There is no research to suggest breastfeeding is more difficult or a later aquired skill than breastfeeding!!!!! The reverse is true. Look up all Paula Meier's research on better O2 sats, etc with breastfeeding vs. bottle feeding. Also C. Lau and R. Schanler study 1997 in Peds or J Peds re timing of aquiring suck-swallow coordination with restrictive flow (read "breastfeeding") vs free flow (read " bottle feeding") devices. All the research in the textbooks re gestational age at which suck- swallow develops is done on a bottle-feeding model. Infants can suck and swallow and coordinate it with breathing at moch less than the "standard" EGA or weight most neonatologists were taught! Bottles down premies, mothers rarely do! Nancy Wight MD, FAAP, IBCLC Neonatologist, San Diego CA