Efficacy of carbetocin in the prevention of postpartum hemorrhage: a systematic review and Bayesian meta-analysis of randomized trials

Third stage of labor: evidence-based practice for prevention of adverse maternal and neonatal outcomes

The third stage of labor is defined as the time period between delivery of the fetus through delivery of the placenta. During a normal third stage, uterine contractions lead to separation and expulsion of the placenta from the uterus. Postpartum hemorrhage is a relatively common complication of the third stage of labor. Strategies have been studied to mitigate the risk of postpartum hemorrhage, leading to the widespread implementation of active management of the third stage of labor. Initially, active management of the third stage of labor consisted of a bundle of interventions including administration of a uterotonic agent, early cord clamping, controlled cord traction, and external uterine massage. However, the effectiveness of these interventions as a bundle has been questioned, leading to abandonment of some components in recent years. Despite this, upon review of selected international guidelines, we found that the term "active management of the third stage of labor" was still used, but recommendations for and against individual interventions were variable and not necessarily supported by current evidence. In this review, we: (1) examine the physiology of the third stage of labor, (2) present evidence related to interventions that prevent postpartum hemorrhage and promote maternal and neonatal health, (3) review current global guidelines and recommendations for practice, and (4) propose future areas of investigation. The interventions in this review include pharmacologic agents to prevent postpartum hemorrhage, cord clamping, cord milking, cord traction, cord drainage, early skin-to-skin contact, and nipple stimulation. Treatment of complications of the third stage of labor is outside of the scope of this review. We conclude that current evidence supports the use of effective pharmacologic postpartum hemorrhage prophylaxis, delayed cord clamping, early skin-to-skin contact, and controlled cord traction at delivery when feasible. The most effective uterotonic regimens for preventing postpartum hemorrhage after vaginal delivery include oxytocin plus ergometrine; oxytocin plus misoprostol; or carbetocin. After cesarean delivery, carbetocin or oxytocin as a bolus are the most effective regimens. There is inconsistent evidence regarding the use of tranexamic acid in addition to a uterotonic compared with a uterotonic alone for postpartum hemorrhage prevention after all deliveries. Because of differences in patient comorbidities, costs, and availability of resources and staff, decisions to use specific prevention strategies are dependent on patient- and system-level factors. We recommend that the term "active management of the third stage of labor" as a combined intervention no longer be used. Instead, we recommend that "third stage care" be adopted, which promotes the implementation of evidence-based interventions that incorporate practices that are safe and beneficial for both the woman and neonate.

Preventing postpartum hemorrhage with combined therapy rather than oxytocin alone

Postpartum hemorrhage is the leading cause of maternal morbidity and mortality worldwide, with uterine atony estimated to account for 70% to 80% of cases, thereby remaining the single most common cause. Pharmacotherapy remains the first-line preventative therapy for postpartum hemorrhage. These therapies may be single (oxytocin, carbetocin, methylergonovine, ergometrine, misoprostol, prostaglandin analogs, or tranexamic acid) or combination therapies, acting in an additive, infra-additive, or synergistic fashion to prevent postpartum hemorrhage. Evidence is strong for the use of oxytocin, the first-line uterotonic agent in the United States for prevention of postpartum hemorrhage. Although carbetocin, a long-acting analog of oxytocin, is not yet available for use in the United States, it is likely the most effective single pharmacologic therapy for prevention of postpartum hemorrhage and need for additional uterotonics. Use of second-line uterotonics such as methylergonovine, misoprostol, and carboprost in combination with oxytocin has an additive or synergistic effect and a greater risk reduction for postpartum hemorrhage prevention compared with oxytocin alone. Therefore, combined therapy rather than oxytocin alone should be advised for preventing postpartum hemorrhage. Tranexamic acid has been found to be both effective and safe for decreasing maternal mortality in women with postpartum hemorrhage, and prophylactic use of tranexamic acid may decrease the need for packed red blood cell transfusions and/or uterotonics. The WOMAN-2 Trial, designed to assess if tranexamic acid prevents postpartum hemorrhage in women with moderate to severe anemia undergoing vaginal delivery, is currently recruiting participants. The additive, infra-additive, or synergistic action of oxytocin in combination with other second-line therapies deserves further study.

Pharmacological Interventions in Labor and Delivery

While there is not a wide range of pregnancy-specific drugs, there are some very specific high-risk areas of obstetric care for which unique pharmacological approaches have been established. In preterm birth, labor induction and augmentation, and the management of postpartum hemorrhage, these pharmacological approaches have become the bedrock in managing some of the most common and problematic areas of antenatal and intrapartum care. In this review, we summarize the existing established and emerging evidence that supports and broadens these pharmacological approaches to obstetric management and its impact on clinical practice. It is clear that existing therapeutics are limited. They have largely been developed from our knowledge of the physiology of the myometrium and act on hormonal receptors and their signaling pathways or on ion channels influencing excitability. Newer drugs in development are mostly refinements of these two approaches, but novel agents from plants and improved formulations are also discussed.

Effect of Baogong Zhixue Granules Combined with Tranexamic Acid Injection on the Hemodynamics and Reproductive System in Patients with Postpartum Hemorrhage after Cesarean Section

Objective

To investigate the effect of Baogong Zhixue granules combined with tranexamic acid injection on the hemodynamics and reproductive system in patients with postpartum hemorrhage (PPH) after cesarean section.

Methods

The data of 90 puerperae undergoing cesarean section in our hospital from January 2019 to January 2020 were retrospectively analyzed. According to the order of admission, they were equally divided into the control group (CG) and experimental group (EG). CG was treated with tranexamic acid injection combined with oxytocin, while EG was treated with Baogong Zhixue granules combined with tranexamic acid injection to compare the clinical observation indexes between the two groups.

Results

Compared with CG, EG achieved remarkably less amount of bleeding at 2 h and 24 h after delivery (P < 0.001), lower postpartum APTT, PT, HR, and MAP (P < 0.001), shorter maintenance time of uterine contraction and lochia (P < 0.001), and lower postpartum FSH and LH (P < 0.001). After delivery, EG had higher postpartum Fib and descending speed of uterine fundus and E₂ compared with CG (P < 0.001).

Conclusion

Baogong Zhixue granules combined with tranexamic acid injection have little effect on the reproductive system of PPH patients after cesarean section, stabilize the hemodynamics, and improve the coagulation function. Therefore, further research on the combined treatment can provide better hemostatic schemes for such patients.

Current Resources for Evidence-Based Practice, November 2021

An extensive review of new resources to support the provision of evidence-based care for women and infants. The current column includes a discussion of autonomy and respect in maternity care and commentaries on reviews focused on whether to induce women who present with mild preeclampsia in the late preterm period and the extent to which urinary incontinence symptoms prevent women from participating in exercise. It also includes a brief update about the USPSTF guidelines on screening for gestational diabetes.

Risk Factors for Carbetocin Failure after a Cesarean Section: Is Obesity One of Them?

Obese pregnant women have increased rates of fetal macrosomia, long labor, and cesarean sections, which lead to an increased risk of postpartum hemorrhage (PPH). Carbetocin is useful for the prevention of PPH after a cesarean section. Our study aimed to investigate predictors of carbetocin failure after a cesarean section, and specifically whether obesity is associated with carbetocin failure. We retrospectively analyzed all women who received carbetocin after a cesarean section. Carbetocin failure was defined as changes in hematocrit and hemoglobin, blood loss ≥ 1000 mL, and the need for an additional uterotonic agent or second-line therapies for persistent PPH. Univariate and multivariate analyses were performed to investigate predictors of carbetocin failure. The study included 600 women, with 131 (21.8%) obese women. Overall, 44 (7.3%) carbetocin failures were reported, and rates of obese women were similar between groups (carbetocin failure, 11.4% vs. 22.9%; p = 0.08). Previous PPH (p < 0.001), a cesarean section during labor (p = 0.01), cervical ripening (p = 0.02), and birthweight (p = 0.01) were significantly different between groups. In the multivariable logistic regression analysis adjusted for potential confounders, cervical ripening (adjusted odds ratio (OR) 2.23, 95% confidence interval (CI) 1.01–4.80), compared with spontaneous labor, was significantly associated with carbetocin failure. Obesity was not associated with carbetocin failure after cesarean sections.

Refractory uterine atony: still a problem after all these years

Postpartum hemorrhage is a leading cause of maternal morbidity and mortality, and uterine atony is the leading cause of postpartum hemorrhage. Risk factors for uterine atony include induced or augmented labor, preeclampsia, chorio-amnionitis, obesity, multiple gestation, polyhydramnios, and prolonged second stage of labor. Although a risk assessment is recommended for all parturients, many women with uterine atony do not have risk factors, making uterine atony difficult to predict. Oxytocin is the first-line drug for prevention and treatment of uterine atony. It is a routine component of the active management of the third stage of labor. An oxytocin bolus dose as low as 1 IU is sufficient to produce satisfactory uterine tone in almost all women undergoing elective cesarean delivery. However, a higher bolus dose (3 IU) or infusion rate is recommended for women undergoing intrapartum cesarean delivery. Carbetocin, available in many countries, is a synthetic oxytocin analog with a longer duration than oxytocin that allows bolus administration without an infusion. Second line uterotonic agents include ergot alkaloids (ergometrine and methylergonovine) and the prostaglandins, carboprost and misoprostol. These drugs work by a different mechanism to oxytocin and should be administered early for uterine atony refractory to oxytocin. Rigorous studies are lacking, but methylergonovine and carboprost are likely superior to misoprostol. Currently, the choice of second-line agent should be based on their adverse effect profile and patient comorbidities. Surgical and radiologic management of uterine atony includes uterine tamponade using balloon catheters and compression sutures, and percutaneous transcatheter arterial embolization.

Preventing term stillbirth: benefits and limitations of using fetal growth reference charts

PURPOSE OF REVIEW

This review examines the variation in clinical practice with regards to ultrasound estimation of fetal weight, as well as calculation of fetal weight centiles.

RECENT FINDINGS

Placental dysfunction is associated with fetal smallness from intrauterine malnutrition as well as fetal disability and even stillbirth from hypoxemia. Although estimating fetal weight can be done accurately, the issue of which fetal weight centile chart should be used continues to be a contentious topic. The arguments against local fetal growth charts based on national borders and customization for variables known to be associated with disease are substantial. As for other human diseases such as hypertension and diabetes, there is a rationale for the use of an international fetal growth reference standard. Irrespective of the choice of fetal growth reference standard, a significant limitation of small for gestational age (SGA) detection programs to prevent stillbirth is that the majority of stillborn infants at term were not SGA at the time of demise.

SUMMARY

Placental dysfunction can present with SGA from malnutrition and/or stillbirth from hypoxemia depending on the gestational age of onset. Emerging data show that at term, fetal Doppler arterial redistribution is associated more strongly with perinatal death than fetal size. Properly conducted trials of the role for maternal characteristics, fetal size, placental biomarkers, and Doppler assessing fetal well-being are required urgently.

Initial management of primary postpartum hemorrhage: a survey

OBJECTIVE

The objective of this study is to evaluate the actions taken by obstetricians when faced with postpartum hemorrhage (PPH).

MATERIALS AND METHODS

A standardized open-ended survey was applied to 235 physicians at five hospitals and at an obstetrics and gynecology conference, inquiring about which actions are recommended in the initial stages of PPH. We calculated the frequency and confidence intervals of the actions mentioned and correlated the number of actions with the number of clinicians mentioning them using Spearman's rho test.

RESULTS

Asking for help was mentioned by 45% of the respondents and 38% asked for vital signs. Only one-fifth of those surveyed asked for blood count, coagulation testing, arterial blood gas, or urinary catheter. Very few mentioned hypothermia prevention, oxygen administration, or blood transfusion. A total of 80% of those interviewed only mentioned 3 of the 16 recommended actions.

CONCLUSION

Postpartum hemorrhage training should include instructions on initial steps in order to improve treatment comprehension and outcomes.