Sulfated vitamin D metabolites represent prominent roles in serum and in breastmilk of lactating women.

Background: Concentrations of vitamin D (VitD) and 25-hydroxyvitamin D (25OHD) in breastmilk are low despite the essential role of VitD for normal infant bone development, yet additional metabolic forms of vitamin D may be present. This study evaluates the contribution of sulfated vitamin D metabolites, vitamin D-sulfate (VitD-S) and 25-hydroxyvitamin D-sulfate (25OHD-S) for lactating women and assesses the response to high-dose VitD supplementation.

Methods: Serum and breastmilk were measured before and after 28 days with 5000 IU/day VitD intake in 20 lactating women.

Infant and Maternal Vitamin D Supplementation: Clinician Perspectives and Practices.

Introduction: Rates of infant vitamin D supplementation fall short of guideline recommendations. We explored this discrepancy from the clinician perspective as they advise and affect this important intervention to prevent rickets. We compared infant and high-dose maternal vitamin D supplementation prescribing attitudes and practices between infant-only clinicians (IC) and clinicians who care for mothers and infants (MIC).

Initiation of Gender-Affirming Testosterone Therapy in a Lactating Transgender Man.

Introduction: Transgender and gender diverse individuals may choose to provide their infants with human milk. Lactating transgender men may experience gender dysphoria and desire to initiate or reinitiate gender-affirming testosterone therapy. However, there is limited safety data regarding use of testosterone during lactation.