Currently, there is not much evidence to suggest whether the duration of pregnancy has a significant effect on the HMOs present in human breast milk. However, one recent study revealed that total HMOs in preterm breast milk does not differ from that of term breast milk, over the course of lactation.1\r\r\r Kunz C, Meyer C, Collado MC, Geiger L, Garcia-Mantrana I, Berua-Rios B et al. Influence of gestational age, secretor, and Lewis blood group status on the oligosaccharide content of human milk. J Pediatr Gastroenterol Nutr. 2017 May;64(5):789-798.