.

The Academy of Breastfeeding Medicine considers nicotine replacement products to be compatible with breastfeeding, with the type of product determined by the clinical needs of the breastfeeding mother.[4] An alternate smoking cessation product may be preferred during nursing.

Effects on the breastfed infant

Maternal smoking is a major risk factor for sudden infant death syndrome (SIDS). Nicotine is thought to be the causative factor by reducing the dopamine content of the carotid bodies and reducing the infant's ability to autoresuscitate during hypoxic episodes.[5]

Nicotine in the breastmilk of smokers also appears to reduce the heart rate variability in male breastfed infants.[9]

In a study of the infants of 5 mothers who were using 21 mg nicotine patches for smoking cessation, the infants' average Denver Developmental age was equivalent to their chronological age.[2]

An infant was born to a mother who was vaping nicotine throughout pregnancy and postpartum partially provided breastmilk to her infant because of a limited breastmilk supply. Her infant was initially admitted to the newborn nursery and transferred to the NICU after 4 hours due to signs and symptoms of respiratory distress, grunting and tachypnea, and required high-flow nasal canula oxygen therapy at 2 L/minute with FiO2 of 25%. Laboratory values and imaging were consistent with transient tachypnea of the newborn. On the second day of life, the newborn’s examination was notable for irritability, tremors, hypertonia, weak suck, high-pitched cry, and sneezing. The neonate’s Finnegan scores remained persistently elevated over the first 24 hours with the highest score of 18. Morphine was administered throughout most of the newborn’s NICU stay, with the highest dose of 0.1 mg/kg/dose every 3 h. Morphine was gradually weaned beginning on day 8 of life; however, by day 17, the infant’s Finnegan scores had begun to trend upward and the infant’s clinical assessment was notable for a high-pitched cry, irritability, difficulty sleeping after feeds, and excessive sucking. Consequently, the morphine dose was increased. It was noted that symptoms were more pronounced when breastmilk intake was minimal, leading to speculation of postnatal exposure through breastmilk. The mother admitted to using e-cigarettes, taking several puffs throughout the day. The infant had elevated cotinine levels in urine. The mother stopped vaping in order to breastfeed and by day 33, morphine was discontinued and the infant was discharged home the next day.[7]

Effects on milk supply

Cigarette smoking reduces milk yield.[10,11] This effect may be caused by nicotine, although other factors associated with smoking may also play a role.[12-14]

In a study of 15 nursing mothers who were using nicotine patches in decreasing doses from 21 mg to 14 mg to 7 mg over several weeks, their average milk production was 17% lower than average literature values as judged by infant milk intake. The study did not directly compare the milk production of smokers to nonsmokers, however. In this study, infant milk intake during maternal use of the nicotine patch was similar to that during smoking.[2]

A woman had a history of mild galactorrhea and breast engorgement from risperidone that had improved with the discontinuation of risperidone 1 year prior. She had serum prolactin levels measured. She had quit smoking 2 to 3 weeks prior to having her prolactin levels checked and had started using 10 to 12 nicotine pouches daily (6 mg each) to help with nicotine cravings. Initial laboratory values showed a prolactin level of 312 mcg/L (reference 5.2 to 26.5 mcg/L). Because she was trying to get pregnant, she discontinued nicotine pouches immediately after learning of high prolactin levels. Prolactin levels normalized 2 and 3 days later (13.4 mcg/L and 8.8 mcg/L, respectively).[15]

Levels in milk

Maternal Levels. Fifteen lactating women who smoked an average of 17 (range 14 to 20) cigarettes daily were studied during smoking and after smoking cessation while using nicotine transdermal patches in decreasing doses of 21, 14 and 7 mg daily. One woman who smoked 6 cigarettes daily was started on the 14 mg daily patch. The women supplied milk samples from before and after each nursing on the day before attending their clinic appointments which were 2 to 3 weeks apart. Milk was analyzed for nicotine and its metabolite cotinine. During smoking, the milk nicotine concentration was about 200 mcg/L. Steady-state milk nicotine concentrations during the 21 mg patch was about 175 mcg/L, which was not statistically different from smoking levels. Likewise, milk cotinine levels were not different between smoking and the 21 mg patch. Milk nicotine concentrations were lower than smoking levels with the 14 and 7 mg patches at about 140 and 70 mcg/L, respectively. Cotinine milk levels were also lower with these doses than with smoking. Calculated daily infant nicotine equivalent dosages (nicotine plus cotinine) were as follows: 25.2 mcg/kg with smoking, 23 mcg/kg with the 21 mg patch, 15.8 mcg/kg with the 14 mg patch, and 7.5 mcg/kg with the 7 mg patch. On average, infants ingest 1.9% of the maternal weight-adjusted dosage of nicotine and about 7.8% of the maternal weight-adjusted dosage when cotinine was also considered.[2]

A paper reporting a new method of analyzing nicotine found that nonsmokers (n = 2) had milk nicotine concentrations averaging 0.049 mcg/L of nicotine, passive smokers (n = 5) had an average concentration of 0.18 mcg/L and smokers (n = 5) had an average concentration of 1.59 mcg/L.[8]

Infant Levels. Nine breastfed infants with an average age of 4.8 months (range 2.5 to 21 months) whose mothers were using nicotine patches for smoking cessation had plasma concentrations of cotinine measured during maternal use of a 21 mg nicotine patch. Infant plasma cotinine averaged 22 mcg/L (range 19 to 25 mcg/L), which averaged 13.4% of the simultaneous maternal cotinine plasma concentrations.[2]

An infant was born to a mother who was vaping nicotine and postpartum while partially breastfeeding the infant. On approximately day 18 of life, cotinine was detected in the neonate’s urine at 83 mcg/L, (reference range <5 mcg/l) and urine nicotine was <5 mcg/L. The mother stopped vaping so she could breastfeed her infant and on day 27, the infant’s urinary cotinine level had dropped to less than 5 mcg/L.[7]