Very preterm gestation and breastmilk cytokine content during the first month of lactation

High susceptibility to infection and deficient cytokine production in newborns make breastmilk beneficial, especially for very preterm-born infants. This study was conducted to identify the association between very preterm gestation and levels of pro- and anti-inflammatory cytokines in transitional and mature breastmilk during the first month of lactation after adjustment for mode of delivery and parity.

Four samples of breastmilk (6-8, 13-15, 20-22, and 27-29 days) were collected from each mother after term or very preterm delivery at gestational age of less than 32 weeks. We measured the concentration of interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-13, and tumor necrosis factor α (TNF-α) in the milk samples using a multiplex biometric immunoassay.

Fifteen mothers of very preterm infants and five term-born infants provided 80 samples of breastmilk. We found that delivery at very preterm gestation was linked with lower IL-8 (687 ± 208 pg/dL, p < 0.003) and higher IL-10 (27.8 ± 14.2 pg/dL, p < 0.01) levels in transitional breastmilk. Significantly decreased IL-8 levels were also seen in mature preterm milk samples. Cesarean delivery was associated with increased breastmilk TNF-α and IL-6 (p < 0.01-0.05), but gestational age was not.

Very preterm gestation does not substantially impact the cytokine content of breastmilk during the first month of lactation, which can be beneficial for the regional and systemic immune response of the very preterm infant with confirmed impairment of innate and adaptive immunity.