Abstract
New Drug Records
Insect repellants
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Iron-related products
In addition to the old drug, iron dextran, several newer intravenous iron products have become available, including ferric carboxymaltose, ferumoxytol, iron sucrose, and sodium ferric gluconate complex. The two products with information on the use in nursing mothers are ferric carboxymaltose (Injectafer) and iron sucrose (Venofer). Neither of these products caused any notable adverse effects in breasted infants above placebo or oral iron administration to the mother. These two may be preferred because of the published data available. Ferrlecit brand of sodium ferric gluconate complex contains 9 mg/mL of benzyl alcohol, which may make it less desirable for use in mothers of neonates.
Iron chelating agents are commonly used in persons who receive repeated blood transfusions, such as those with thalassemia. Although published data are scant, it appears that oral deferasirox (Exjade and Jadenu) and intravenous deferoxamine (Desferal and others) might be appropriate for nursing mothers. Deferasirox is 99% bound to plasma proteins and thus unlikely to be excreted into milk in large amounts. One woman breastfed her infant while receiving deferasirox and two women receiving deferoxamine breastfed their three infants, all without apparent harm. A third drug, deferiprone (Ferriprox), is both orally absorbed and poorly bound to plasma proteins, so it should be considered inappropriate for nursing mothers at this time. Regardless of the product used, the breastfed infant's iron status should be monitored, because these chelators might decrease the iron content of breast milk.
Signal transduction inhibitors
Signal transduction inhibitors (STIs) are a relatively new class of oral drugs that are mostly used for treating various cancers. Many of these drugs, such as imatinib (Gleevec), which was introduced in 2001, are specifically tyrosine kinase inhibitors. The STI class contains 37 drugs on the U.S. market at last count. STIs are generally less toxic than older cytotoxic chemotherapy, but as would be expected, most have no information on their use in breastfeeding and all have labeling that warns against breastfeeding during therapy. Most STIs are very highly bound to plasma proteins, some more than 99%, which would imply that very little would enter the breast milk. However, some of the drugs have half-lives as long as several days, which raises concerns of accumulation in the infant should they be absorbed from breast milk. Furthermore, many of the drugs are taken daily for prolonged periods, making timing of breastfeeding impractical.
In a few case reports, women safely breastfed their infants while taking a tyrosine kinase inhibitor, and no reports of toxic effects in breastfed infants have appeared in the literature. The drugs that have been used include imatinib (three infants, plus measurements of low milk levels in five mothers), nilotinib (one infant), and dasatinib (one infant). Three of these cases come from an article that reported a Hungarian woman with chronic myeloid leukemia who took imatinib, nilotinib, and dasatinib sequentially in three pregnancies. She then breastfed each infant while continuing the drug with no apparent harm to the infants. 1 Although these cases are not sufficient to establish safety of this class of drugs during breastfeeding, they might provide some basis for a careful trial in highly motivated and properly informed mothers with close monitoring of their infants. Note that some of these drugs have slightly different mechanisms of action and toxicities, so one should not generalize from these few cases, especially for the drugs having very long half-lives. LactMed provides both protein binding and half-life information on each of these drugs. The drug's labeling (package insert) should also be reviewed because many contain boxed warnings about specific toxicities.
Unusual nondrug situations
LactMed contains a number of nondrug interventions that might come up in the course of advising nursing mothers.
Acupuncture
Acupuncture has been used for increasing milk supply. Published studies have found mixed results on acupuncture's effects on serum prolactin and these studies generally do not meet current evidence-based guidelines, partly because of the difficulty in double-blinding and placebo-controlling studies. However, two studies did find a better response to electroacupuncture applied at a traditional site for lactation stimulation than electroacupuncture applied at a site unrelated to milk production. None of the studies reported to date have made an attempt to optimize maternal nursing technique before acupuncture. Acupuncture has also been used to treat engorgement and mastitis, with some modest success.
Body art
Tattooing and piercing are becoming more prevalent in the childbearing population. No data are available on the safety of tattooing during breastfeeding. Theoretical concerns relate to transmission of pigments or infections to the infant during breastfeeding. In the United States, blood donation is not permitted for 12 months after a tattoo as a precaution. Opinion appears to favor not obtaining a new tattoo during breastfeeding.
Piercing of the nipples seems to not interfere with lactation in most cases, although decreased lactation caused by duct obstruction and milk leakage through the piercing tract may occur. Poor latching and milk leakage from the infant's mouth have been reported and a theoretical concern is aspiration of the nipple jewelry by the nursing infant and injury of the infant's mouth and gums. Although these complications apparently have not been reported, nipple jewelry should probably be removed before nursing, and some recommend removal during the entire duration of breastfeeding. Mastitis, sometimes accompanied by reversible hyperprolactinemia and galactorrhea, have both been reported in non-nursing women.
Dialysis
There appears to be no contraindications to breastfeeding by mothers who are on dialysis, although there are only few reported cases. Analysis of breast milk indicates that the predialysis milk concentrations of some solutes are abnormal. Authors who managed one patient suggest that breastfeeding after hemodialysis might be preferable to breastfeeding before hemodialysis. 2
Electrical stimulation
Evidence from a few mothers who received deep brain stimulation for dystonia indicated that no difficulty was encountered with lactation, other than minor discomfort with chest neurostimulators.
Transcutaneous electric nerve stimulation (TENS) is most often used to treat pain. Two small, low-quality studies found it useful for alleviating uterine pain caused by breastfeeding in the early postpartum period in hospitalized women. There are also anecdotal reports on Internet web sites of TENS being used for nipple stimulation to induce lactation in adoptive mothers. However, no scientific data on the safety or efficacy of this use exists.
Imaging
Magnetic resonance imaging (MRI) has no known effect on the nursing mother, her milk, or infant. Likewise, simple X-rays and CT scans appear to be harmless for the nursing mother and her infant. Contrast media used with some MRI and CT procedures are generally safe during nursing, but LactMed should be consulted for information on the specific agent.
High-dose breast radiation for breast cancer therapy can decrease or eliminate subsequent milk production in the treated, but not in the untreated breast. No adverse consequences have been reported for mothers or their infants who choose to nurse from the unaffected breast. Lower radiation doses to the breast in the treatment of Hodgkin lymphoma appear to have only a minor effect on subsequent lactation success, but cranial irradiation for Hodgkin lymphoma can reduce subsequent breast milk production. Women who were treated as children for leukemia with cranial radiation often have difficulty in nursing their infants.
Parenteral nutrition
Four women receiving long-term partial or total parenteral nutrition have reportedly breastfed their infants successfully either fully or partially. One of the mothers required an increase in parenteral nutrition from 5 to 7 days a week while lactating and another required adjustment of her formula. A prominent group encourages lactation among their patients receiving parenteral nutrition if the mother wishes, with the understanding that formula supplementation may be necessary depending on the adequacy of her milk supply. Both the growth of the infants and the mother's metabolic and nutritional status should be monitored closely to assure adequate nutrition for both.
Phototherapy
Laser therapy was used in some Russian studies to prevent and treat lactation mastitis and nipple fissures. A study from Bulgaria compared laser therapy with metoclopramide for increasing serum prolactin and milk supply. However, these studies are rather old and not well controlled. More recent studies found that laser application to cesarean section wounds did not adversely affect serum prolactin, and LED light applied to the nipple improved the pain from nipple lesions 1 day sooner than sham therapy.
Transfusions
A recently published large retrospective study found that women who received red blood cell transfusions during hospitalization for postpartum hemorrhage were about 10% less likely to be breastfeeding at discharge than women with postpartum hemorrhage who did not receive a transfusion. 3 However, other confounders might have contributed to the observed difference.
Footnotes
Disclosure Statement
No competing financial interests exist.