Every day in the United Kingdom alone, approximately 1000 women will experience perineal repair following vaginal birth. The impact of perineal trauma can be extremely distressing for a new mother during the early postnatal period when she is trying to cope with hormonal changes, the demands of her baby and pressures imposed by her changing role. For women who sustain perineal injury, it's important that skilled operators repair the trauma, and that they use the best suturing techniques and materials, in order to minimise any associated short- and long-term morbidity. Our Cochrane review was one of the first systematic reviews to be included in The Cochrane Library and was carried out initially by the late Professor Richard Johanson and myself in 1997 (1). It had begun its life even earlier in the 1990s, as a pre-Cochrane review compiled by Professor Adrian Grant. However, it has remained an important topic into the 2000s and was one of 50 maternity care reviews identified as a priority for updating with a project grant from the National Institute for Health Research in England. This provided support from Therese Dowswell in the Cochrane Pregnancy and Childbirth Group editorial base, which proved to be invaluable in assisting Khaled Ismail and me to expand and update the review in a relatively short period of time. Our review now examines a broader range of absorbable sutures, including fast-absorbing synthetic materials, and provides results for new comparisons (2). The included studies were carried out over a period of almost 40 years, in contexts where local customs and practices differed considerably. During this time, catgut has been largely superseded by absorbable synthetic suture materials for perineal repair in high-income countries, but it is still used in some countries, such as Brazil, that are resource poor. The eight studies in the previous version of the review have been supplemented by 10 new studies with over 10,000 women participating in the research. Among the comparisons are nine trials of catgut versus standard synthetic sutures, two trials against rapidly absorbing synthetic standard sutures; and five trials of synthetic sutures versus rapidly absorbing synthetic sutures. Our comprehensive, up-to-date review provides conclusive evidence that perineal repair with catgut may increase short-term pain and wound breakdown compared to synthetic sutures. We found few differences between standard polyglactin 910 and rapidly absorbed synthetic sutures, however fewer women allocated the rapidly absorbed suture material needed sutures removing up to three months postpartum, compared to those who had standard material. This is important because women needing perineal sutures to be removed find it to be an extremely unpleasant procedure. In addition, if sutures remain in the tissues for a longer period than is required, they may cause a significant inflammatory response and increase the risk of infection. When interpreting the results of this collection of trials, it is important to consider the clinical heterogeneity across the included studies. They differed considerably in suturing techniques, the calibre of material, size of needle, skill of operators, duration of follow up and outcomes assessed. Therefore, our findings also need to be interpreted in the context of the related review on suturing techniques (3), but they provide an important new landmark for the evidence base on sutures.