The recent RCOG guidelines (1) recommend non-closure of peritoneum in many obstetric and gynecological operations. However, standard texts advocate closure of parietal peritoneum in vertical and transverse incisions using delayed absorbable sutures (2). Cesarean section and hysterectomy are the two most commonly performed operations in the United States of America (3). Closure of pelvic peritoneum in abdominal and vaginal hysterectomy is recommended (4). In cesarean sections, closure of at least parietal peritoneum is recommended, whereas non-closure of the bladder flap is deemed appropriate (5). In recent years, animal studies and human observational studies have improved our understanding of the physiology of peritoneal healing (6). Traditional arguments for peritoneal closure have included restoration of anatomy and co-aptation of edges, reduced risk of infection and reduction in adhesion formation and wound dehiscence (1). Studies have shown that many of these arguments are theoretical. Peritoneum heals by proliferation of underlying mesothelial cells, and edge approximation plays little role. Arguments for non-closure include reduced operating time (6). Non-closure has not been shown to be detrimental and suture presence and additional tissue handling may contribute to adhesion formation (1). The work of Ellis (7) has shown that adhesions appear to be vascular grafts, and developed in relation to ischemia induced. He also showed that mere suture presence does not lead to adhesion formation, whereas creation of ischemia does, even in the absence of suture material. It appears that the culprit is ischemia, and not the presence of suture material. 1. Cesarean section – A Cochrane review (8) on peritoneal non-closure at Cesarean section showed that there was a statistically significant reduction in operating time. This reduction of 6.12 minutes may well be statistically significant, but is this clinically significant as well? This difference should be viewed in the light of potential disadvantages. It was found in studies that there was no difference in infectious morbidity in closure and non-closure groups (8–10). One should remember that absence of evidence does not equal evidence of absence and keep in mind the potential impact of publication bias. Randomized controlled trials (RCTs) are not very effective for identification of rarer but potentially dangerous complications like postoperative hemorrhage or intestinal obstruction. Cesarean sections have become very safe. Neither maternal mortality attributable to the operative technique nor parietal hematoma requiring evacuation, were reported in over 1000 Cesarean sections in the Term breech trial (11). Maternal systemic infection was reported in 1.5% cases (11). A trial capable of showing a rise of infectious morbidity with non-closure from 1.5% to 3% would require a sample size of about 1600 in each arm at 0.05% significance and 90% power (12). This topic is currently a subject of a multicenter trial, and recruitment has begun. It is estimated that 3500 women will require to be recruited, and the results will be available after 24 months (13). 2. Hysterectomy – Lipscomb et al. (14) reported an RCT of peritoneal closure v/s non-closure in vaginal hysterectomies. The number of cases was small (106 cases). Curiously, one case of fallopian tube prolapse occurred in the peritoneal closure group. Prolapse of an intestinal loop from the open peritoneum over the vaginal vault with subsequent obstruction remains a concern. Peritoneal non-closure in circumstances that involve intraperitoneal fluid (Dextran, ascites, chemotherapy) has not been sufficiently addressed by current studies. 3. Other evidence – Though Tulandi et al. (15) reported postoperative adhesions forming more frequently (statistically not significant) in the peritoneal closure group, the case allocation was not exactly random. This study, as well as animal experimental studies (16), show that peritoneal adhesions do develop even when peritoneal closure is omitted. The former study reported one case of intestinal obstruction in the closure group. However, evidence from the laparoscopic surgical literature (17) suggests that intestinal herniation through peritoneal defects, with subsequent obstruction, does occur, and that peritoneal defects should be closed. Life-threatening post-operative hemoperitoneum in a case where the peritoneum was left unsutured, has been reported (18). Non-closure of the parietal peritoneum was considered responsible for the late detection of this complication. This shows that the concerns are real, and not theoretical. We need strong evidence to suggest that closure of peritoneum is more detrimental than non-closure before we change our practices. However, given the rarity of some potentially life-threatening complications such as postoperative hemorrhage, serious infection and gastrointestinal complications, RCTs evaluating these may never be conducted. Presently, we must understand the physiology of peritoneal healing, and avoid production of ischemia while closing peritoneum. The author would like to thank Dr. Basky Thilaganathan, Consultant/Senior lecturer, St. George's Hospital Medical School, London, for reviewing the manuscript.