TABLE 6.

Associations between pumping practices between 1.5 and 4.5 mo postpartum and duration of any HM feeding in mothers in the imputed data set¹

Predictor	Adjustment	HR (95% CI)	P
Pumping frequency as a categorical exposure2
Third quartile compared with less than or equal to the median	Unadjusted	1.49 (1.39, 1.56)	0.0001
Fourth quartile compared with less than or equal to the median	Unadjusted	1.74 (1.58, 1.86)	<0.0001
Third quartile compared with less than or equal to the median	Adjusted3	1.44 (1.37, 1.52)	0.0007
Fourth quartile compared with less than or equal to the median	Adjusted3	1.82 (1.68, 1.93)	<0.0001
Pumping frequency as a continuous exposure4
Pumping episodes in previous 2 wk, n	Unadjusted	1.14 (1.10, 1.18)	<0.0001
Pumping episodes in previous 2 wk, n	Adjusted5	1.148 (1.147, 1.149)	<0.0001

¹HM, human milk.

²In all models, survival analyses were used to compare the survival of HM feeding between the frequency group of interest and the comparison group.

³Full models were adjusted for mothers’ age, marital status (married, widowed, divorced, separated, or never married), the level of education achieved (high school or less, some college, or college or greater), whether they worked at all between 1.5 and 4.5 mo postpartum, and the level of satisfaction with their most-used pump (high compared with low-to-medium).

⁴HRs are presented for an increase of 10 pumping episodes in the previous 2 wk. This number of pumping episodes was chosen to reflect one additional pumping episode per workday for 2 full work weeks.

⁵Full models were adjusted for mothers’ age, marital status (married, widowed, divorced, separated, or never married), the level of education achieved (high school or less, some college, or college or greater), and the level of satisfaction with their most-used pump (high compared with low-to-medium).