Maternal cocaine use during breastfeeding

Cocaine is a fast-acting and highly addictive central nervous system stimulant that acts on the sympathetic arm of the autonomic nervous system, in addition to the dopaminergic (reward) and other neurotransmitter systems within the brain. It is thought to elicit its rewarding and psychotropic properties via blockade of the transporter responsible for dopamine recovery from the synapse, leading to increased dopaminergic stimulation in critical brain “reward” sites.¹ In this way, cocaine produces both systemic and psychotropic pharmacologic effects, including increased heart rate and blood pressure, improved performance on tasks of vigilance and alertness, and a sense of euphoria, confidence, and well-being.¹ Cocaine is most often abused intra-nasally, where a portion of the dose is also absorbed orally following swallowing of mucus; but it can also be smoked and inhaled, or injected. Cocaine use is associated with many substantial health problems, including increased risk of contracting infectious disease, malnourishment, gastrointestinal complications, and acute cardiovascular events (eg, stroke, myocardial infarctions, myocardial arrhythmias), which might affect both maternal and infant health.^2,3

An estimated 5% to 10% of pregnant women in North America abuse cocaine,^4,5 and some of these women might wish to breastfeed their infants. The benefits of breastfeeding for both baby and mother are numerous and have been established in various studies.⁶ These include, but are certainly not limited to, reduction of infant and lifelong morbidity and mortality, enhanced cognitive function, decreased risk of immunologically mediated diseases, and enhanced maternal-infant bonding.⁶ Further, breastfeeding has been shown to have benefits for long-term maternal health, including reduction in the risk of developing cardiovascular disease, diabetes, and breast and ovarian cancers.⁶

Given the advantages of breastfeeding, infants of low socioeconomic status might particularly benefit from being breastfed. This presents a difficult clinical situation. It is paramount for the health care team to balance the risks and benefits—to maximize the potential benefits to the baby from breastfeeding, but to limit the substantial risks from potential infant cocaine exposure.

There are limited reports about the measurement of cocaine in breast milk following maternal intranasal use; however, given its physicochemical properties (pK_a of approximately 8.6), it is expected that cocaine present in the maternal systemic circulation would pass into the breast milk in meaningful amounts and exhibit a high milk-to-plasma ratio.^7,8 Cocaine present in the breast milk would then be absorbed orally to a limited degree by the breastfeeding infant, as it is typically broken down in the gut, and the infant might be exposed to limited amounts of the drug.^7–9 However, given that the metabolic capacity to metabolize and clear drugs such as cocaine is not fully developed in neonates,¹⁰ exposure to small doses of cocaine could persist and cause considerable harm.

Few reports exist that have examined the effects of cocaine use during breastfeeding on infant outcomes. Reports show substantial variability in the level of cocaine detected in breast milk,^9,11,12 which might represent methodologic issues in cocaine detection, considerable interindividual variability in cocaine pharmacokinetics, or important differences in levels of cocaine use. Sporadic adverse effects, including seizures, hypertension, tachycardia, agitation, and irritability, have been reported in infants after exposure to cocaine by ingestion when applied to the nipple as a local anesthetic¹³ and by ingestion via breast milk.^7–9

Given the important benefits of breastfeeding for infant and maternal health,⁶ the Society of Obstetricians and Gynaecologists of Canada recommends that the decision to breastfeed be made on an individual basis after discussing and weighing the benefits of breast-feeding and the potential risks of infant cocaine exposure with the patient.¹⁴ For addicted mothers who elect to breastfeed but continue to use cocaine intermittently, breastfeeding should be delayed sufficiently after cocaine use to allow for drug elimination (approximately 24 hours).^10,15 Topical application of cocaine to the nipples is dangerous and contraindicated during breast-feeding.¹⁵ Furthermore, women who are regular cocaine users should be provided with concurrent addiction counseling,¹⁶ be encouraged to remain abstinent while nursing, and be provided with sufficient information about the increased risks of adverse neonatal effects (eg, seizures, tachycardia, and irritability). In selected cases cocaine can be measured in milk and, when clinically indicated (eg, suspected adverse effect), also in neonatal blood.¹⁶ Further, because cocaine use has been associated with a higher incidence of HIV infection,¹⁷ and those with HIV infection in developed countries are advised not to breastfeed,¹⁸ it is important to be aware of the serologic status of these women.

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