The idea that a bottle of formula can make a baby sleep longer is bandied about pretty regularly. New parents, the notoriously sleep-deprived, might easily find themselves lured into trying formula by the promise of a few extra hours of shut-eye. More accurately: I've met new parents who'd have sold their souls for a few extra minutes of shut-eye, which is why the myth that formula feeding can provide that sleep is so damaging.
A study publishied in the November, 2010 issue of Pediatrics lays this myth to rest, once and for all. The study found no measureable difference between breastfeeding mothers, formula feeding mothers and mothers who fed by both breast and bottle in terms of actual recorded minutes of sleep or in self-reported sleep quality or fatigue.
The study cited the possibility that breastfeeding mothers may wake less fully during night feeds (no lights to turn on or bottles to prepare in the kitchen!) and that they may return to sleep more quickly after (or even during) feedings due to the relaxing hormone soup their bodies release during nursing.
So, the next time a well-meaning advisor tells you that formula will help your baby sleep longer, you can smile, nod and know better.
Infant Feeding Methods and Maternal Sleep and Daytime Functioning
Pediatrics, Nov 2010; doi:10.1542/peds.2010-1269d