Breastfeeding trajectories for preterm infants over the first 6 months of life in England 2010-2020: surveys using large representative birth samples.

Background: Breastmilk is the optimal source of nutrition for infants, particularly preterm infants. Preterm infants face unique feeding challenges and these change with the birth gestation of the infant. Preterm infants' feeding outcomes may have been affected differently than term infants by the SARS-CoV-2 pandemic. The objective of this study was to describe the feeding trajectories of preterm infants in the first 6 months of life compared with term infants and compare these across prepandemic and pandemic periods.

Methods: Data were extracted from the 2010 UK Infant Feeding Survey and the English National Maternity Surveys of 2018 and 2020. Original survey weights were used. Infants were divided by gestation into term (37+0 to 42+6 weeks' postmenstrual age), late preterm (34+0 to 36+6 weeks' postmenstrual age) and a lower gestation group (23+0 to 33+6 weeks' postmenstrual age). Modified Poisson regression, log-rank tests and survival curves were used to analyse feeding outcomes by gestational age.

Results: Late preterm infants had lower adjusted relative risk (aRR) of exclusive breastmilk at 6 weeks of age compared with term infants in 2010 and 2020 but not in 2018. In 2010, aRR was 0.47 (95% CI 0.29 to 0.74), in 2018 aRR was 0.86 (95% CI 0.67 to 1.10) and in 2020 aRR was 0.57 (95% CI 0.41 to 0.81). There was no evidence of differences in feeding outcomes between infants born less than 34 weeks' postmenstrual age and term infants.

Conclusion: Late preterm infants had worse breastfeeding outcomes than term infants in 2010, but the inequity was reduced or eliminated in 2018. In 2020, during the early SARS-CoV-2 pandemic, the inequity had re-emerged. Late preterm infants appear to be a particularly vulnerable population in relation to breast feeding. In future emergencies and natural disasters, late preterm infants should receive additional focus and resources to support breastfeeding establishment.