Genealogy of breastfeeding

Abstract

Decline and resurgence of breastfeeding (BF) characterized last century. Several factors influencing BF outcome were identified. Despite the huge literature on BF, no data on its matrilineal transmission are available. BF practice was prospectively followed in 2546 Italian mothers. Lactation and BF outcome were related, besides to known factors interfering with BF, to the occurrence of previous maternal and paternal BF. Recalls of grandmaternal and grand-grandmaternal BF behaviours allowed the construction of familiar pedigrees of BF across three generations. Having been breastfed was the strongest factor addressing successful BF establishment (odds ratio (OR) 9.33; 95% confidence interval (CI) 7.40-11.84; p < 0.0001) and BF duration (at 6 months: OR 3.79; 95% CI 3.11-4.64; p < 0.0001). The hazard ratio for breastfed vs non-breastfed mothers was 0.46 (95% CI 0.41-0.50; log-rank p < 0.0001). The rate of BF failures was fivefold higher in non-breastfed mothers, mostly occurring during lactogenesis when the let-down reflex becomes essential.

Conclusion: At any generation, mothers are likely to have daughters repeating their BF experience. Differently from the intergenerational effects of environmental factors responsible for the BF secular trend, this trait is transgenerationally transmitted and reversible, with temporal and clinical features of lactation failure. Accordingly, we speculate that epigenetic mechanisms might alter offspring's oxytocinergic receptor signalling.

What is known: Several cultural and socio-demographic factors are known to influence breastfeeding outcome. The generational effects of breastfeeding itself have not been investigated so far.

What is new: Maternal breastfeeding is the most important factor addressing daughters' breastfeeding outcome. This behavior is transmitted transgenerationally, with features suggesting epigenetic mechanisms.

Keywords: Breastfeeding; Epigenetics; Lactation; Oxytocin receptor.