Weight change in the term baby in the first 2 weeks of life

Midwives once used serial weighing to highlight lactation problems, but this is now discouraged for the fear of undermining maternal confidence.

To explore weight changes in healthy newborn term babies, to gain information to aid interpretation of such measurements and to construct a centile chart for those exclusively breastfed during the first 2 weeks.

Two hundred ninety-nine mothers weighed their baby daily using the same electronic scales. In 46 cases, three or more consecutive measurements were omitted leaving 253 series to evaluate, of which 111 were exclusively breastfed.

Breastfed babies lost a mean 6.4% of birthweight (95% CI: 5.5-7.3%) before starting to gain, and 54% took more than 8 days to regain birthweight. Artificially fed babies lost less (3.7%, 95% CI: 2.7-4.7%), but 39% had not regained their birthweight by 8 days. Once birthweight was regained, average gain was about 1% of birthweight per day in both breast- and artificially-fed babies. Measurements less than 5 days apart predicted average weight gain poorly.

Feeding problems should be considered if weight is not increasing by 6 days, but some healthy babies take 17 days to regain their birthweight.