Never Breastfed | Early Formula ^{*} | Postponed Formula ^{†} | Never Formula ^{‡} | P Value | ||
---|---|---|---|---|---|---|

Percent (N) | Before | 28.9 (281) | 54.7 (530) | 12.8 (124) | 3.8 (37) | .001 |

After | 18.9 (162) | 26.5 (227) | 45.4 (389) | 9.2 (79) | ||

Mean duration of breastfeeding (days) ^{‖} | Before | — | 90.4 (±120.7) | 119.4 (±125.7) | 183.7 (±159.4) | .0001^{§} |

After | — | 83.0 (±118.4) | 145.1 (±149.4) | 205.0 (±168.9) | .0001^{§} |

↵* Consists of children who received some breast milk but were also fed formula prior to discharge following the delivery.

↵† Consists of breastfed infants who received formula at some point, but starting after discharge from the hospital. Mean age at introducing formula in those who postponed formula was 88.3 (±120.8) days before and 97.0 (±128.5) days after the intervention.

↵‡ Consists of infants who were never reported to have received formula.

↵§

*P*value for difference between the three groups at each time, after excluding the never breastfed group.↵‖ Mean duration of breastfeeding is taken from the last date at which infants were known to have been breastfed, up to the age of 1.5 years when the chart review was terminated. This method undoubtedly underestimates the duration of breastfeeding since some infants breastfed beyond 1.5 years, particularly among the group which was never given formula.