The main objectives of the breastfeeding class evaluation were to assess:
The evaluation used a one-group pretest-posttest design. While this design is not sufficient for tests of causal hypotheses9, the very short interval between pre-and post-tests rules out several threats to the internal validity of results (history, statistical regression and maturation), and thus a number of plausible alternative interpretations. However, in the absence of a comparison group, it is not possible to know that outcomes are attributable to the breastfeeding course.
The sample consisted of 162 participant mothers and 100 partners or coaches recruited from 22 breastfeeding classes held over a one-year period in 2005-06.
There were three measures for data collection:
There were three versions of the knowledge questionnaire for the mother, and, if applicable, for the coach or partner. In addition, a telephone call was made to participating mothers two weeks after their expected date of delivery. This was done to determine the infant's actual date of birth and the date of discharge, in order to allow the postpartum call to take place six weeks after discharge.
The initial questionnaire, before the class, was designed to assess the participants' baseline breastfeeding knowledge level. The questionnaire at the end of the class was intended to assess participants' knowledge of breastfeeding after the class, their perceptions of the importance of, and their confidence in, breastfeeding, and their satisfaction with the class. The six week interview asked mothers about their breastfeeding status, experience and supports, and their appraisal of the breastfeeding class in light of their experience.
Participation in the evaluation was voluntary and confidential. The letter of information is presented in Appendix A. Two-week and six-week calls were made only to mothers who consented to follow-up. Mothers and partners or coaches withholding consent to participate in the evaluation remained participants in the class. In addition, mothers were given a card in a stamped, self-addressed envelope to return to KFL&A Public Health if they decided that they did not wish to be contacted by telephone. If a mother experienced an adverse birth event, this card enabled her to withdraw from the evaluation without a potentially upsetting telephone call. The evaluation protocol was reviewed and approved by the Queen's University Health Sciences and Affiliated Hospitals Research Ethics Board.
The questionnaire items that assessed breastfeeding knowledge were based on material presented in the class. The pre-test and post-test were piloted with the participants of four breastfeeding classes to ensure that the questions were understandable, yet difficult enough to allow changes in knowledge to be observed.
Each knowledge portion of the questionnaires consisted of ten true-false items; five items were common to both the pre-test and post-test forms, while five were unique to each form. The content and level of difficulty of the two forms were designed to be roughly equivalent. Half of the classes received one form as a pre-test and the other as a post-test, and the order was reversed for the other half of the classes, in order to avoid pre-test effect.
In consultation with program staff, questions were developed to assess other outcomes of the breastfeeding class. Revisions were made to these questions, based on feedback from pilot participants in four classes. The final questions assessed mothers'confidence in their ability to breastfeed, partners' or coaches' ability to support the breastfeeding mother, and perceptions of the importance of breastfeeding and satisfaction with the class. The initial pre- and post-class questionnaires are included in Appendix B, and the six-week postpartum questionnaire is attached as Appendix C.
Participants were asked to sign a consent form at the beginning of the class indicating their willingness to participate in the evaluation. Mothers were asked to provide alternate contact information in case Public Health staff had difficulty reaching them for follow-up. All participants were given a card to mail in if they did not want to be contacted for the follow- up telephone calls.
Mothers and coaches or partners completed the initial questionnaires before and after the class. Calls for the interview at six weeks postpartum began as near as possible to this date. Up to 8 call attempts were made to reach participants.
Wilcoxon signed ranks tests were carried out on both mothers' and their partners' pre and post scores on breastfeeding knowledge, and on their ratings of the importance of breastfeeding and confidence in ability to breastfeed. For the 6-week postpartum survey data, frequencies were run for all variables. A chi-square analyses examined the association between breastfeeding status and ratings of breastfeeding confidence.