-
1.
Value of intrauterine platelet-rich concentrates in patients with intrauterine adhesions after hysteroscopy: A systematic review and meta-analysis of randomized controlled trials
Korany S, Baradwan S, Badghish E, Talat Miski N, Alshahrani MS, Khadawardi K, Baradwan A, Alanwar A, Labib K, Dahi AA, et al
European journal of obstetrics, gynecology, and reproductive biology. 2022;271:63-70
Abstract
OBJECTIVE To evaluate the value of intrauterine platelet-rich concentrates among patients with intrauterine adhesions (IUAs) after hysteroscopic adhesiolysis. METHODS Four different databases (PubMed, Cochrane Library, Scopus, and ISI web of science) were searched for the available studies from inception to November 2021. We selected randomized clinical trials (RCTs) that compared platelet-rich concentrates in the intervention group versus no injection of platelet-rich concentrates in the control group among women with intrauterine adhesions after operative hysteroscopy. Revman software was utilized for performing our meta-analysis. Our primary outcomes were the adhesion score and incidence of recurrence of severe intrauterine adhesions postoperatively. Our secondary outcomes were the clinical pregnancy rate, menstrual flow duration in days, and menstrual flow amount (number of pads). RESULTS Five RCTs met our inclusion criteria with a total number of 329 patients. We found that platelet-rich concentrates were linked to a significant reduction in the postoperative adhesion score (MD = -1.00, 95% CI [-1.68, -0.32], p = 0.004). Moreover, there was a significant reduction in the incidence of severe IUAs recurrence among the platelet-rich concentrates group (7.6%) compared to the control group (23.4%) after hysteroscopy (p = 0.001). The clinical pregnancy rate was significantly increased among the platelet-rich concentrates group (37.1%) in comparison with the control group (20.7%) after hysteroscopic adhesiolysis (p = 0.008). There were significant improvements in the menstrual flow duration and amount among the platelet-rich concentrates group (p < 0.001). CONCLUSIONS Intrauterine placement of platelet-rich concentrates is an effective method for the treatment of intrauterine adhesions after hysteroscopy.
-
2.
Intraoperative Cell Salvage for Women at High Risk of Postpartum Hemorrhage During Cesarean Section: a Systematic Review and Meta-analysis
Obore N, Liuxiao Z, Haomin Y, Yuchen T, Wang L, Hong Y
Reproductive sciences (Thousand Oaks, Calif.). 2022
Abstract
Postpartum hemorrhage (PPH) can lead to substantial blood loss that compromises maternal hemodynamic stability and consequently cause severe maternal complications such as organ dysfunction or death. Intraoperative cell salvage (IOCS), an effective method of blood conservation used in other surgical specialties, can be an alternative intervention for managing PPH. Thus, our aim was to evaluate the efficacy and safety of IOCS for women at high risk of PPH undergoing cesarean sections. We conducted a systematic search of electronic databases from inception to February 25, 2021 for randomized controlled studies and observational studies published in English or Mandarin about IOCS use in cesarean sections. Primary outcomes of interest were changes in postoperative hematologic parameters and any adverse events reported among patients that had IOCS and controls that had an allogeneic blood transfusion. The certainty of the evidence of the outcomes was evaluated using the GRADE approach. A total of 24 studies with 5872 patients were included in the meta-analysis. Eleven randomized controlled trials (RCTs), and 13 observational studies were analyzed. Postoperative hemoglobin levels were higher among patients with IOCS SMD 0.39 (95% CI; 0.20, 0.60; P < 0.001, high certainty). Allogeneic blood transfusion increased adverse events RR = 1.81(95% CI; 1.24, 2.62; P = 0.002, low certainty). IOCS shortened hospital stay SMD - 0.59 (95% CI: - 0.98, - 0.19; P = 0.004, low certainty) and shortened prothrombin time SMD - 0.67 (95% CI; - 1.31, - 0.04), P = 0.037, low certainty). The lower incidence of transfusion-related adverse events and shorter hospital stay among other findings demonstrate that IOCS use in obstetrics is an effective and safe alternative for the management of PPH; however, high-quality randomized control studies are required to confirm this evidence.
-
3.
Endometrial resection and ablation versus hysterectomy for heavy menstrual bleeding
Bofill Rodriguez M, Lethaby A, Fergusson RJ
The Cochrane database of systematic reviews. 2021;2:Cd000329
Abstract
BACKGROUND Heavy menstrual bleeding (HMB) is common in otherwise healthy women of reproductive age, and can affect physical health and quality of life. Surgery is usually a second-line treatment of HMB. Endometrial resection/ablation (EA/ER) to remove or ablate the endometrium is less invasive than hysterectomy. Hysterectomy is the definitive treatment and can be via open (laparotomy) approach, or via minimally invasive approaches (vaginally or laparoscopically). Each approach has its own advantages and risk profile. OBJECTIVES To compare the effectiveness, acceptability and safety of endometrial resection or ablation versus different routes of hysterectomy (open, minimally invasive hysterectomy, or unspecified route) for the treatment of HMB. SEARCH METHODS We searched the Cochrane Gynaecology and Fertility specialised register, CENTRAL, MEDLINE, Embase and PsycINFO (July 2020), and reference lists, grey literature and trial registers. SELECTION CRITERIA Randomised controlled trials (RCTs) that compared techniques of endometrial resection/ablation with hysterectomy (by any technique) for the treatment of HMB in premenopausal women. DATA COLLECTION AND ANALYSIS We used standard methodological procedures expected by Cochrane. MAIN RESULTS We included 10 RCTs (1966 participants) comparing EA/ER to hysterectomy (open (abdominal), minimally invasive (laparoscopic or vaginal), or unspecified (or at surgeon's discretion) route of hysterectomy). The results were rated as moderate-, low- and very low-certainty evidence. Endometrial resection/ablation versus open hysterectomy We found two trials. Women having EA/ER are probably less likely to perceive an improvement in HMB compared to women having open hysterectomy (risk ratio (RR) 0.90, 95% confidence interval (CI) 0.84 to 0.95; 2 studies, 247 women; moderate-certainty evidence) and probably have a 13% risk of requiring further surgery for treatment failure (compared to 0 on the open hysterectomy group; 2 studies, 247 women; moderate-certainty evidence). Both treatments probably lead to similar quality of life at two years (mean difference (MD) -5.30, 95% CI -11.90 to 1.30; 1 study, 155 women; moderate-certainty evidence) and satisfaction rate at one year (RR 0.91, 95% CI 0.82 to 1.00; 1 study, 194 women; moderate-certainty evidence). There may be no difference in serious adverse events (RR 1.29, 95% CI 0.32 to 5.20; 2 studies, 247 women; low-certainty evidence). EA/ER probably reduces time to return to normal activity compared to open hysterectomy (MD -21.00 days, 95% CI -24.78 to -17.22; 1 study, 197 women; moderate-certainty evidence). Endometrial resection/ablation versus minimally invasive hysterectomy We found five trials. The proportion of women with perception of improvement in HMB at two years may be similar between groups (RR 0.97, 95% CI 0.90 to 1.04; 1 study, 79 women; low-certainty evidence). Blood loss may be higher in the EA/ER group when assessed using the Pictorial Blood Assessment Chart (MD 44.00, 95% CI 36.09 to 51.91; 1 study, 68 women; low-certainty evidence). Quality of life is probably lower in the EA/ER group compared to the minimally invasive hysterectomy group at two years according to the 36-item Short Form (SF-36) (MD -10.71, 95% CI -15.11 to -6.30; 2 studies, 145 women; moderate-certainty evidence) and Menorrhagia Multi-Attribute Scale (RR 0.82, 95% CI 0.70 to 0.95; 1 study, 616 women; moderate-certainty evidence). EA/ER probably increases the risk of further surgery for HMB compared to minimally invasive hysterectomy (RR 7.70, 95% CI 2.54 to 23.32; 4 studies, 922 women; moderate-certainty evidence) and treatments probably have similar rates of any serious adverse events (RR 0.75, 95% CI 0.35 to 1.59; 4 studies, 809 women; moderate-certainty evidence). Women with EA/ER are probably less likely to be satisfied with treatment at one year (RR 0.90, 95% CI 0.85 to 0.94; 1 study, 558 women; moderate-certainty evidence). We were unable to pool data for time to return to work or normal life because of extreme heterogeneity (99%); however, the three studies reporting this all had the same direction of effect favouring EA/ER. Endometrial resection/ablation versus unspecified route of hysterectomy We found three trials. EA/ER may lead to a lower perception of improvement in HMB compared to unspecified route of hysterectomy (RR 0.89, 95% CI 0.83 to 0.95; 2 studies, 403 women; low-certainty evidence). Although EA/ER may lead to similar quality of life using the SF-36 General Health Perception at two years' follow-up (MD -1.90, 95% CI -8.67 to 4.87; 1 study, 209 women; low-certainty evidence), the proportion of women with improvement in general health at one year may be lower (RR 0.85, 95% CI 0.77 to 0.95; 1 study, 185 women; low-certainty evidence). EA/ER probably has a risk of 5.4% of requiring further surgery for treatment failure (compared to 0 with total hysterectomy; 2 studies, 374 women; moderate-certainty evidence) and reduces the proportion of women with any serious adverse event (RR 0.21, 95% CI 0.06 to 0.80; 2 studies, 374 women; moderate-certainty evidence). Both treatments probably lead to a similar satisfaction rate at one year' follow-up (RR 0.96, 95% CI 0.88 to 1.04; 3 studies, 545 women; moderate-certainty evidence). EA/ER may lead to shorter time to return to normal activity (MD -18.90 days, 95% CI -24.63 to -13.17; 1 study, 172 women; low-certainty evidence). AUTHORS' CONCLUSIONS Endometrial resection/ablation (EA/ER) offers an alternative to hysterectomy as a surgical treatment for HMB. Effectiveness varies with EA/ER compared to different hysterectomy approaches. The perception of improvement in HMB with EA/ER is probably lower compared to open and unspecified route of hysterectomy, but may be similar compared to minimally invasive. Quality of life with EA/ER is probably similar to open and unspecified route of hysterectomy, but lower compared to minimally invasive hysterectomy. Further surgery for treatment failure is probably more likely with EA/ER compared to all routes of hysterectomy. Satisfaction rates also vary. EA/ER probably has a similar rate of satisfaction compared to open and unspecified route of hysterectomy, but a lower rate of satisfaction compared to minimally invasive hysterectomy. The proportion having any serious adverse event appears similar in all groups, but specific adverse events did reported difference between EA/ER and different routes. We were unable to draw conclusions about the time to return to normal activity, but the direction of effect suggests it is likely to be shorter with EA/ER.
-
4.
Impact of anesthetic agents on the amount of bleeding during dilatation and evacuation: A systematic review and meta-analysis
Lee HA, Kawakami H, Mihara T, Sato H, Goto T
PloS one. 2021;16(12):e0261494
Abstract
PURPOSE Patients undergo dilatation and evacuation for abortion or miscarriage. However, bleeding is sometimes problematic. Despite reports on the association between volatile anesthetics and increased bleeding during the procedure, firm evidence is lacking. Therefore, we conducted a systematic review and meta-analysis to compare the effects of volatile anesthetics and propofol on the amount of bleeding in patients undergoing dilatation and evacuation. METHODS We conducted a systematic search of four databases, namely PubMed, Embase, Cochrane Central Register of Controlled Trials databases, and Web of Science (Clarivate Analytics), from their respective inception to April 2021. Moreover, we searched two trial registration sites. The inclusion criterion was randomized controlled trials of patients who underwent dilatation and evacuation under general anesthesia using volatile anesthetics or propofol. The primary outcome was the amount of perioperative bleeding. The mean difference of the bleeding was combined using a random-effects model. The I2 statistic was used to assess heterogeneity. We assessed risk of bias with Cochrane domains. We controlled type I and II errors due to sparse data and repetitive testing with Trial Sequential Analysis. We assessed the quality of evidence with GRADE. RESULTS Five studies were included in the systematic review. The amount of bleeding was compared in four studies and was higher in the volatile anesthetic group, with a mean difference of 164.7 ml (95% confidence interval, 43.6 to 285.7; p = 0.04). Heterogeneity was considerable, with an I2 value of 97%. Two studies evaluated the incidence of significant bleeding, which was significantly higher in the volatile anesthetic group (RR, 2.42; 95% confidence interval, 1.04-5.63; p = 0.04). CONCLUSION Choosing propofol over volatile anesthetics during dilatation and evacuation might reduce bleeding and the incidence of excessive bleeding. However, the quality of the evidence was very low. This necessitates further trials with a low risk of bias. TRIAL REGISTRATION PROSPERO (CRD42019120873).
-
5.
Effects of colloid preload on the incidence of hypotension in spinal anesthesia for cesarean section: a systematic review and meta-analysis
Gong RS, Liu XW, Li WX, Zhao J
Chinese medical journal. 2021
-
-
Free full text
-
Abstract
BACKGROUND Hypotension is a common complication caused by spinal anesthesia (SA), which may have adverse impacts on the condition of the parturient and fetus. Liquid infusion was found to be relatively effective for reducing the incidence of hypotension. However, the question of whether colloid preload can optimize hemodynamic variables in the cesarean section remains controversial. This study aims to determine the effects of colloid preload on the incidence of hypotension induced by SA in elective cesarean section. METHODS Related keywords were searched on PubMed, EMBASE, and Cochrane Library from inception dates to May 2020. Studies included were evaluated for eligibility and quality. The primary outcome was the intra-operative incidence of hypotension and severe hypotension. The secondary outcomes included the lowest intra-operative systolic blood pressure, the maximal intra-operative heart rate, the intra-operative needs of ephedrine and phenylephrine, the incidence of maternal nausea and/or vomiting, and neonatal outcomes (umbilical artery pH and Apgar scores). Apart from the above, RevMan 5.3 was used for the data analysis. RESULTS Altogether nine randomized controlled trials were included in the meta-analysis. There were no significant differences in the incidence of intra-operative hypotension, severe hypotension, or neonatal outcomes between the colloid preload group and control group, except for the umbilical artery pH. CONCLUSION This meta-analysis suggests that colloid preload does not significantly reduce the incidence of hypotension associated with SA in elective cesarean section.
-
6.
Tranexamic acid for the prevention of postpartum hemorrhage in women undergoing cesarean delivery: an updated meta-analysis
Bellos I, Pergialiotis V
American journal of obstetrics and gynecology. 2021
-
-
-
-
Editor's Choice
Abstract
OBJECTIVE To assess the efficacy and safety of prophylactic tranexamic acid administration in comparison with standard uterotonic agents alone among women undergoing cesarean delivery. DATA SOURCES Medline, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, Clinicaltrials.gov and Google Scholar were systematically searched from inception to June 30, 2021. STUDY ELIGIBILITY CRITERIA Randomized controlled trials comparing intravenous tranexamic acid administration to placebo in women undergoing cesarean delivery and receiving standard prophylactic uterotonic agents were held eligible. STUDY APPRAISAL AND SYNTHESIS METHODS The risk of bias of individual studies was appraised with the RoB-2 tool. Meta-analysis was conducted by fitting random-effects models using restricted maximum likelihood. Subgroup analysis was performed based on country, protocol availability, double-blinding, risk of bias, sample size and tranexamic acid dose. One-stage meta-analysis was performed as a sensitivity analysis. The credibility of outcomes was appraised with the Grading of Recommendations Assessment, Development and Evaluation approach. RESULTS Overall, 36 studies with 10,659 women were included. Tranexamic acid administration was associated with significantly lower total blood loss (Mean difference-MD: -189.44 ml, 95% confidence intervals-CI: -218.63; -160.25), lower hemoglobin drop (MD: 8.22%, 95% CI: 5.54; 10.90), decreased risk of blood loss >1000 ml (Odds ratio-OR: 0.37, 95% CI: 0.22; 0.60), transfusion requirement (OR: 0.41, 95% CI: 0.26; 0.65) and need of additional uterotonics (OR: 0.36, 95% CI: 0.25; 0.52). Subgroup analysis indicated a greater effect of tranexamic acid on total blood loss reduction in low-middle income countries. The outcomes remained stable by separately evaluating women at low bleeding risk. One-stage meta-analysis demonstrated similar outcomes with the primary analysis. The quality of evidence was judged to be moderate regarding total blood loss and hemoglobin percentage change and low for the other outcomes. CONCLUSIONS This meta-analysis suggests that prophylactic tranexamic acid administration is effective among women undergoing cesarean delivery in lowering postpartum blood loss and limiting hemoglobin drop. Further research is needed to test its efficacy in high-risk populations and to verify its safety profile.
PICO Summary
Population
Women undergoing caesarean delivery (36 studies, n= 10,659).
Intervention
Tranexamic acid.
Comparison
Standard uterotonic agents alone.
Outcome
Tranexamic acid administration was associated with significantly lower total blood loss (Mean difference (MD): -189.44 ml), lower haemoglobin drop (MD: 8.22%), decreased risk of blood loss >1000 ml, transfusion requirement and need of additional uterotonics. Subgroup analysis indicated a greater effect of tranexamic acid on total blood loss reduction in low-middle income countries. The outcomes remained stable by separately evaluating women at low bleeding risk. One-stage meta-analysis demonstrated similar outcomes with the primary analysis. The quality of evidence was judged to be moderate regarding total blood loss and haemoglobin percentage change and low for the other outcomes.
-
7.
Tranexamic acid for prevention of bleeding in caesarean Delivery: an overview of systematic reviews
Hurskainen T, Deng MX, Etherington C, Burns J, Martin Calderon L, Moher D, Edwards W, Boet S
Acta anaesthesiologica Scandinavica. 2021
-
-
-
-
Editor's Choice
Abstract
BACKGROUND Bleeding is the leading cause of maternal mortality in the world. Tranexamic acid reduces bleeding in trauma and surgery. Several systematic reviews of randomized trials have investigated tranexamic acid in the prevention of bleeding in caesarean delivery. However, the conclusions from systematic reviews are conflicting. This overview aims to summarize the evidence and explore the reasons for conflicting conclusions across the systematic reviews. METHODS A comprehensive literature search of Medline, Embase, and Cochrane Database of Systematic Reviews was conducted from inception to April 2021. Screening, data extraction, and quality assessments were performed by two independent reviewers. A Measurement Tool to Assess Reviews 2 and the Risk of Bias Assessment Tool for Systematic Reviews were used for study appraisal. A qualitative synthesis of evidence is presented. RESULTS Fourteen systematic reviews were included in our analysis. Across these reviews, there were 32 relevant randomized trials. A modest reduction in blood transfusions and bleeding outcomes was found by most systematic reviews. Overall confidence in results varied from low to critically low. All of the included systematic reviews were at high risk of bias. Quality of evidence from randomized trials was uncertain. CONCLUSIONS Systematic reviews investigating prophylactic tranexamic acid in caesarean delivery are heterogeneous in terms of methodological and reporting quality. Tranexamic acid may reduce blood transfusion and bleeding outcomes, but rigorous well-designed research is needed due to the limitations of the included studies. Data on safety and adverse effects is insufficient to draw conclusions.
PICO Summary
Population
Patients undergoing caesarean delivery (14 studies).
Intervention
Overview of systematic reviews on tranexamic acid for the prevention of bleeding.
Comparison
Outcome
A modest reduction in blood transfusions and bleeding outcomes was found by most systematic reviews. Overall confidence in results varied from low to critically low. All of the included systematic reviews were at high risk of bias. Quality of evidence from randomized trials was uncertain.
-
8.
The combined use of endometrial ablation or resection and levonorgestrel-releasing intrauterine system in women with heavy menstrual bleeding: A systematic review
Oderkerk TJ, van de Kar MMA, van der Zanden CHM, MAJ Geomini P, Herman MC, Bongers MY
Acta obstetricia et gynecologica Scandinavica. 2021
Abstract
INTRODUCTION Despite the fact that endometrial ablation/resection is a very successful treatment for women with heavy menstrual bleeding, re-intervention with additional surgery is needed in 12-25% of the cases. Introducing a levonorgestrel-intrauterine system (LNG-IUS) immediately after ablation could preserve the integrity of the uterine cavity and suppress the regenerated or non-ablated endometrial tissue. Therefore, this combined treatment can perhaps lower the re-intervention rate. The aim of this systematic review was to assess the impact of the combined treatment. MATERIAL AND METHODS The MEDLINE, EMBASE and Cochrane library were systematically searched. No language restrictions were applied. All types of studies were included reporting on the results of endometrial ablation or resection combined with immediate insertion of LNG-IUS for treatment of heavy menstrual bleeding. The primary outcome was the number of hysterectomies after the ablation procedure. Secondary outcomes included re-intervention rates, removals of LNG-IUS, bleeding pattern, patient satisfaction, side-effects and complications. Our protocol was registered in PROSPERO, an international prospective register of systematic reviews under registration number CRD42020151384. RESULTS Six studies with a retrospective design and one case series with a follow up duration varying from 6 to 55 months were included. In total, 427 women were treated with the combined treatment. The studies described a lower hysterectomy and re-intervention rate after combined treatment compared to treatment with endometrial ablation/resection alone. Hysterectomy rate varied from 0-11% after combined treatment versus 9.4-24% after endometrial ablation/resection alone. Bleeding patterns and patient satisfaction appeared to be in favour of the combined treatment group. No intra or post operation complications or complications in the removal of LNG-IUS were described. Most described side effects after combined treatment were weight gain, mood changes and head-aches. An additional eleven studies with only an abstract available substantiated these findings. All the included studies had poor methodologic quality. CONCLUSIONS Based on the available literature inserting an LNG-IUS immediately after endometrial ablation/resection seems to lower the hysterectomy and re-intervention rates compared to ablation/resection alone. However, since only limited observational studies of low methodological quality are available, high quality research is necessary to confirm the findings of this systematic review.
-
9.
Timing of oxytocin administration to prevent post-partum hemorrhage in women delivered by cesarean section: A systematic review and metanalysis
Torloni MR, Siaulys M, Riera R, Cabrera Martimbianco AL, Leite Pacheco R, Latorraca COC, Widmer M, Betrán AP
PloS one. 2021;16(6):e0252491
Abstract
BACKGROUND There is no consensus on the best timing for prophylactic oxytocin administration during cesarean section (CS) to prevent post-partum hemorrhage (PPH). OBJECTIVES Assess the effects of administrating prophylactic oxytocin at different times during CS. METHODS We searched nine databases to identify relevant randomized controlled trials (RCT). We pooled results and calculated average risk ratios (RR), mean differences (MD), and 95% confidence intervals (CI). We used GRADE to assess the overall evidence certainty. RESULTS We screened 13,389 references and included four trials. We found no statistically significant differences between oxytocin given before versus after fetal delivery on PPH (RR 0.60, 95%CI 0.15-2.47; 1 RCT, N = 300) or nausea/vomiting (RR 1.21, 95%CI 0.69-2.13; 1 RCT, N = 300). There was a significant reduction in the need for additional uterotonics when oxytocin was given immediately before uterine incision versus after fetal delivery (RR 0.37, 95%CI 0.18-0.73; I2 = 0%; 2 RCTs; N = 301). Oxytocin given before fetal delivery significantly reduced intra-operative blood loss (MD -146.77mL, 95%CI -168.10 to -125.43; I2 = 0%; 3 RCTs, N = 601) but did not change the incidence of blood transfusion (RR 0.50, 95%CI 0.13-1.95; I2 = 0%; 2 RCTs, N = 301) or hysterectomy (RR 3.00; 95%CI 0.12-72.77; I2 = 0%; 2 RCTs, N = 301). One trial (N = 100) compared prophylactic oxytocin before versus after placental separation and found no significant differences on PPH, additional uterotonics, or nausea/vomiting. CONCLUSIONS In women having pre-labor CS, there is limited evidence indicating no significant differences between prophylactic oxytocin given before versus after fetal delivery on PPH, nausea/vomiting, blood transfusion, or hysterectomy. Earlier oxytocin administration may reduce the volume of blood loss and need for additional uterotonics. There is very limited evidence suggesting no significant differences between prophylactic oxytocin given before versus after placental separation on PPH, need for additional uterotonic, or nausea/vomiting. The overall certainty of the evidence was mostly low or very low due to imprecision. Protocol: CRD42020186797.
-
10.
Intravenous oxytocin dosing regimens for postpartum hemorrhage prevention at cesarean section: a systematic review and meta-analysis
Phung LC, Farrington EK, Connolly M, Wilson AN, Carvalho B, Homer CSE, Vogel JP
American journal of obstetrics and gynecology. 2021
Abstract
OBJECTIVE To synthesize available evidence on intravenous (IV) oxytocin dosing regimens for the prevention of postpartum hemorrhage (PPH) at cesarean section (CS). DATA SOURCES We searched Medline/OVID, Embase, Global Index Medicus, CINAHL, CENTRAL, ClinicalTrials.gov, and ICTRP for eligible studies published until Feb 2020. STUDY ELIGIBILITY CRITERIA We included any randomized or non-randomized study published in peer-reviewed journals that compared at least two different dosing regimens of IV oxytocin for PPH prevention in women undergoing CS. STUDY APPRAISAL AND SYNTHESIS METHODS Two authors independently assessed eligibility, extracted data, and assessed risk of bias. Primary outcome was incidence of PPH ≥ 1000 mL. Other review outcomes included use of additional uterotonics, blood loss, and adverse maternal events. Data were analyzed based on type of IV administration (bolus only, infusion only, bolus plus infusion) and oxytocin dose. Meta-analysis was performed using randomized trials and reported using risk ratios or mean difference with 95% confidence intervals. GRADE was used to rate the certainty of evidence. Findings from dose-finding trials and non-randomized studies were reported narratively. RESULTS Thirty-five studies (7,333 women) met our inclusion criteria, including 30 randomized trials and five non-randomized studies. There were limited data from trials for most outcomes, and results were not conclusive. Compared to bolus plus infusion regimens, bolus only regimens probably result in slightly higher mean blood loss (MD 52 mL, 95% CI 0.4-104 mL, moderate certainty). Amongst bolus plus infusion regimens, initial bolus doses < 5 IU may reduce nausea (RR 0.26, 95% CI 0.11-0.63, low certainty) as compared to 5-9 IU. Total oxytocin doses 5-9 IU versus 10-19 IU may increase use of additional uterotonics (RR 13.00, 95% CI 1.75-96.37, low certainty). Effects on other outcomes were generally inconclusive. CONCLUSION There are limited data comparing IV oxytocin regimens for PPH prevention at CS. Bolus plus infusion regimens may lead to minor reductions in mean blood loss, and initial bolus doses of < 5 IU may minimize nausea. Bolus only regimens of 10 IU versus 5 IU may decrease use of additional uterotonics, however further comparative trials are required to understand effects on other key outcomes, particularly hypotension.