Adequate dietary intake and supplementation at doses to meet recommended daily intake (RDI) are common in lactating parents and are generally considered safe. This section discusses megadoses (or high-dose vitamin intake beyond what is usually needed for adequate dietary intake) in the lactating parent. High-dose vitamins are occasionally recommended for medical conditions and are commonly taken for non-medically indicated reasons.

For more detailed information and references on specific supplements, please refer to LactMed, e-lactancia, NatMed Database, or Mother to Baby.

Megadoses of vitamin C may be used by some people to prevent or treat the common cold. Megadoses of vitamin C (250-1000 mg/day) result in breastfed infants being exposed to vitamin C in doses similar to those given to infants to treat scurvy. ¹ High-dose vitamin C supplementation by the lactating parent is not an indication to pump and dump.

Megadoses of riboflavin may be used for migraine prophylaxis. There is no evidence on breastmilk concentrations or effects on breastfed infants from megadoses of riboflavin supplementation by a lactating parent. However, riboflavin generally has a wide safety margin and high-dose IV riboflavin has been safely used as an adjunct in the management of hyperbilirubinemia in infants. Due to the lack of evidence in the breastfeeding parent, alternatives are preferred if available.¹ High-dose riboflavin supplementation by the lactating parent is not an indication to pump and dump.

Pyridoxine in high doses has been used in the management of neuritis and for lactation suppression early postpartum.

Average breastmilk concentrations appear to increase in a dose-dependent manner based on available literature in studies looking at 6-7.5 mg/day and 10-20 mg/day of pyridoxine supplementation. Studies on breastmilk concentrations and infant exposure are not available for larger megadoses of 300 mg/day or more used to treat neuritis. While breastmilk concentrations would exceed the recommended infant daily intake, they would be unlikely to exceed the daily dosage used to prevent isoniazid related neuritis in infants of 1 mg/kg even at higher megadoses.¹  A published case of a newborn with tremors reported that the tremors ceased when the mother stopped her vitamin B6 supplementation, however her dose was not reported. The newborn’s vitamin B6 blood level was approximately 4 times above the normal range, and it was hypothesized that the high vitamin B6 transmission was likely transplacental, and not necessarily via colostrum or transitional milk.²

One systematic review did not find consistent evidence of lactation suppression with pyridoxine doses of 450-600mg/day for 5-7 days, and no significant adverse effects were reported with the use of pyridoxine for lactation suppression in 2 of the trials included in this review. However, the authors did not clarify if no significant adverse effects occurred for the mother, infant or both. Two trials demonstrated 95% efficacy in suppressing lactation with short-term, high-dose pyridoxine, whereas 5 trials showed no efficacy of high-dose pyridoxine on milk production or prolactin levels.²

While data on infant exposure and safety are limited and lactating individuals should be informed of the potential risk of lowered milk production with megadoses of pyridoxine, there is no absolute indication to pump and dump.

Vitamin B₁₂ has a wide safety margin in humans. Replacement doses should correct breastmilk levels among lactating individuals who are B₁₂ deficient. High-dose Vitamin B₁₂ in those with normal B₁₂ levels would be unlikely to create clinically significant increases in milk levels.¹ There is no absolute indication to pump and dump.

While high-dose biotin has not been studied in lactating individuals, biotin has a wide safety margin.¹ There is no absolute indication to pump and dump.

Vitamin D levels in breastmilk are highly variable between lactating individuals based on their baseline vitamin D status, supplementation dosage, BMI, and sunlight exposure. High-dose vitamin D supplementation for those with borderline or normal vitamin D levels resulted in breastfed infants receiving increased vitamin D.^3–5 Maternal supplementation of 6,400 IU daily for 7 months with increased seasonal sun exposure resulted in milk levels of 900 IU/L, adequate for infant recommended daily intake.⁴ However, there are no professional policy statements or accepted protocols by major professional organizations indicating that it is completely safe and acceptable to supplant the recommended infant daily dose of vitamin D with high-dose maternal vitamin D supplementation. This is likely because the pharmacokinetics of vitamin D supplementation during lactation are nuanced and depend on the type of vitamin D, dose, regimen, and maternal health conditions, including body mass index (BMI). High-dose maternal vitamin D is considered safe for the infant during lactation. Infants who continue oral supplementation of vitamin D while their lactating parent is taking high-dose vitamin D should be evaluated for the necessity of continuing oral vitamin D.⁶ There is no absolute indication to pump and dump.

Data on high-dose vitamin K supplementation are limited. High maternal doses of vitamin K₁ were found in one study to decrease the risk of infant vitamin K deficiency in infants who also received a standard vitamin K dose intramuscularly immediately after birth⁷. Vitamin K₂ is also found in human milk as menaquinone-4 (MK-4). High doses of vitamin K₂ and MK-4 supplements  have been studied in postmenopausal women for bone health, but there is no information on the safety of high-dose K₂ or MK-4 supplements during lactation. Vitamin K2 doses less than 1000 mcg are likely safe during lactation, with no absolute indication to pump and dump.¹