TOPLINE:

Female newborns had higher odds of not receiving vitamin K prophylaxis than male newborns, with parental refusal rates increasing between 2018 and 2025. Among newborns whose parents declined vitamin K prophylaxis, more than 80% also did not receive hepatitis B vaccine (HBV).

METHODOLOGY:

• Researchers conducted a retrospective cohort study examining the association between newborn sex and parental acceptance of vitamin K prophylaxis and HBV at three centers of the University of Pennsylvania health system from 2018 to 2025.
• A total of 93,163 newborns (born at ≥ 35 weeks’ gestation) eligible for well-newborn care were included in the analysis.
• Data on maternal and newborn characteristics and on vitamin K prophylaxis and HBV administration status during the hospital stay were extracted from the electronic medical record.

TAKEAWAY:

• Overall, 777 newborns did not receive vitamin K prophylaxis (8.3 per 1000 births) and 9400 did not receive HBV (100.9 per 1000 births). Among the newborns whose parents declined vitamin K prophylaxis, 83% also did not receive HBV.
• Female sex was associated with higher odds of nonreceipt of vitamin K prophylaxis (adjusted odds ratio [aOR], 2.03; P < .001) and HBV (aOR, 1.06; P = .02) than male sex.
• Among female newborns, refusal rates of vitamin K prophylaxis increased yearly by 1.37 newborns per 1000 female births (P = .01), and among male newborns, the rates increased annually by 0.75 newborns per 1000 male births (P = .02).
• The rates of HBV refusal increased annually by 10.3 newborns per 1000 female births (P = .02) and 11.0 newborns per 1000 male births (P = .008).

IN PRACTICE:

“Innovative strategies are required to reduce disparities in VK [vitamin K] prophylaxis and HBV administration and limit life-threatening morbidity among female newborns,” the authors wrote.

SOURCE:

The study was led by Sarah A. Coggins, MD, MSCE, of the Division of Neonatology at the Children’s Hospital of Philadelphia, Philadelphia. It was published online on June 15, 2026, as a research letter in JAMA Network Open.

LIMITATIONS:

The analysis was done within one health system, which may limit generalizability to other settings. The link between vaccination status and morbidities after the hospital stay was not assessed.

DISCLOSURES:

One author disclosed that she was supported by a Eunice Kennedy Shriver National Institute of Child Health and Human Development grant. Another author disclosed serving as the Chair of the American Academy of Pediatrics Committee on Fetus and Newborn.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.