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Table 1 Measures of independent variables*+

From: Determinants of breastfeeding initiation and cessation among employed mothers: a prospective cohort study

Independent variables (Coding) Item description, reference and data source
Age (years) Abstracted from the medical chart by maternity nurses and calculated from date of birth. (Continuous Variable; Range: 18–45)
Race (1 = non-white, 0 = white) Adapted from Census 2000 [24]*
Educational Status
(High School Education or less = 1; else = 0; 2-year College/Technical = 1; else = 0; College Graduate = 1; else = 0; Graduate School = reference)
Adapted from the National Health Interview Survey [25]*
Marital Status
(Single = 1; else = 0; Partnered = 1; else = 0; Married = reference)
Adapted from National Health Interview Survey [25]+
Parity (1 = Primipara; 0 = else) Adapted from National Health Interview Survey [25]*
Annual Household Income ($) Adapted from National Health Interview Survey [25]*
Prenatal Smoking
(1 = no; 0 = yes)
“Did you smoke cigarettes during this pregnancy?”, item adapted from Palermo; [26]*
Pre-pregnancy Health
(1 = poor/fair, 2 = good, 3 = very good, 4 = excellent)
“How would you rate your health in general before this pregnancy?”*
Prenatal Moods
(1 = no; 0 = yes)
“During this pregnancy did you ever have a problem with your mood, such as feeling depressed or anxious?”, item taken from McGovern et al.; [23]*
Breastfeeding by Family and Friends
(1 = no; 0 = yes)
“To the best of your knowledge, did any of your family or close friends breastfeed?” +
Breastfeeding Problems
(1 = yes; 0 = no)
“Have either you or your baby had any problems or conditions that may prevent you from breastfeeding?” * Women who answered “yes” received a follow up question: “What is the nature of the problem or condition?”*
Delivery Hospital
(North Memorial = 1; else = 0; St. Joseph = 1; else = 0; St. John = reference)
Occupational Classification
(Blue Collar/Service = 1; else = 0; Professional = 1; else = 0; Clerical = reference)
Taken from US Census [27]+
Leave Status
(1 = working, 0 = on leave from work). Time-dependent covariate in survival models. Subjects were coded as 0 until the day they returned to work at which point they were coded as 1.
“Are you: 1. On leave (including part-time leave)? 2. Working again (whether from home or at the office)?” Item adapted from Cantor et al. [28] and asked at each of the three postpartum periods.
Employer Provides Paid Leave Policy (1 = yes, 0 = no) “Are you eligible for any PAID time away from work with this employer (e.g., vacation or sick time, PTO or maternity/disability leave)?”*
Longest Paid Leave Possible by Empl
oyer Policy (days)
“Assume you hadn’t used any sick leave or vacation this year. What is the longest leave you could have taken before and after childbirth and still received at least some pay?”+ (Continuous Variable; Range: 0–273)
Prenatal Hours Worked/Week (hrs) Average work hours in the past 12 months* (Continuous Variable; Range: 20–80)
Prenatal Job Stress
(two item summary score of 2 = almost never to 10 almost always)
Items taken from Mardburg et al.; [29] “How often do you have too much to do? How often do you experience stress from your job?” * (Continuous Variable; Range: 0–8)
Supervisor Support
(1 = Somewhat/Strongly disagree, 0 = Somewhat/Strongly agree)
Adapted from Bond et al.; [30] item asked: “My supervisor has been helpful to me when I have had to take care of personal or family matters.”*+
Coworker Support
(1 = Somewhat/Strongly disagree, 0 = Somewhat/Strongly agree)
Adapted from Bond et al.; [30] item asked: “My coworkers have been supportive of me when I had to take care of personal or family matters.”*+
  1. Note. This table is adapted from table 1 in an earlier publication [22]
  2. *The asterisk denotes self report data collected in-person at enrollment in the hospital
  3. +The cross denotes self report data collected by telephone at the six-week interview
  4. **Personal and Perinatal factors were considered confounders (control variables) in logistic and survival analyses