Breast Milk Expression and Related Factors Judith Labiner-Wolfe, 1 PhD; Cunlin Wang, 1 MD, PhD; Sara Fein, 1 PhD; and Katherine Shealy, 2 MPH, IBCLC, RLC 1 Food and Drug Administration 2 Centers for Disease Control and Prevention

Issue The availability of breast pumps has changed dramatically over the past 10 years Milk expression may be an important practice to aid mothers in reaching their breastfeeding goals How, when and why mothers express breast milk has not been well-studied

Objectives Describe when mothers initiate breast milk expression Describe the methods used to express breast milk Determine the prevalence of breast milk expression Identify factors associated with breast milk expression Describe the reasons mothers express breast milk Calculate the mean frequency and volume of breast milk expressed

Data Detailed questions about milk expression were asked on the 2, 5, and 7 month questionnaires Used actual age of the infant when mother completed each questionnaire to set age categories months months months

Initiation of breast milk expression Many mothers initiated milk expression in the early postpartum 85% of 1,541 breastfeeding mothers had expressed milk by 4.5 months More than half of the 1,308 mothers who would express milk by 4.5 months started doing so in their infant’s first week

Methods used to express milk

Number of breast pumps used months 34% used more than one pump months 24% used more than one pump months 17% used more than one pump

Prevalence of milk expression (past 2 weeks)

Factors associated with milk expression Increased likelihood of any milk expression at months Mother employed Higher family income Living in Midwest or South vs. West Mother received pain medication during delivery Mother had no experience breastfeeding other children

Reasons mothers express milk Reasons mothers of infants months expressed milk in the past 2 weeks (n=1022) Get milk for someone else to feed baby: 69% Emergency supply: 43% Relieve engorgement: 42% Increase milk supply: 33% When mom doesn’t want to breastfeed: 31% Keep up supply when baby could not nurse: 27%

Reasons mothers express milk Reasons mothers of infants months expressed milk in the past 2 weeks (n=652) Get milk for someone else to feed baby: 70% Emergency supply: 35% Mix with cereal: 35% Keep up supply when baby could not nurse: 33% Relieve engorgement: 32% Increase milk supply: 27% When mom doesn’t want to breastfeed: 24%

Reasons mothers express milk Reasons mothers of infants months expressed milk in the past 2 weeks (n=422) Get milk for someone else to feed baby: 63% Mix with cereal: 39% Emergency supply: 37% Relieve engorgement: 34% Keep up supply when baby could not nurse: 32% Increase milk supply: 23% When mom doesn’t want to breastfeed: 18%

Mean frequency and volume Number of times and ounces pumped in the past 2 weeks months (n=1030): times; 4.15 oz months (n=649): times; 4.46 oz months (n=426): 12.10; 4.58 oz

Factors associated with volume Few factors were associated with increased volume An exception is mother employed

Factors associated with frequency Several factors were associated with increased frequency Mother employed Higher family income Mother embarrassed breastfeeding in public Mothers’ prenatal intent to breastfeed <1 yr vs. longer Mother had no experience breastfeeding Mother received pain medication during delivery

Conclusions Most breastfeeding mothers expressed milk early in their infant’s life Electric pumps were the most common method for expressing milk

Conclusions Percentages expressing milk on a regular schedule were constant over time Mothers were more likely to express milk when they were employed and did not have previous experience breastfeeding

Conclusions Many reasons mothers reported for expressing milk are commonly understood barriers to continued breastfeeding One lead reason mothers expressed milk was to have an emergency supply

Conclusions The frequency and volume of milk expression was constant as the infant ages Embarrassment breastfeeding in public and no previous experience breastfeeding other children were associated with expressing milk more frequently