Janet Liston B Pharm

Abstract

This paper both reviews the current literature and explores anecdotal information as reported by Nursing Mothers' (now Australian Breastfeeding Association) breastfeeding counsellors relating to breastfeeding and the use of alcohol, caffeine, nicotine and marijuana. All of these drugs do enter breastmilk to some extent and can have a detrimental effect on the production, volume, composition and ejection of breastmilk, as well as a direct adverse effect on the infant. Breastfeeding mothers should be encouraged to restrict their intake of these so-called recreational drugs. It is acknowledged that this is a particularly stressful period in a mother's life and that she may need additional support and practical suggestions to limit the exposure of these drugs to the infant.

Keywords: breastfeeding, alcohol, caffeine, nicotine, marijuana
Breastfeeding Review 1998; 6(2): 27-30

INTRODUCTION

For every family, adjusting to a new child is a stressful time. A new mother may find herself turning to caffeine, nicotine, alcohol or even marijuana as a way of coping with her new life. In many cases a mother will not even recognise these substances as drugs. All of these drugs do enter breastmilk to some extent and can have a detrimental effect on the production, volume, composition and ejection of breastmilk, as well as a direct adverse effect on the infant.

This paper reviews some of the current literature relating to breastfeeding and the use of recreational drugs, as well as anecdotal information as reported by Nursing Mothers' (now Australian Breastfeeding Association [ABA]) breastfeeding counsellors. A woman's choices depend on her knowledge base. Many mothers will be unaware of the potential impact of her behaviour on her ability to breastfeed optimally. This information may empower mothers to make informed choices about their use of these so called recreational drugs while they are breastfeeding.

ALCOHOL

Traditionally, women have been told that drinking alcohol will help increase their milk supply and strengthen their baby. Alcohol is generally not considered harmful to the infant if the amount and duration are limited (American Academy of Pediatrics 1989). Some recent studies have suggested that even modest amounts of alcohol may have a significant long-term effect on the breastfed baby (Little 1989; Schulte 1995), making a safe level of alcohol exposure to the breastfed baby hard to define.

Anecdotally, Nursing Mothers' (now ABA) breastfeeding counsellors report instances of babies being drowsy and fussy at the breast after being breastfed by a mother who has been drinking alcohol. Mothers who have been drinking often relate the experience of delayed let-down reflex and a perceived reduced supply. Mothers also report a lower tolerance to alcohol whilst breastfeeding. This may be so, as the low oestrogen levels present during amenorrhoeic lactation are associated with higher blood alcohol levels.

Studies have shown that within thirty minutes of its ingestion, the equivalent of one standard drink changes the smell of breastmilk and has a mildly sedative effect on the baby. Excessive amounts may lead to drowsiness, deep sleep and weakness. A drowsy baby may not suck well which may lead to a reduction in supply. One recent report suggests a 23% reduction (156 ml to 120 ml) in breastmilk production following ingestion of beer (Hale 1998). The altered smell of the milk may account for any fussiness. Any drug that causes drowsiness in the infant may be implicated in SIDS.

Alcohol may theoretically inhibit oxytocin release. Oxytocin is the hormone that causes contraction of the cells surrounding the alveoli and interlobular ducts, forcing milk out into the larger ducts for the baby to remove. Anecdotally, one drink relaxes the mother and improves the let-down reflex whereas large doses of alcohol are believed to have an adverse effect on the let-down or milk ejection reflex. Studies have shown that maternal doses of alcohol greater than 1-2 g/kg can interfere with the let-down reflex (Cobo 1973), though there is considerable variation between individual mothers.

A case often referred to is that of Binkiewicz et al (1978) who noted a four-month-old breastfed infant who developed Pseudo-Cushing Syndrome. The mother was consuming over fifty 12 oz beers and other alcoholic beverages per week. Physical examination of the infant revealed her to be obese (97th percentile for weight) and short (below the 3rd percentile for height). The child's facial appearance was described as 'balloon-shaped' and 'moon-shaped'. The child's appearance and infant growth charts gradually returned to normal when the mother stopped drinking. The safety of consuming even moderate amounts of alcohol has been brought into doubt by a study by Little (1989). Motor development skills were found to be significantly lower in infants regularly exposed to alcohol through breastmilk compared to infants not exposed. Significant declines in motor scores were found in infants whose mothers consumed one standard drink daily. In the first year of life the infant's brain is developing so rapidly and with such complexity that any drug which interferes with that development may have untold long-term effects. Infants in the first few weeks of life detoxify alcohol at approximately half the rate of an adult and liver maturation is not complete until the infant is about three months old (Schulte 1995). Consequently alcohol exposure to a younger infant may have a greater effect than alcohol exposure on an older breastfeeding infant. There is evidence that some drugs have extended half-lives in infants and tend to accumulate. There is a suggestion that some component of breastmilk may inhibit hepatic cytochrome P450 metabolism (LeGuennec & Billion 1987). This metabolism is involved in ethanol metabolism and could lead to delay in elimination of alcohol from the infant.

Interestingly, whereas alcohol appears in the milk at levels approximately equal to that in the mother's bloodstream, no acetaldehyde (the toxic metabolite of alcohol) is found in milk even when levels are high in the mother's bloodstream.

Alcohol impairs a mother's functioning, and may make her more susceptible to depression, fatigue and lapses in judgement. Like any nutritionally vacant food or beverage, too much alcohol can divert the appetite from necessary nutrients.

It is then wise to minimise alcohol exposure to the breastfeeding infant, especially in the first three months. Some recommendations for limiting alcohol exposure include choosing low alcohol drinks, eating before and while drinking, avoiding breastfeeding for two to three hours after drinking and if necessary to express and store alcohol-free breastmilk for use after moderate to heavy drinking.

CAFFEINE

Caffeine is contained in a wide variety of beverages, food and medication. The consumption of coffee, tea, cola-based soft drink and chocolate are a part of our everyday life.

The amount of caffeine found in breastmilk after the consumption of a known amount can vary considerably due to individual differences in absorption and elimination. Peak levels of caffeine are found in breastmilk approximately 60 minutes after ingestion. One study estimated that the average dose to breastfed infants after heavy maternal caffeine intake (750 mg/day or 6-8 cups of coffee per day) was 0.6-0.8 mg/kg/day.

It is important to note that caffeine is used as a respiratory stimulant at a dose of 5 mg/kg/day in premature infants in the treatment of apnoea and near-miss SIDS. Newborns metabolise caffeine very slowly, the half-life of caffeine being 97.5 hours in a neonate, 80 hours in a newborn and 2.6 hours in a six-month-old. The hepatic cytochrome P450 enzyme system is involved in the metabolism of caffeine, and as noted previously, some component of breastmilk is believed to inhibit this system. This potential delay in elimination by the infant could result in accumulation of significant amounts of caffeine in the infant.

Nursing Mothers' (now ABA) breastfeeding counsellors often report mothers who consume high volumes of strong tea, coffee or cola complaining that the baby is jittery, colicky, constipated and generally unsettled. Caffeine may also be associated with a poor milk supply and implicated in recurrent mastitis. Careful questioning may be required to ascertain the mother's level of caffeine intake. In my own counselling experience, mothers in a hot climate may be consuming litres of cola-based drink daily. Similarly, I have known several cases of mothers consuming literally 20-30 cups of coffee per day.

Caffeine has also been shown to have an effect on the composition of breastmilk. When a woman drinks more than three cups of coffee a day, during pregnancy and the early phases of breastfeeding, her breastmilk contains one-third less iron than that of a mother abstaining from coffee (Nehlig & Debry 1994). A decrease in haemoglobin and haematocrit in mothers drinking coffee and their babies has also been observed. It is worth noting that iron deficiency anaemia is prevalent in countries where there is heavy coffee consumption.

Caffeine is approved by the American Academy of Paediatrics for use by breastfeeding mothers. The current recommendation concedes that while occasional use appears to have little effect on the breastfeeding infant, it would seem advisable to restrict caffeine consumption to less than 300 mg/day (approximately three cups of coffee - see table) whilst breastfeeding. The mother should be warned that smoking has been found to accentuate the effects of caffeine in breastfed babies. If the mother uses a cup of tea or coffee to relax and improve the let-down reflex, another hot beverage may be as effective. It has been suggested that decaffeinated drinks, herbal teas, soup or water-based squashes may be used as alternatives to caffeine-based drinks.

Note: Methods of preparation and size of cups can vary considerably. Coffee can be boiled, filtered, percolated or prepared as espresso, Greek or Turkish 'mud' or soluble coffee. The extraction efficiency of caffeine differs for each type of preparation and ranges from 75-100%. Cup size varies from 30-190 ml. The content of caffeine varies from 19-160 mg of caffeine according to the type of coffee, size of the cup and country. Daily consumption of caffeine in the general population is 202-283 mg, which represents 2.7-40 mg/kg/day in males and females 20-75 years old.

Milligrams of caffeine per 150ml cup
Brewed or filtered coffee	90 mg
Soluble instant coffee	63 mg
Decaffeinated coffee	3 mg
Tea	32-42 mg
Cola drink	16 mg
(Nehug & Debry 1994)

NICOTINE

It is widely acknowledged that women who smoke during pregnancy do not tend to breastfeed, and are more likely to wean their babies earlier than non-smoking women. Interestingly, this phenomenon appears to be dose related: the more cigarettes smoked the less time spent breastfeeding (Saunders 1990).

Nicotine is quickly absorbed after maternal smoking and has a half-life in breastmilk of about 90 minutes. The extent of exposure of a breastfed infant is difficult to assess since at least part of the exposure is due to 'sidestream' smoke. Sidesteam smoke is not filtered and contains more nicotine, tar and carbon monoxide than 'mainstream' smoke drawn through the cigarette and into the mother's mouth and lungs. The median nicotine concentration in infant urine after exposure via breastmilk or via passive inhalation was 14 ng/ml and 35 ng/ml, respectively. It is suggested that the effects of these two modes of transmission are probably additive (Fulton 1990).

Babies who are 'smoked over' are more likely to be hospitalised and to suffer from respiratory and gastrointestinal illnesses. Studies show that these infants are more likely to be colicky and irritable and to experience a wide range of problems from apnoea (short periods when the baby stops breathing), vomiting, poor growth, squint (strabismus, cast or lazy eye), hearing impairment and unexplained death. Smoking depresses the immune system, leaving both the mother and infant more vulnerable to infection, allergy and other immunodeficiency problems (Minchin 1991).

Nicotine reduces basal prolactin levels which may lead to a decrease in milk supply. Nicotine also causes an adrenaline rush which may inhibit the release of oxytocin and interfere with the let-down reflex. One study clearly suggests that cigarette smoking significantly reduces breastmilk production at two weeks postpartum from 514 ml/day in non-smokers to 406 ml/day in smoking mothers (Hale 1998). In a counselling situation it is always advisable to ask a mother with constant low supply whether she is a smoker.

Nicotine is an appetite suppressant and can alter the taste of breastmilk. Babies may express their distaste for the milk by fussing and struggling at the breast or even refusing the breast. If the mother smokes more than 15 cigarettes a day, infants can exhibit symptoms of nicotine poisoning (Bisdom 1937). These symptoms may include vomiting after a feed, grey skin colour, loose stools, an increased heart rate and restlessness. Classically, the infant can be observed to wiggle and squirm, giving the appearance of trying to frantically 'tread water' and though they appear very tired they seem to find it hard to keep their eyes shut. Symptoms are slowly reversed when the mother decides to cut back or quit her previous smoking habit. However, infants may also suffer withdrawal symptoms such as sleep disturbances, headaches and irritability.

The breastfeeding mother who wishes to quit smoking may find this is an ideal time to do it. Prolactin and the endogenous opioids released during suckling may actually blunt the worst of her withdrawal symptoms (Minchin 1991). Transdermal nicotine patches used in nicotine withdrawal have been used in breastfeeding mothers. Nicotine levels can be expected to be less in patch users than those found in smokers, assuming the patch is used correctly and the mother abstains from smoking. The mother should be made aware that the patch is delivering nicotine into her system constantly and it may be desirable to only wear the patch for part of the day (manufacturer, pers comm 1997).

Exposure to nicotine can also alter the composition of breastmilk. Breastmilk from a mother who smokes contains many chemical by-products of smoking such as nitrates and nitrites, it may contain pesticides and dioxins and have higher cadmium and lead levels than breastmilk from a non-smoking mother (Minchin 1991). Breastfed infants, whose mothers smoke, may have lower levels of certain vitamins. For example, vitamin B12 may be reduced, as it is needed to detoxify cyanide from cigarette smoke (Saunders 1990).

Smokers may choose to give up breastfeeding because they fear contamination of their milk is a greater risk to the baby than artificial feeding. It is important to remember that artificial milks do not have any of the unique nutritional or immunological advantages of breastmilk and that it is preferable to continue breastfeeding. It is actually more important to stop smoking in families where infants are artificially fed (Chen 1989).

To reduce potential harm from smoking all parents should be encouraged to:

• quit if at all possible.
• smoke outside the house and car.
• smoke only AFTER feeding to reduce nicotine exposure. Try to use other comforting techniques for the baby for 90 minutes after smoking. (This is difficult with a young baby who is feeding frequently, but may be possible once baby has established routines).
• avoid vegetables containing considerable amounts of nicotine - eggplant, green and pureed tomatoes and cauliflower. Ten grams of eggplant provides the same amount of nicotine obtained in three hours in a room with minimal tobacco smoke (Laurence 1985).
• breastfeed exclusively for the first six months to maximise the infant's protection against respiratory disease, and continue to breastfeed as long as possible.
• do not take the baby into smoky environments.

MARIJUANA

The active component of marijuana, delta-9-tetrahydrocannabinol (THC) is fat soluble and is rapidly distributed into brain and adipose (fatty) tissue. The analysis of breastmilk in chronic heavy marijuana users shows an eightfold accumulation in breastmilk compared to plasma. Infants exposed to marijuana through breastmilk will test positive in urine screens for two to three weeks.

Breastfeeding infants absorb and metabolise THC and their exposure occurs at a time when growth and development, particularly glial and myelin formation in the central nervous system, is progressing at a rapid rate (Tennes et al 1985; Astley & Little 1990). Animal studies have shown that structural changes occur in the brain cells of newborn animals exposed to marijuana through their mother's milk. Marijuana purportedly impairs DNA and RNA formation. Although long-term studies have not been completed, results observed in humans suggest serious and long lasting effects (Astley & Little 1990).

If the mother smokes marijuana while breastfeeding or in the presence of the infant, there is also the effect of the sidestream smoke to be considered. Infants exposed to marijuana through breastmilk often exhibit signs of sedation, weakness and poor feeding patterns. Marijuana has been implicated in the reduction of basal prolactin levels and therefore, in possible decreased milk production.

Marijuana use causes reality distortion, which may make it hard to cope with an emergency situation, difficulty in performing small motor activity and after the 'high' wears off, a desire for sleep, usually quite deep, in which the mother may be unresponsive to her baby's needs.

The use of marijuana by breastfeeding mothers is contraindicated by the American Academy of Pediatrics. The long-term effects of early exposure, especially on the infant's rapidly-developing brain are unknown. Breastfeeding mothers should be advised not to smoke. It has been suggested that breastfeeding should be avoided if the mother is a heavy user and withheld for several hours after occasional use. Measures should be taken to reduce the infant's exposure to sidestream smoke as discussed previously.

CONCLUSION

In addition to the medical issue, there are also broader social issues in this discussion of breastfeeding and the use of recreational drugs. These encompass the legal ramifications and moral obligations of such use. In this age of increasing litigation, there may be potential for the future generation to apportion blame on the present generation for any harm that the mother's actions may be seen to have had on an infant. Already the Family Court is considering the issues of smoking, alcohol and other drugs in relation to the residence and contact of infants. Breastfeeding mothers should be encouraged to restrict their intake of these so-called recreational drugs. It should be acknowledged that this is a particularly stressful period in a mother's life and that she may need additional support and practical suggestions to limit the exposure of these drugs to the infant. In all cases it should be stressed that while the problem is the mother's use of these drugs while breastfeeding, the choice should be to give up the drug rather than to give up breastfeeding.

Terms used to describe drug levels in the body

AHL:

This is the most commonly recorded adult half-life of the drug. Short half-life drugs are preferred as they generally enter milk at lower levels. They also do not tend to accumulate in the infant's plasma.

M:P:

The milk:plasma ratio. This is the ratio of the concentration of drug in the mothers' milk divided by the concentration of drug in the mothers' plasma. A low (<1.0) ratio is preferred as this is a good indicator that only a small percentage of the drug is transferred into milk.

PK:

The Peak is the time interval from the mother taking the drug until it reaches the highest level in her plasma. It is preferable to choose drugs that have a short peak, and to avoid breastfeeding at the peak.

REFERENCES

American Academy of Pediatrics 1989, Committee on Drugs: the transfer of drugs and other chemicals into breastmilk. Pediatrics 84: 924-936.
Astley SJ, Little RE 1990, Maternal marijuana use during lactation and infant development at one year. Neurotoxicol Teratol 12(2): 161-168.
Binkiewicz A, Robinson MJ, Senior B 1978, Pseudo-Cushing syndrome caused by alcohol in breastmilk. J Pediatr 93: 965-967.
Bisdom W 1937, Alcohol and nicotine poisonings in nurslings. J Am Med Assoc 109: 178.
Chen Y 1989, Synergistic effect of passive smoking and artificial feeding on hospitalization for respiratory illness in early childhood. Chest 95: 1004-1007.
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Tennes K, Avitable N, Blackard C, Boyles C, Hassoun B, Holmes L, Kreye M 1985, Marijuana prenatal and postnatal exposure in the human. Nat Inst Drug Abuse Research Monograph 59: 48-60.

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