Approximately 95% of mother-to-child transmission (MTCT) of human T-cell leukemia virus type-1 (HTLV-1) is derived from prolonged breastfeeding, which is a major cause of adult T-cell leukemia (ATL). Exclusive formula feeding (ExFF) is therefore generally used to prevent MTCT. A recent cohort study revealed that 55% of pregnant carriers chose short-term breastfeeding for ≤3 months in Japan. Our meta-analysis showed that there was no significant increase in the risk of MTCT when breastfeeding was carried out for ≤3 months compared with ExFF (pooled relative risk (RR), 0.72; 95% confidence interval (CI), 0.30–1.77), but there was an almost threefold increase in risk when breastfeeding was carried out for up to 6 months (pooled RR, 2.91; 95% CI, 1.69–5.03). Thus, short-term breastfeeding for ≤3 months may be useful in preventing MTCT. Breastmilk is the best nutritional source for infants, and any approach to minimizing MTCT by avoiding or limiting breastfeeding must be balanced against the impact on the child’s health and mother–child bonding. To minimize the need for nutritional interventions, it is necessary to identify factors that predispose children born to carrier mothers to MTCT and thereby predict MTCT development with a high degree of accuracy.

The perception of human T-cell leukemia virus type 1 (HTlV-1) infection as a “silent disease” has recently given way to concern that its presence may be having a variety of effects. HTLV-1 is known to cause adult T-cell leukemia (ATL), an aggressive cancer of peripheral CD4 T cells; however, it is also responsible for HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Most patients develop ATL as a result of HTLV-1 mother-to-child transmission. The primary route of mother-to-child transmission is through the mother’s milk. In the absence of effective drug therapy, total artificial nutrition such as exclusive formula feeding is a reliable means of preventing mother-to-child transmission after birth, except for a small percentage of prenatal infections. A recent study found that the rate of mother-to-child transmission with short-term breastfeeding (within 90 days) did not exceed that of total artificial nutrition. Because these preventive measures are in exchange for the benefits of breastfeeding, clinical applications of antiretroviral drugs and immunotherapy with vaccines and neutralizing antibodies are urgently needed.

Aim: This study aimed to identify the clinical features of infants who were healthy at birth, but developed sudden unexpected collapse and were then diagnosed with cerebral palsy before 5 years of age.Methods: We retrospectively analysed 1182 records from the no‐fault Japan Obstetric Compensation System for Cerebral Palsy database up to 2016. This identified 45 subjects (3.8%) who were subsequently diagnosed with severe cerebral palsy due to sudden unexpected postnatal collapse (SUPC). They were all healthy at birth, based on the criteria of five‐minute Apgar scores of seven or more, with normal umbilical cord blood gases and no need for neonatal resuscitation within five minutes of birth.Results: The median birth weight of the 45 subjects (26 males) was 2770 g (range 2006‐3695 g). Of these, 10 developed SUPC during early skin‐to‐skin contact (SSC). Medical personnel were not present in all 10 cases: nine were being breastfed at the time and eight of the mothers did not notice their infant's abnormal condition until medical staff alerted them.Conclusion: This national study of children with cerebral palsy who appeared healthy at birth found that unsupervised breastfeeding was a common factor in cases of SUPC during early SSC.

The main route of mother-to-child transmission (MTCT) of human T cell leukemia virus type 1 is vertical transmission via breastfeeding. Although the most reliable method for preventing MCTC is exclusive formula feeding (ExFF), short-term breastfeeding (STBF) or frozen–thawed breast milk feeding (FTBMF) has been offered as an alternative method if breastfeeding is strongly desired. The aim of this review was to clarify the pooled risk ratio of MCTC of STBF and FTBMF compared with ExFF. This study was registered with PROSPERO (number 42018087317). A literature search of PubMed, CINAHL, the Cochrane Database, EMBASE, and Japanese databases through September 2018 identified 1979 articles, 10 of which met the inclusion criteria. Finally, 11 articles, including these 10 studies and the report of a recent Japanese national cohort study, were included in the meta-analysis. The pooled relative risks of STBF ≤3 months, STBF ≤6 months, and FTBMF compared with ExFF were 0.72 (95% confidence interval (CI): 0.30–1.77; p = 0.48), 2.91 (95% CI: 1.69–5.03; p = 0.0001), and 1.14 (95% CI: 0.20–6.50; p = 0.88), respectively. This meta-analysis showed no statistical difference in the risk of MTCT between STBF ≤3 months and ExFF, but the risk of MTCT significantly increased in STBF ≤6 months.

Background: Zinc is an essential trace element that is crucial for numerous biological processes, including protein synthesis, antioxidant activity, and bone calcification. Preterm infants are at high risk of zinc deficiency owing to inadequate zinc stores at birth and the rapid decline in zinc concentration in breast milk. This study aimed to evaluate the relationship between zinc concentrations in breast milk and zinc supplementation in preterm infants. Methods: A prospective observational study was conducted at Showa University Hospital, enrolling preterm infants born at less than 32 weeks of gestation or with a birth weight of less than 1800 g. Serum zinc levels, breast milk zinc concentrations, and zinc acetate supplementation were analyzed. Results: The results indicated an inverse correlation between breast milk zinc concentration and the required zinc supplementation dose. Infants receiving high-dose zinc supplementation (≥3 mg/kg/day) had significantly lower breast milk zinc concentrations at 2, 4, and 5 weeks postpartum. Conclusions: These findings highlight the need for individualized zinc monitoring and supplementation strategies to prevent zinc deficiency in preterm infants. Considering the absence of zinc in human milk fortifiers in Japan, aggressive zinc supplementation may be necessary to ensure optimal growth and development.