A high proportion of breastfeeding mothers express breast milk at some point. Studies show that approximately 85% and 98% of breastfeeding women in United States (8) and Australia (9) respectively have expressed breast milk at least once. The trend of breast milk expression is also increasing. In a previous Hong Kong study, the proportion of mothers who expressed breast milk at 1 month postpartum increased from 28.6% in 2006-2007 to 41.9% in 2011-2012 (10).
There is no doubt that expressed breast milk feeding provides greater nutritional benefits than infant formula. However, some studies have shown that when compared with direct breastfeeding, feeding expressed breast-milk is associated with adverse health outcomes. Exclusive expressed breast-milk feeding reduces opportunities for skin-to-skin contact and bonding between mother-infant pairs (11) and is associated with increased risk of childhood asthma (12). Expressed breast milk is usually given by bottle, which may diminish the positive effect of direct breast milk feeding. First, there are changes in breast milk components in expressed breast milk (13). Second, the active suckling of the infants during direct breastfeeding can increase the lung volume of infants (14). Furthermore, bottle feeding regardless of the type of milk, is associated with more rapid weight gain during infancy (15) and reduced ability to self-regulate milk intake (16).
Inconsistencies in the effect of expressed breast milk feeding on breastfeeding duration has been found in previous studies. Some studies shows no association between expressed breast milk feeding and breastfeeding duration (17), while others have shown both positive (18) and negative (10, 19, 20) associations. These inconsistencies may be related to limitations in the existing research as the majority of the studies did not specify the frequency and quantities of expressed breast milk feeding (17-20).
Objective: The objectives of this study were to investigate the breast milk expression practices of mothers with healthy term infants and to examine the attitudes and beliefs towards direct breastfeeding and expressed breastmilk feeding.
Methodology: This study will employ a prospective cohort design. The following criteria will be used for screening the eligibility of the study participants: new mothers who are (1) 18 years of age or older; (2) speak Cantonese; (3) Hong Kong Chinese; (4) had a singleton pregnancy; (5); intended to breastfed their baby and (6) had no serious medical or obstetrical complications. Participants will be excluded from the study if they fail to meet these criteria and/or if their baby: (1) is <37 weeks’ gestation, (2) has an Apgar score <8 at five minutes, (3) has a birth weight <2500 grams, (4) has any severe medical conditions or congenital malformations, (5) is placed in the special care baby unit for more than 48 hours after birth, or (6) is admitted to the neonatal intensive care unit at any time after birth.
We plan to recruit approximately 800 mother-infant pairs from the postnatal wards of two public hospitals in Hong Kong. Self-administered questionnaires, which consist of questions on their attitudes and beliefs towards expressed breast milk feeding and direct breastfeeding and their sociodemographic characteristics will be completed by participants in the immediate postpartum period. Infant feeding data in the first 48 hours or until hospital discharge will be recorded as well as maternal and neonatal health histories.
Participants will be followed up by telephone at 1.5, 3 and 6 months postpartum or until breastfeeding is stopped. Infant feeding patterns, including the amount and type of all milk feeding (direct breastfeeding, expressed breast milk feeds, and infant formula) provided to the infant in the preceding 24-hours, breast milk expression practices and breastfeeding problems experienced will be assessed in the telephone follow-up. Weaning data, including the total duration of any and exclusive breastfeeding, the total duration of expressed breast milk feeding, and the reasons for weaning (if applicable) will be assessed. Attitudes and beliefs towards direct breastfeeding and expressed breast milk feeding will be measured using modified items from the Iowa Infant Feeding Attitude Scale (IIFAS). Items from the IIFAS are measured on a five-point Likert scale with responses ranging from Strongly Agree to Strongly Disagree.
Informed written consents will be obtained from all participants. Ethical approvals has been obtained from the Institutional Review Boards of the University of Hong Kong/ Hospital Authority Hong Kong West Clusters and the participating study hospitals.
Results: Descriptive statistics will be used to summarize the sample characteristics and for determining mean IIFAS scores. Breast milk expression patterns will be described and logistic regression will be used to identify factors associated with any and exclusive expressed milk feeding.
Conclusion: There have been little evidence on the effect of breast milk expression on breastfeeding duration. Given the increasing prevalence of breast milk expression and limited evidence about its effects, the proposed study will contribute substantial new information about current breast milk expression and breast milk feeding practices. This study will help to allocate educational resources to prevent early breastfeeding problems and provide adequate breastfeeding support.
Funding:
This research is supported by the seed funding for basic research from the University of Hong Kong.
See more of: Invited Posters