Abstract: We have included data from 27 randomised trials involving 12,256 women. All of the trials examined telephone support versus usual care (no additional telephone support). We did not identify any trials comparing different modes of telephone support (for example, text messaging versus one-to-one calls). All but one of the trials were carried out in high-resource settings. The majority of studies examined support provided via telephone conversations between women and health professionals although a small number of trials included telephone support from peers. In two trials women received automated text messages. Many of the interventions aimed to address specific health problems and collected data on behavioural outcomes such as smoking cessation and relapse (seven trials) or breastfeeding continuation (seven trials). Other studies examined support interventions aimed at women at high risk of postnatal depression (two trials) or preterm birth (two trials); the rest of the interventions were designed to offer women more general support and advice. For most of our pre-specified outcomes few studies contributed data, and many of the results described in the review are based on findings from only one or two studies. Overall, results were inconsistent and inconclusive although there was some evidence that telephone support may be a promising intervention. Results suggest that telephone support may increase women's overall satisfaction with their care during pregnancy and the postnatal period, although results for both periods were derived from only two studies. There was no consistent evidence confirming that telephone support reduces maternal anxiety during pregnancy or after the birth of the baby, although results on anxiety outcomes were not easy to interpret as data were collected at different time points using a variety of measurement tools. There was evidence from two trials that women at high risk of depression who received support had lower mean depression scores in the postnatal period, although there was no clear evidence that women who received support were less likely to have a diagnosis of depression. Results from trials offering breastfeeding telephone support were also inconsistent, although the evidence suggests that telephone support may increase the duration of breastfeeding. There was no strong evidence that women receiving telephone support were less likely to be smoking at the end of pregnancy or during the postnatal period. For infant outcomes, such as preterm birth and infant birthweight, overall, there was little evidence. Where evidence was available, there were no clear differences between groups. Results from two trials suggest that babies whose mothers received support may have been less likely to have been admitted to a neonatal intensive care unit (NICU), although it is not easy to understand the mechanisms underpinning this finding. Despite some encouraging findings, there is insufficient evidence to recommend routine telephone support for women accessing maternity services, as the evidence from included trials is neither strong nor consistent. Although benefits were found in terms of reduced depression scores, breastfeeding duration and increased overall satisfaction, the current trials do not provide strong enough evidence to warrant investment in resources.

Plain-language summary: In this review we have included results from 27 randomised trials with more than 12,000 women. All of the trials examined telephone support versus usual care (no additional telephone support). In two trials women received automated text messages. We did not identify any trials comparing different types of telephone support (for example, text messaging versus one-to-one calls). All but one of the trials were carried out in high-resource settings. The majority of studies examined support provided via telephone conversations between women and health professionals although a small number of trials included telephone support from peers. Many of the results described in the review are based on findings from only one or two studies. Overall, results were inconsistent and inconclusive. Telephone support may increase women's overall satisfaction with their care during pregnancy and the postnatal period; although results for both periods were from only two studies. There was no consistent evidence confirming that telephone support reduces anxiety during pregnancy or after the birth of the baby. Evidence from two trials showed that women who received support had lower average depression scores in the postnatal period but without clear evidence that women who were supported were less likely to have a diagnosis of depression. Results from trials encouraging breastfeeding through telephone support were also inconsistent, although there was some evidence that telephone support may increase the duration of breastfeeding. There was no strong evidence that women receiving telephone support were less likely to be smoking at the end of pregnancy or during the postnatal period. For infant outcomes, such as preterm birth and infant birthweight, overall, there was little evidence. Where evidence was available, there were no clear differences between groups. There remains uncertainty regarding the benefit of telephone support and despite some encouraging findings, there is insufficient evidence to recommend routine telephone support for women accessing maternity services.