Antenatal peer support workers and initiation of breast feeding: cluster randomised controlled trial

Intervention

The intervention was a new community based antenatal breastfeeding service using peer support workers developed by the primary care trust mainly to increase its rate of initiation of breast feeding, which was lower than many primary care trusts in the UK. The service was in addition to usual antenatal care provided by midwives. It comprised 11 peer support workers for breast feeding who were recruited, as far as possible, to be peers of the women in the clinics in which they worked on the basis of ethnicity and language and to have had personal successful breastfeeding experience of several months’ duration. They were trained by the infant feeding team within the primary care trust, which included specialist midwives and other health workers. The training was daily over eight weeks, based on the Unicef baby friendly breastfeeding management course, and addressed cultural beliefs and barriers appropriate to the local population. The peer support workers were oriented into the environment of the community antenatal service, and worked in their positions for three months. When we considered that the support service was fully operational the evaluation procedures were piloted for a month. The planned level of contact by a peer support worker was to make an initial introduction in the antenatal clinic followed by a minimum of two contacts, one at 24-28 weeks’ gestation and the other around 36 weeks’ gestation. The first of these could directly follow the initial introduction, but at least one contact was to be in the home. The duration of each support session was based on need. The peer support worker followed up women who initiated breast feeding to give postnatal support. The purpose of the antenatal consultations was to provide advice and information on the benefits of breast feeding and to be able to support women with particular cultural barriers or concerns. The peer support workers were managed by the infant feeding team but were also responsible to, and worked with, the midwives in the antenatal clinics.

All pregnant women registered with practices in the primary care trust randomised to provide the new peer support worker service were offered contact with a peer support worker. The peer support workers kept a log of women who reached 24-28 weeks’ gestation, noting those who refused support and why. For those women who had a support session the peer support worker recorded any history of infant feeding and plans for feeding before giving advice, when and where each session took place, and issues covered. Women in the control clusters received standard antenatal care, which included usual information and advice from midwives on breast feeding, without input from community peer support workers. Intrapartum and early postpartum hospital care was the same for women in both intervention and control groups, which may have included advice and support from hospital (rather than community) midwives and peer support workers, the numbers of peer support workers having increased as part of the overall breastfeeding initiative of the primary care trust.

Outcome assessment

The primary outcome was initiation of breast feeding, defined as a positive response to whether the infant had had breast milk either at the time of delivery or by the time of hospital discharge, as recorded in the hospital records. Data were obtained anonymously from the three main hospitals that provide maternity care for women in the primary care trust for deliveries during the study period of 1 February to 31 July 2007. We did not include the few women who delivered in other hospitals or at home in the assessment of outcome, although those from intervention clusters would have been offered contact with a peer support worker antenatally. From hospital records we obtained information on general practice identifying code, date of delivery, age, parity, mode of delivery, ethnic group, and Townsend deprivation score. As data on outcome were supplied to the research team in an anonymised format the local research ethics committee approved that individual patient consent was not required.

Sample size

At the time the peer support worker service was planned in 2005, the initiation rate for breast feeding within the primary care trust was 58% and about 6000 deliveries took place per year. Members of the primary care trust considered that full and continued implementation of the service would be worthwhile with a 6% increase in initiation of breast feeding. To estimate the sample size for a cluster randomised trial we needed an estimate of the degree of clustering at the practice level, which was available from a previous randomised trial of postnatal care.¹⁰ Using the approach of a previous study,¹¹ and taking the interpractice correlation coefficient to be 0.005 as indicated in that trial, we inflated the sample size by 2.45 times from a non-cluster randomised trial. We therefore required a total of just under 3000 women to estimate a 6% absolute difference in initiation of breast feeding with a power (1-β) of 90%.

Primary outcome

Initiation rates for breast feeding did not differ between intervention and control groups; 69.0% and 68.1%. The cluster adjusted odds ratio was 1.11 (95% confidence interval 0.87 to 1.43, P=0.40, interpractice correlation coefficient 0.07; table 2​2).). These rates excluded women with missing data on initiation of breast feeding. If missing data were assumed to be for women who had not initiated breast feeding then initiation rates would be 65.5% and 65.4%. Multiple imputation techniques provided a similar result to the analysis using complete data: cluster adjusted odds ratio 1.10 (0.86 to 1.42, P=0.44).

Effects of mothers’ characteristics

Initiation of breast feeding varied according to several sociodemographic and delivery characteristics (table 3​3).). Initiation was lower in Heartlands Hospital, younger and older women, those who had a Caesarean section, and multiparous women. Differences were large according to ethnic group, with the lowest initiation of breast feeding among white British women and the highest among African-Caribbean women. Substantial variation was found among Asian ethnic groups, with the lowest initiation of breast feeding among Bangladeshi women and the highest among women of Indian (subcontinent) origin. No difference was found for deprivation score, but 70% of the sample was in the lowest 10th. Multivariable analysis with adjustment for cluster showed that being from an ethnic minority group compared with being white British, and being primiparous were independently associated with an increased likelihood of initiating breast feeding (table 4​4).). Accounting for confounding factors in the multivariable model, however, had little effect on the primary outcome.

Strengths and weaknesses of the study

Our trial is larger than any other of the peer support trials that reported on initiation of breast feeding we found through a systematic search of the literature. The coverage of women was high but the intensity of the peer contact may be a limitation because this was less than planned. The service was universal, with 80% of women offered support and 74% taking up the offer. Two antenatal sessions were planned but these were attended by only 42% of women. In addition one session should have been at home but this rarely took place, and many sessions were short. It is possible that more contacts took place than were recorded, since a parallel qualitative study found that some peer support workers had difficulties in completing the activity logs, which is perhaps unsurprising given that the peer support workers were selected for their peer characteristics rather than administrative experience. Moreover, despite recruiting peer support workers who were ethnically and linguistically appropriate for the local population, exact matches for the large number of ethnic and linguistic groups were not possible.

Another limitation of the trial could be that data on initiation of breast feeding were obtained from the routinely collected maternity records, which are not generally considered to be as error free as data specifically collected by a research team. However, this allowed a low loss to follow-up, at only 5%, and the quality of the data was similar across trial groups. Moreover, primary care trusts in the UK use such hospital based data to assess their targets for initiation of breast feeding.

Although the study groups did not differ in initiation rates a 10% absolute increase occurred from the rate when the primary care trust had decided to set up the new service. During this period other initiatives to increase initiation of breast feeding, especially its recording, were also implemented. This included increased hospital based peer support and much closer scrutiny and subsequent changes to the quality of the data given to primary care trusts by the hospitals to inform initiation rates. This illustrates the necessity of robust evaluation using a randomised controlled design rather than studies with a before and after design.

Meaning of the study

The lack of effect found from the predominately antenatal clinic based peer support worker service evaluated in this study suggests that such a service should not be adopted as standard care. If the service had included more home based contact it might have had an effect, although in the two other UK trials^{8 14} peer support was entirely home based and no improvement occurred in any breastfeeding outcomes. The service might have needed to be more intensive, and in the other UK trials contact antenatally comprised only one visit for most women, fewer than in the present trial. In the two US trials, however, substantial improvements in initiation of breast feeding were shown, with only one and three antenatal contacts alongside peer support in hospital.^{15 16} Perhaps the amount of advice on breast feeding and support already provided routinely in antenatal clinics in the UK allows for little additional gain from other interventions to increase initiation rates. A more intensive universal home based service would require greater investment. Rather than providing this, peer support might be more effective if targeted at specific groups, such as those women not planning to breast feed, which was around 40% of participants in this study, or those for whom routine advice on breast feeding is less accessible because of linguistic difficulties. Future service interventions, however, must be subject to proper evaluation.