Participants

The study was undertaken at one government hospital in Hong Kong that had active breastfeeding support and had recently started a PC volunteer programme. Mothers were eligible for inclusion in the study if they were Cantonese-speakers, healthy and had had a vaginal delivery of a full term healthy infant. It was required that mothers planned to stay in Hong Kong for six months postpartum, and that they expressed an intention to breastfeed upon admission to the postnatal unit.

Intervention

As part of the hospital's PC volunteer programme, mothers were visited by a PC postpartum on an ad hoc basis. The PC would provide mothers with information on the benefits of exclusive breastfeeding, breastfeeding during illness, basic lactation anatomy and physiology, positioning and "latching-on", common myths, problems and solutions, healthy breastfeeding patterns, maternal concerns, milk expression and storage, and sources of social and community support. If a mother was subsequently recruited into the PC intervention group, she would in addition receive seven regular telephone consultations from a PC (at 24 hours, four days, one week, two weeks, one month, two months and four months post discharge). These contacts were discontinued at any time if the mother decided to completely stop breastfeeding her infant. The PCs were allowed to provide more frequent telephone support if necessary. The control group mothers would not receive a PC visit or any phone contacts. They would receive the usual postnatal care and breastfeeding advice which included antenatal education.

Objectives

This study was designed to assess whether a programme involving a postpartum PC hospital visit followed by PC telephone support after discharge could be an effective strategy to promote breastfeeding in Hong Kong by increasing the duration and exclusivity of breastfeeding.

Sample size

A total of 200 mothers were recruited into a PC intervention group (n = 100) and control group (n = 100). The hospital had information on the rate of any breastfeeding rate at discharge, and at one week and one month after discharge. These data showed that in 2001, 46% of mothers who initiated breastfeeding were continuing to mainly breastfeed at one month. A sample of 100 subjects in each group would demonstrate an increase in this "mainly breastfeeding" rate from 46% (control group) to 67% (intervention group) with alpha [confidence level] = 0.05 and power of 80%. We had assumed a more modest benefit of our PC intervention than those reported by Morrow (12% controls and 67% of a six-visit intervention group were exclusively breastfeeding at three months) and Haider (6% controls and 70% of a 15-visit intervention group were exclusively breastfeeding at five months) as these two studies had home visits as part of the intervention [7, 8].

Randomisation

The hospital's PC visiting programme was conducted on an ad hoc basis at a time convenient to the PC. In view of the ad hoc visiting schedule of the PCs it was decided for recruitment purposes to allocate eligible mothers on an alternating basis, and subject to bed availability, to one of two ward areas: a PC ward area or a control ward area. The PCs were asked to only see mothers allocated to the PC ward area during the study period. Although this was done to avoid the potential influence of placing a control mother next to mother receiving PC advice, the strategy had the effect of preventing a true randomisation of mothers as enrolment occurred after allocation to these ward areas. All potentially eligible mothers were screened by one of us (Esther Wong) on the day of discharge. PC group mothers needed to have had at least one PC hospital visit and they were recruited even if they had given up breastfeeding prior to discharge to avoid over-estimating any potential benefit of the PC intervention. As the numbers of potential control group mothers exceeded the number of potential PC mothers, computer generated random number lists were used for the selection of control mothers. The recruitment process is summarised in Figure 1.

Data collection

Recruitment data were collected through a structured interview, after obtaining signed informed consent and included information on mother's obstetric and breastfeeding history, current feeding method, preparation for breastfeeding, lactation problems, breastfeeding support network, breastfeeding duration plan, breastfeeding confidence level, breastfeeding knowledge (pre-test), information on hospital practice postpartum related to the Ten Steps of the Baby Friendly Hospital Initiative, demographic information and infant formula supplementation (if any). Each study mother was followed for 6 months after they returned home. Follow-up interviews, regardless of whether mothers had changed their feeding methods, were scheduled at five days, three months and six months post-discharge. Information collected at these interviews included current feeding practices, feeding problems, baby's health, use of pacifier, infant formula advertisement exposure, and other factors likely to influence feeding choice. The Day five and Month three interviews were telephone interviews. The Month six interview was a face-to-face interview at the mother's local MCHC at the time of a routine visit for immunisation, or was conducted by telephone for those mothers who were not able to meet at the MCHC. Evaluation of the overall breastfeeding experience, evaluation of PC support (for PC group mothers only), breastfeeding knowledge (post-test), questions on breastfeeding plans and detailed questions on infant formula advertisements were only done at the Month six interview. Mothers who stopped breastfeeding at any stage during the study completed a termination questionnaire, which explored factors for early cessation of breastfeeding. Participating PCs completed an evaluation at the end of the study to obtain feedback and comment on the PC programme. The questionnaires were based on those used in the "Perth Aboriginal Breastfeeding Study" in Australia in 2000 [9], and on information related to the "Ten Steps to Successful Breastfeeding" and the "International Code of Marketing of Breast Milk Substitutes". The questionnaires were modified after piloting.

Recruitment of peer counsellors

The PCs were recruited from 21 mothers who participated in the hospital's first PC training course that had been jointly organised with the Baby Friendly Hospital Initiative Hong Kong Association in 2001. These mothers were required to have breastfeeding experience and to be enthusiastic to promote and support other breastfeeding mothers. The 20-hour PC course was conducted by lactation consultants and medical staff with experience in managing breastfeeding problems and involved both lectures and practical sessions on the ward. The course syllabus was based on the 40 hours WHO/UNICEF course for health professionals. After completion of the course, the PCs agreed to provide 80 hours of volunteer work in the hospital. There were 16 of these 21 trained PCs who agreed to participate in the study.

Outcome measures and breastfeeding definitions

The primary outcome measures, breastfeeding duration and exclusivity, were compared between two groups (PC mothers vs. control mothers). As these measures were self-reported by the participating mothers, memory aids and a diary were given to mothers to reduce possible recall bias. To classify breastfeeding during the study, we used Labbok's definitions namely full breastfeeding (exclusive and almost exclusive breastfeeding), partial breastfeeding (high, medium and low) and token breastfeeding [10, 11]. However a further refinement was added by including "predominant breastfeeding" practice as a category between "almost exclusive breastfeeding" and "high partial breastfeeding" categories, where "predominant breastfeeding" was defined as infrequent infant formula feeds in addition to infrequent feeds of water, juice, oral rehydration solution and ritualistic feeds. For the purposes of analysis, two different definitions of exclusive breastfeeding were used: "exclusive breastfeeding since birth" (Labbok's strict definition) which requires that no other liquid or solid (excluding vitamins, minerals and medicines) has been given to the infant since the time of birth [10, 11]; and "current exclusive breastfeeding" (Aarts' definition) that describes the current exclusive breastfeeding status at the time of interview i.e. mother's feeding practice during the 24 hours period prior to the interview. [12].

Ethics approval

The study was approved by the hospital's Ethics Committee and participating mothers were provided with written information about the study and signed informed consent.

Statistical analysis

All data were presented as count, percentage, or mean (standard deviation, SD). Demographic characteristics, breastfeeding characteristics and background information of the infants at the baseline between the PC and control groups were compared using t-test, Mann-Whitney test, Chi-square test or Fisher exact test as appropriate. Time to terminate any breastfeeding was analysed using survival analysis. Survival (continuing to breastfeed) was estimated by Kaplan-Meier method, and the log-rank test was used to compare the overall survival rates (survival curves) between the two groups. Changes in proportions of breastfeeding practice at each of the follow-ups (Day five, Month three, Month six) relative to the baseline between the PC and control groups were assessed using mixed effects logistic regression models. Adjustment was made in the mixed effects logistic regression models for the following confounding factors: previous breastfeeding experience; primiparae or not; working status at baseline. The mixed effects models were fitted using MLwiN (version 2.02, Institute of Education, UK). All other statistical analyses were done using SPSS 11.5 (SPSS INC., Chicago, IL, USA). All statistical tests were two sided and p-value < 0.05 was considered statistically significant.

Participant flow

Within the recruitment period, 15 November 2001 to 30 April 2002, 1587 mothers were admitted to the hospital's postnatal ward (Figure 1). Of the 221 mothers approached in the PC ward area, 178 had had a PC visit making them eligible for recruitment but 78 (44%) refused to participate. In the control ward area 147 mothers were approached and 47 (32%) refused to participate (Figure 1). Common reasons for refusal included mothers were overwhelmed by the birth of the baby, they were unsure about breastfeeding, they anticipated quitting breastfeeding right after discharge, they felt uncomfortable talking about breastfeeding, they did not need any assistance on breastfeeding (mainly in PC group), they did not like to be disturbed by phone interviews, they were in a rush to go home during the discharge period or they were not interested in participating in any research. Two mothers from each study group were lost to follow-up, and one mother from each group withdrew from the study at three months leaving a total of 194 mothers who completed the study (97 in each group) (Figure 1).

Group differences

Outcomes

Ancillary analyses

Kaplan-Meier survival plots of the breastfeeding duration for the two study groups (Figure 2) were not significantly different, log-rank test, p = 0.24. The survival rates of practising any breastfeeding at Month six were 24% with median survival time of 7.7 weeks (95% confidence interval (CI): 6.0, 9.4 weeks) for the PC group and 32% with median survival time of 8.3 weeks (95% CI: 4.6, 12 weeks) for the control group. The proportion of mothers continuing to breastfeed at Day five, Month three and Month six were 87% PC vs 88% Control (p = 0.78), 36% PC vs 41% Control (p = 0.35), and 24% PC vs 32% Control (p = 0.24), respectively (Table 3). None of the 97 PC mothers reported that the peer support was too frequent, over half felt that the overall frequency of the PC support was just adequate, and a few mothers reported that the support was inadequate to help them solve their breastfeeding problems.

Process evaluation

To evaluate the PCs' assessment of the programme, evaluation questionnaires were distributed within two weeks of the trial completion and returned by 11 of the 16 PCs. Telephone consultation time ranged from one minute to 80 minutes. There were three commonly discussed topics related to breastfeeding: insufficient breast milk (82%), frequent feeding (46%), and breastfeeding technique (36%). The main topics related to babies were sleepy baby (46%), information on general baby care (36%) and baby's stool pattern (36%). Key topics related to mothers were breast engorgement and mastitis (46%), emotional problems and handling techniques (18%) and maternal fatigue (18%). Using 10-point rating scales, PCs evaluated the efficiency of the PC program (10 = strongly agree; 1 = strongly disagree). The mean score (± SD) of the overall effectiveness of the program was 8 ± 1.3 (range 6 – 10), with the hospital visits being 8.8 ± 1.2 (range 7 – 10) and the telephone follow-up being 8.2 ± 1.9 (range 4 – 10). The mean score (± SD) for the adequacy of the numbers of scheduled telephone contacts for new breastfeeding mothers was 4.4 ± 3.2 (range 1 – 10). Four PCs rated their confidence at 9, three at 8, three at 7 and one at 5. The mean score (± SD) of the PCs level of enjoyment in supporting breastfeeding mothers through hospital visit and telephone consultations was 7.9 ± 1.4 (range 6 – 10) and 8.1 ± 1.4 (range 6 – 10) respectively. The aspects which participating PCs liked the most were the sense of being supportive (91%) of breastfeeding mothers and their babies, and a sense of satisfaction (73%). In contrast, the aspects which PCs disliked the most were being rejected when offering assistance (36%) and the strong misconceptions about breastfeeding (18%) by some mothers. Although, PCs were encouraged to give their phone numbers to study mothers for two-way contact, only three out of sixteen PCs did so. Although PCs acknowledged that "two-way contact" was likely to be of greatest benefit, most responded that the "one-way contact" model worked best for them in view of time constraints and other commitments. Some PCs noted that it was difficult to keep to the fixed schedule as mothers could not always be contacted. Three PCs responded that they would definitely take part in the program again if it was repeated, seven PCs reported that they probably would do so, and one PC said that she was not sure.