The Nephrologist's Role in Supporting and Promoting Lactation

How is milk production affected by CKD? Does the patient need specialized lactation support?

Patients with CKD can breastfeed successfully (2). This is despite the fact that they often deliver preterm, undergo induction, have cesarean deliveries, and receive intrapartum intravenous fluids that contribute to excess breast edema (3). Each of these factors can result in a delay in lactogenesis II, which is defined as the onset of copious milk production, typically occurring between 48 and 72 hours postpartum (4). Because of this, patients with CKD require lactation support early and often. Determining medication compatibility with lactation should be a priority to prevent delays in breastfeeding initiation. Knowledge of breast milk volume per 24 hours can be used to guide decisions about ultrafiltration, diuresis, fluid intake, and dry weight (2, 4). Daily breast milk volume increases rapidly, from <100 mL in the first 2 days postpartum (1–10 mL per feed) to >500 mL by day 7 postpartum (30–60 mL per feed) (4). Maternal perception of breast fullness on day 3 postpartum suggests normal onset of copious milk production; many women with chronic medical conditions, preterm deliveries, or obstetric complications will have a delay in lactogenesis II or report never feeling breast fullness (4). Full milk supply is defined as >600 mL per day between months 1 and 6 postpartum, with the average individual producing approximately 750 mL (4). Oversupply or hyperlactation is the production of more breast milk per day than is required by the infant for optimal growth, usually >1000 mL per day (4).

Are her medications safe for milk production and her infant?

Most medications are compatible with lactation and are safe for the infant, primarily because there is no risk for teratogenicity, as there is during pregnancy, and exposure to the maternal medication via breast milk is virtually always less than via placental transfer (Table 1 and Figure 1) (5, 6). When in doubt, write “[medication name] LactMed” into your search engine to access free, up-to-date, evidence-based information from the Drugs and Lactation Database (LactMed) of the National Institutes of Health.

Is the patient lactating? If yes, does continued lactation in critical illness lead to issues in management?

Asking about lactation should be just as routine as asking about (or screening for) pregnancy. It is important to continue removing milk regularly by hand or pump or, if possible, allowing the infant to nurse to prevent milk stasis, breast infection, or sepsis. Nephrologists should, at a minimum, know how to contact lactation services and refer to the Academy of Breastfeeding Medicine, Clinical Protocol #35: Supporting Breastfeeding During Maternal or Child Hospitalization for additional information (7).

If she were to receive imaging with contrast or hemodialysis, would she need to discard (“pump and dump”) breast milk?

Imaging with contrast is safe, and there is no need to pump and dump (8). There is not sufficient evidence to support interruption of breastfeeding for patients undergoing peritoneal dialysis or hemodialysis; expressing breast milk immediately before dialysis and saving it to mix with post-dialysis breast milk can be suggested. For the first 6 months postpartum, most women need to remove milk every 2–4 hours, so prioritizing home dialysis to limit maternal-infant separation is key (4).

Should she continue to breastfeed if she needs pulse-dose steroids or different immunosuppressive agents?

Although oral corticosteroids are generally safe (5), injected or intravenously administered high doses of steroids may cause transient suppression of milk production (4). Patients can be advised to pump and save breast milk to mix it in small increments with breast milk free of exogenous steroids. Many common maternal immunosuppressants, including biologics, are considered safe for the infant (Figure 1 and Table 1) (5, 6).