Current State and Future Direction of Postpartum Hemorrhage Risk Assessment

Application of Predictive Analytics in Pregnancy, Birth, and Postpartum Nursing Care

ABSTRACT

Predictive analytics has emerged as a promising approach for improving reproductive health care and patient outcomes. During pregnancy and birth, the ability to accurately predict risks and complications could enable earlier interventions and reduce adverse events. However, there are challenges and ethical considerations for implementing predictive models in perinatal care settings. We introduce major concepts in predictive analytics and describe application of predictive modeling to perinatal care topics such as fertility, preeclampsia, labor onset, vaginal birth after cesarean, uterine rupture, induction outcomes, postpartum hemorrhage, and postpartum mood disorders. Although some predictive models have achieved adequate accuracy (AUC 0.7-0.9), most require additional external validation across diverse populations and practice settings. Bias, particularly racial bias, remains a key limitation of current models. Nurses and advanced practice nurses, including nurse practitioners certified registered nurse anesthetists, and nurse-midwives, play a vital role in ensuring high-quality data collection and communicating predictive model outputs to clinicians and users of the health care system. Addressing the ethical challenges and limitations of predictive analytics is imperative to equitably translate these tools to support patient-centered perinatal care.

Association between psychopharmacotherapy and postpartum hemorrhage

Background

Prior studies evaluating the relationship between psychopharmacotherapy (PPT), and postpartum hemorrhage (PPH) have yielded inconsistent findings. Clarifying this potential relationship is important for effective counseling and risk stratification.

Objectives

Our primary objective was to evaluate the association between prenatal exposure to PPT (any drug class) and the occurrence of PPH requiring transfusion of packed red blood cells (PPH+pRBC) after systematically adjusting for known hemorrhage risk factors at the time of admission for delivery. Secondary objectives were to evaluate the association between individual PPT drug classes and PPH+pRBC, and the association between treatment intensity of mental health condition and PPH+pRBC. Finally, we evaluated the association between PPT and a broader definition of PPH that included deliveries requiring multiple uterotonic drugs.

Study design

This is a retrospective cross-sectional study of all pregnancies delivered at 23 weeks of gestational age or greater at seven hospitals within a large academic health system in New York between January 2019 and December 2022. There were no exclusion criteria, as postpartum hemorrhage risk assessment is necessary for all patients admitted for delivery. We assessed exposure to prenatal PPT, including selective serotonin reuptake inhibitors (SSRIs: escitalopram, fluoxetine, sertraline), serotonin-norepinephrine reuptake inhibitors (SNRIs: duloxetine, venlafaxine), dopamine-norepinephrine reuptake inhibitors (DNRIs: buproprion), benzodiazepines (alprazolam, diazepam, lorazepam), and others (buspirone, trazodone, zolpidem). Multivariable logistic regression was performed to evaluate the relationship between PPT and PPH+pRBC, while systematically adjusting for known hemorrhage risk factors at the time of hospital admission. Similar regression analyses were performed to address the secondary objectives.

Results

A total of 107,425 deliveries were included. Non-Hispanic White patients constituted the largest race and ethnicity group (43.4%), followed by Hispanic patients (18.7%), Asian or Pacific Islander patients (13.2%), and non-Hispanic Black patients (12.3%). Prenatal exposure to PPT occurred in 3.6% of pregnancies (n=3,834). The overall rate of PPH+pRBC was 2.9% (n=3,162). PPH+pRBC occurred more frequently in pregnancies exposed to PPT than in pregnancies which were not exposed (5.5% vs. 2.8%, respectively; aOR 2.10, 95% CI: 1.79-2.44). SSRIs and benzodiazepine monotherapy were each associated with higher odds of PPH+pRBC than nonexposure. Compared to patients without a mental health condition, monotherapy was associated with nearly 2-fold increased odds and combination PPT was associated with nearly 4-fold greater odds of PPH+pRBC after adjustment for confounding variables (monotherapy: aOR 1.94, 95% CI: 1.64-2.28; combination PPT: aOR 3.96, 95% CI: 2.61-5.79). Patients with untreated mental health conditions (no PTT) had no increased odds of PPH+pRBC compared to those without mental health conditions. Finally, after adjusting for covariates, a positive association was found between PPT and PPH requiring pRBC transfusion and/or the use of two additional uterotonic agents beyond routine postpartum oxytocin (aOR 1.53, 95% CI: 1.35-1.73).

Conclusions

Prenatal PPT exposure is associated with increased odds of clinically significant PPH+pRBC after adjusting for other hemorrhage risk factors. Combination PPT was associated with greater odds of PPH+pRBC than monotherapy.

Predicting Intra- and Postpartum Hemorrhage through Artificial Intelligence

Background and Objectives: Intra/postpartum hemorrhage stands as a significant obstetric emergency, ranking among the top five leading causes of maternal mortality. The aim of this study was to assess the predictive performance of four machine learning algorithms for the prediction of postpartum and intrapartum hemorrhage. Materials and Methods: A prospective multicenter study was conducted, involving 203 patients with or without intra/postpartum hemorrhage within the initial 24 h postpartum. The participants were categorized into two groups: those with intra/postpartum hemorrhage (PPH) and those without PPH (control group). The PPH group was further stratified into four classes following the Advanced Trauma Life Support guidelines. Clinical data collected from these patients was included in four machine learning-based algorithms whose predictive performance was assessed. Results: The Naïve Bayes (NB) algorithm exhibited the highest accuracy in predicting PPH, boasting a sensitivity of 96.3% and an accuracy of 98.6%, with a false negative rate of 3.7%. Following closely were the Decision Tree (DT) and Random Forest (RF) algorithms, each achieving sensitivities exceeding 94% with a false negative rate of 5.9%. Regarding severity classification I, the NB and Support Vector Machine (SVM) algorithms demonstrated superior predictive capabilities, achieving a sensitivity of 96.4%, an accuracy of 92.1%, and a false negative rate of 3.6%. The most severe manifestations of HPP were most accurately predicted by the NB algorithm, with a sensitivity of 89.3%, an accuracy of 82.4%, and a false negative rate of 10.7%. Conclusions: The NB algorithm demonstrated the highest accuracy in predicting PPH. A notable discrepancy in algorithm performance was observed between mild and severe forms, with the NB and SVM algorithms displaying superior sensitivity and lower rates of false negatives, particularly for mild forms.

Risk of postpartum hemorrhage with increasing first stage labor duration

With increasing rates of postpartum hemorrhage (PPH) in high-income countries, an important clinical concern is the impact of labor duration on the risk of PPH. This study examined the relationship between increasing active first stage labor duration and PPH and explored the role of second stage labor duration and cesarean delivery (CD) in this association. Including 77,690 nulliparous women with spontaneous labor onset, first stage labor duration was defined as the time from 5 cm to 10 cm, second stage duration from 10 cm dilation to birth and PPH as estimated blood loss > 1000 ml. Using modified Poisson regression for risk ratios (RR) and confidence intervals (CI), we found a 1.5-fold (RR, 1.53; 95% CI, 1.41‒1.66) increased PPH risk when first stage of labor exceeded 12.1 h compared to the reference (< 7.7 h). Mediation analysis showed that 18.5% (95% CI, 9.7‒29.6) of the increased PPH risk with a prolonged first stage (≥ 7.7 h) was due to a prolonged second stage (> 3 h) or CD. These results suggest that including first stage duration in intrapartum assessments could improve PPH risk identification in first-time mothers with a singleton fetus in vertex presentation at full term with spontaneous labor onset.

The suboptimal clinical applicability of prognostic prediction models for severe postpartum hemorrhage: a meta-epidemiological study

OBJECTIVES

To systematically investigate clinical applicability of the current prognostic prediction models for severe postpartum hemorrhage (SPPH).

STUDY DESIGN AND SETTING

A meta-epidemiological study of prognostic prediction models was conducted for SPPH. A pre-designed structured questionnaire was adopted to extract the study characteristics, predictors and the outcome, modeling methods, predictive performance, the classification ability for high-risk individuals, and clinical use scenarios. The risk of bias among studies was assessed by the Prediction model Risk Of Bias ASsessment Tool (PROBAST).

RESULTS

Twenty-two studies containing 27 prediction models were included. The number of predictors in the final models varied from 3 to 53. However, one-third of the models (11) did not clearly specify the timing of predictor measurement. Calibration was found to be lacking in 10 (37.0%) models. Among the 20 models with an incidence rate of predicted outcomes below 15.0%, none of the models estimated the area under the precision-recall curve, and all reported positive predictive values were below 40.0%. Only two (7.4%) models specified the target clinical setting, while seven (25.9%) models clarified the intended timing of model use. Lastly, all 22 studies were deemed to be at high risk of bias.

CONCLUSION

Current SPPH prediction models have limited clinical applicability due to methodological flaws, including unclear predictor measurement, inadequate calibration assessment, and insufficient evaluation of classification ability. Additionally, there is a lack of clarity regarding the timing for model use, target users, and clinical settings. These limitations raise concerns about the reliability and usefulness of these models in real-world clinical practice.

Intrapartum Risk Factors and Prediction of Obstetric Hemorrhage-Related Morbidity

OBJECTIVE

The aim of this study was to assess whether inclusion of intrapartum risk factors improves our obstetric hemorrhage risk stratification tool in predicting obstetric hemorrhage, transfusion, and related severe morbidity.

STUDY DESIGN

This is a retrospective cohort study using all live deliveries at a single institution over a 2-year period (n = 5,332). Obstetric hemorrhage risk factors, hemorrhage burden, and severe maternal morbidity index outcomes were assessed through chart abstraction. Hemorrhage risk was assessed at (1) "time of admission" through chart abstraction and (2) "predelivery" by calculation after inclusion of all abstracted intrapartum risk factors. Admission high risk was compared with predelivery high risk for sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio in predicting obstetric hemorrhage, obstetric hemorrhage requiring transfusion, and obstetric hemorrhage-related severe morbidity. Significance levels were calculated using descriptive statistical methods including chi-squared tests and McNemar's tests.

RESULTS

The sensitivities of the risk assessment tool using admission risk classification for high-risk patients is 25% for obstetric hemorrhage, 37% for obstetric hemorrhage requiring transfusion, and 22% for obstetric hemorrhage-related severe morbidity. After intrapartum factor inclusion, the sensitivities increase to 55% for obstetric hemorrhage, 59% for obstetric hemorrhage requiring transfusion, and 47% for obstetric hemorrhage-related severe morbidity. This "predelivery" risk assessment is significantly more sensitive across all three end points (p < 0.001 for all three outcomes). While the positive likelihood ratios for obstetric hemorrhage are equal on admission and predelivery (2.10 on admission and predelivery), they increase after intrapartum factor inclusion for obstetric hemorrhage requiring transfusion and obstetric hemorrhage-related severe morbidity (on admission, 2.74 and 1.6, respectively, and predelivery: 4.57 and 3.58, respectively).

CONCLUSION

Inclusion of intrapartum risk factors increases the accuracy of this obstetric hemorrhage risk stratification tool in predicting patients requiring hemorrhage management with transfusion and obstetric hemorrhage-related severe morbidity.

KEY POINTS

· There are little data to validate intrapartum hemorrhage risk reassessment.. · Including intrapartum factors improves risk stratification for transfusion and related morbidity.. · Future research should clinically validate risk reassessment in the intrapartum period..

Is Grand Multiparity an Independent Risk Factor for Blood Transfusion?

The relation between grand multiparity and poor pregnancy outcome, especially postpartum hemorrhage and blood transfusion, has displayed inconsistent findings. Some studies have identified an increased maternal and neonatal morbidity, but the more recent literature is less clear about the risks. The objective of the study is to determine the association of grand multiparity with postpartum blood transfusion. We conducted a retrospective cohort study in a single tertiary university-affiliated medical center between 2011 and 2019. All women were categorized into one of three groups based on the number of previous deliveries: (a) nulliparous (no previous delivery), (b) multiparous (1-4 previous deliveries), and (c) grand multiparous (≥ 5 previous deliveries). We compared the demographic, clinical, and pregnancy outcomes of the study groups. The primary outcome was the need for red blood cell transfusion during the index admission. During the study period, there were 87,343 deliveries in our center. Among the study population, 36,777 (42.1%) were nulliparous, 49,072 (56.1%) were multipara, and 1494 (1.7%) were grand multiparous. Overall, 1602 women (1.8%) were treated with RBC transfusion. Cesarean delivery, macrosomia, preterm delivery, multiple gestations, antenatal anemia, thrombocytopenia, intrauterine fetal death (IUFD), and prolonged second or third stage of labor were more prevalent among women who were treated with RBC transfusion. After controlling for potential confounders, including maternal age, preterm delivery, IUFD, mode of delivery, and antenatal thrombocytopenia, grand multiparity was found to be an independent protective factor for RBC transfusion (RR = 0.2 (0.007-0.56). After controlling for cofounders, grand multiparity alone is not associated with postpartum blood transfusion.

Postpartum hemorrhage in electronic health records: risk factors at admission and in-hospital occurrence

Objective

Postpartum hemorrhage (PPH) is the leading cause of maternal death globally. Therefore, prevention strategies have been created. The study aimed to evaluate the occurrence of PPH and its risk factors after implementing a risk stratification at admission in a teaching hospital.

Methods

A retrospective cohort involving a database of SISMATER® electronic medical record. Classification in low, medium, or high risk for PPH was performed through data filled out by the obstetrician-assistant. PPH frequency was calculated, compared among these groups and associated with the risk factors.

Results

The prevalence of PPH was 6.8%, 131 among 1,936 women. Sixty-eight (51.9%) of them occurred in the high-risk group, 30 (22.9%) in the medium-risk and 33 (25.2%) in the low-risk group. The adjusted-odds ratio (OR) for PPH were analyzed using a confidence interval (95% CI) and was significantly higher in who presented multiple pregnancy (OR 2.88, 95% CI 1.28 to 6.49), active bleeding on admission (OR 6.12, 95% CI 1.20 to 4.65), non-cephalic presentation (OR 2.36, 95% CI 1.20 to 4.65), retained placenta (OR 9.39, 95% CI 2.90 to 30.46) and placental abruption (OR 6.95, 95% CI 2.06 to 23.48). Vaginal delivery figured out as a protective factor (OR 0.58, 95% CI 0.34 to 0.98).

Conclusion

Prediction of PPH is still a challenge since its unpredictable factor arrangements. The fact that the analysis did not demonstrate a relationship between risk category and frequency of PPH could be attributable to the efficacy of the strategy: Women classified as "high-risk" received adequate medical care, consequently.

Association of adverse outcomes with three-tiered risk assessment tool for obstetrical hemorrhage

BACKGROUND

Guidelines promote stratification for the risk for postpartum hemorrhage among parturients, although the evidence for the associated differential morbidity among the groups remains inconsistent among published reports.

OBJECTIVE

Using the California Maternal Quality Care Collaborative schema modified by the American College of Obstetrics and Gynecology, we compared the composite maternal hemorrhagic outcome and the composite neonatal adverse outcome among singletons who were categorized after delivery by the researchers as low-, medium-, or high-risk for postpartum hemorrhage. We hypothesized that the composite outcomes would be significantly different among the individuals in the different 3-tiered categories.

STUDY DESIGN

This was a retrospective cohort study of all singleton parturients with a gestational age of at least 14 weeks who delivered at a single site within 1 year. The composite maternal hemorrhagic outcome included any of the following: estimated blood loss ≥1000 mL, use of uterotonics (excluding prophylactic oxytocin) or Bakri balloon, surgical management of postpartum hemorrhage, blood transfusion, hysterectomy, thromboembolism, admission to the intensive care unit, or maternal death. The composite neonatal adverse outcome included Apgar score <7 at 5 minutes, birth injury, bronchopulmonary dysplasia, intraventricular hemorrhage, neonatal seizure, sepsis, ventilation > 6 hrs., brachial plexus palsy, hypoxic-ischemic encephalopathy, or neonatal death. Multivariable Poisson regression models with robust error variance were used to estimate the adjusted relative risks with 95% confidence intervals.

RESULTS

Of the 4544 deliveries in the study period, 4404 (96.7%) met the inclusion criteria, and among them, 1745 (39.6%) were categorized as low, 1376 (31.2%) as medium, and 1283 (29.1%) as high risk. Overall, 941 (21.4%) participants experienced the composite maternal hemorrhagic outcome with 285 (16.4%) of those being in the low-risk group, 319 (23.2%) in the medium-risk group, and 337 (26.3%) in the high-risk group. Among all parturients, 95.7% in the low-, 89.4% in the medium-, and 85.3% in the high-risk group neither had an estimated blood loss or a quantified blood loss ≥1000 mL nor were transfused. After multivariable adjustment and when compared with the low-risk group, there was a significantly higher risk for the composite maternal hemorrhagic outcome in the medium-risk group (adjusted relative risk, 1.23; 95% confidence interval, 1.05-1.43) and in the high-risk group (adjusted relative risk, 1.51; 95% confidence interval, 1.31-1.75). Overall, 366 newborns (8.4%) developed the composite neonatal adverse outcome with 76 (4.2%) in of those being in the low-risk group, 153 (11.3%) in the medium-risk group, and 140 (11.1%) in the high-risk group. After multivariable adjustment and when compared with the low-risk group, there were no significant differences in the composite neonatal adverse outcome in the medium- (adjusted relative risk, 1.27; 95% confidence interval, 0.97-1.68) or the high-risk group (adjusted relative risk, 1.29; 95% confidence interval, 0.98-1.68).

CONCLUSION

Although 8 of 10 parturients categorized as high risk neither had blood loss ≥1000 mL nor underwent transfusion, the risk stratification provides information regarding the composite maternal hemorrhagic outcome.

Peripartum Maternal Admission to the Intensive Care Unit: An Observational Study over a 15-Year Period at a Tertiary Center in Austria

Peripartum maternal admission to the intensive care unit is challenging for anesthesiologists, obstetricians, and all personnel involved. An understanding of altered maternal physiology, fetal considerations, and acute peripartum emergencies is required to ensure adequate maternal and neonatal outcomes. In this study, we analyzed data of peripartum maternal admissions to the intensive care unit at our large tertiary referral center in order to define trends and changes over time. This study retrospectively analyzed maternal morbidity, admission diagnoses, treatments, and outcomes of women with peripartum admission to the intensive care unit at our tertiary care center over a 15-year period. We found that patient characteristics and admission diagnoses remained remarkably consistent over the observational period; however, there was a significant increase in postpartum hemorrhage (r = 0.200, p < 0.001) and cesarean hysterectomy (r = 0.117, p = 0.027) over time. Moreover, we found a reduction in preterm births (r = -0.154, p = 0.004) and a decreased peripartum neonatal intensive care unit admission rate (r = -0.153, p = 0.006) among women who were transferred to the intensive care unit. Based on our long-term observational data, there is consistent need for intensive care in obstetrics due to a small number of different etiologies. Specialized training for the predominant diagnoses involved as well as multidisciplinary care of the affected patients are both warranted.

Oxytocin receptor DNA methylation is associated with exogenous oxytocin needs during parturition and postpartum hemorrhage

BACKGROUND

The oxytocin receptor gene (OXTR) is regulated, in part, by DNA methylation. This mechanism has implications for uterine contractility during labor and for prevention or treatment of postpartum hemorrhage, an important contributor to global maternal morbidity and mortality.

METHODS

We measured and compared the level of OXTR DNA methylation between matched blood and uterine myometrium to evaluate blood as an indicator of uterine methylation status using targeted pyrosequencing and sites from the Illumina EPIC Array. Next, we tested for OXTR DNA methylation differences in blood between individuals who experienced a postpartum hemorrhage arising from uterine atony and matched controls following vaginal birth. Bivariate statistical tests, generalized linear modeling and Poisson regression were used in the analyses.

RESULTS

Here we show a significant positive correlation between blood and uterine DNA methylation levels at several OXTR loci. Females with higher OXTR DNA methylation in blood had required significantly more exogenous oxytocin during parturition. With higher DNA methylation, those who had oxytocin administered during labor had significantly greater relative risk for postpartum hemorrhage (IRR 2.95, 95% CI 1.53-5.71).

CONCLUSIONS

We provide evidence that epigenetic variability in OXTR is associated with the amount of oxytocin administered during parturition and moderates subsequent postpartum hemorrhage. Methylation can be measured using a peripheral tissue, suggesting potential use in identifying individuals susceptible to postpartum hemorrhage. Future studies are needed to quantify myometrial gene expression in connection with OXTR methylation.

The reporting of prognostic prediction models for obstetric care was poor: a cross-sectional survey of 10-year publications

BACKGROUND

To investigate the reporting of prognostic prediction model studies in obstetric care through a cross-sectional survey design.

METHODS

PubMed was searched to identify prognostic prediction model studies in obstetric care published from January 2011 to December 2020. The quality of reporting was assessed by the TRIPOD checklist. The overall adherence by study and the adherence by item were calculated separately, and linear regression analysis was conducted to explore the association between overall adherence and prespecified study characteristics.

RESULTS

A total of 121 studies were included, while no study completely adhered to the TRIPOD. The results showed that the overall adherence was poor (median 46.4%), and no significant improvement was observed after the release of the TRIPOD (43.9 to 46.7%). Studies including both model development and external validation had higher reporting quality versus those including model development only (68.1% vs. 44.8%). Among the 37 items required by the TRIPOD, 10 items were reported adequately with an adherence rate over of 80%, and the remaining 27 items had an adherence rate ranging from 2.5 to 79.3%. In addition, 11 items had a report rate lower than 25.0% and even covered key methodological aspects, including blinding assessment of predictors (2.5%), methods for model-building procedures (4.5%) and predictor handling (13.5%), how to use the model (13.5%), and presentation of model performance (14.4%).

CONCLUSIONS

In a 10-year span, prognostic prediction studies in obstetric care continued to be poorly reported and did not improve even after the release of the TRIPOD checklist. Substantial efforts are warranted to improve the reporting of obstetric prognostic prediction models, particularly those that adhere to the TRIPOD checklist are highly desirable.

Patient Blood Management programs for post-partum hemorrhage

Patient blood management (PBM) strategies aim to maintain hemoglobin concentration, optimize hemostasis, and minimize blood loss to improve patient outcomes. Because postpartum hemorrhage (PPH) is a leading cause of maternal mortality and blood product utilization, PBM principles can be applied in its therapeutic approach. First, pre-operative identification of risk factors for PPH and identification of peri-delivery anemia should be conducted. Iron supplementation should be used to optimize hemoglobin concentration before delivery; it can also be used to treat anemia in the postpartum period after severe PPH. Both acute normovolemic hemodilution and intraoperative cell salvage can be effective techniques to reduce allogeneic blood transfusion during or after surgical procedures. Furthermore, these strategies appear to be safe when used in the pregnant population.

Oxytocin receptor single nucleotide polymorphism predicts atony-related postpartum hemorrhage

BACKGROUND

Postpartum hemorrhage remains a key contributor to overall maternal morbidity in the United States. Current clinical assessment methods used to predict postpartum hemorrhage are unable to prospectively identify about 40% of hemorrhage cases. Oxytocin is a first-line pharmaceutical for preventing and treating postpartum hemorrhage, which acts through oxytocin receptors on uterine myocytes. Existing research indicates that oxytocin function is subject to variation, influenced in part by differences in the DNA sequence within the oxytocin receptor gene. One variant, rs53576, has been shown to be associated with variable responses to exogenous oxytocin when administered during psychological research studies. How this variant may influence myometrial oxytocin response in the setting of third stage labor has not been studied. We tested for differences in the frequency of the oxytocin receptor genotype at rs53576 in relationship to the severity of blood loss among a sample of individuals who experienced vaginal birth.

METHODS

A case-control prospective design was used to enroll 119 postpartum participants who underwent vaginal birth who were at least 37 weeks of gestation. Cases were defined by either a 1000 mL or greater blood loss or instances of heavier bleeding where parturients were given additional uterotonic treatment due to uterine atony. Controls were matched to cases on primiparity and labor induction status. Genotype was measured from a maternal blood sample obtained during the 2^nd postpartum month from 95 participants. Statistical analysis included bivariate tests and generalized linear and Poisson regression modeling.

RESULTS

The distribution of the genotype across the sample of 95 participants was 40% GG (n = 38), 50.5% AG (n = 48) and 9.5% AA (n = 9). Blood loss of 1000 mL or greater occurred at a rate of 7.9% for GG, 12.5% for AG and 55.6% for AA participants (p = 0.005). Multivariable models demonstrated A-carriers (versus GG) had 275.2 mL higher blood loss (95% CI 96.9-453.4, p < 0.01) controlling for parity, intrapartum oxytocin, self-reported ancestry, active management of third stage or genital tract lacerations. Furthermore, A-carrier individuals had a 79% higher risk for needing at least one second-line treatment (RR = 1.79, 95% CI = 1.08-2.95) controlling for covariates. Interaction models revealed that A-carriers who required no oxytocin for labor stimulation experienced 371.4 mL greater blood loss (95% CI 196.6-546.2 mL).

CONCLUSIONS

We provide evidence of a risk allele in the oxytocin receptor gene that may be involved in the development of postpartum hemorrhage among participants undergoing vaginal birth, particularly among those with fewer risk factors. The findings, if reproducible, could be useful in studying pharmacogenomic strategies for predicting, preventing or treating postpartum hemorrhage.

Latest advances in postpartum hemorrhage management

Hemorrhage is the leading cause of maternal mortality worldwide. A maternal health priority is improving how healthcare providers prevent and manage postpartum hemorrhage (PPH). Because anesthesiologists can help facilitate how hospitals develop approaches for PPH prevention and anticipatory planning, we review the potential utility of PPH risk-assessment tools, bundles, and protocols. Anesthesiologists rely on clinical and diagnostic information for initiating and evaluating medical management. Therefore, we review modalities for measuring blood loss after delivery, which includes visual, volumetric, gravimetric, and colorimetric approaches. Point-of-care technologies for assessing changes in central hemodynamics (ultrasonography) and coagulation profiles (rotational thromboelastometry and thromboelastography) are also discussed. Anesthesiologists play a critical role in the medical and transfusion management of PPH. Therefore, we review blood ordering and massive transfusion protocols, fixed-ratio vs. goal-directed transfusion approaches, coagulation changes during PPH, and the potential clinical utility of the pharmacological adjuncts, tranexamic acid, and fibrinogen concentrate.

Comparison of Clinical Efficacy and Safety between Misoprostol and Oxytocin in the Prevention of Postpartum Hemorrhage: A Meta-Analysis

In order to systematically evaluate the clinical efficacy and safety of misoprostol versus oxytocin in the prevention of postpartum hemorrhage, this paper provides evidence-based reference for clinical medication, computerized retrieval of Chinese biomedical literature database (CBM), PubMed, Embase, Cochrane Library, and clinical trials. The retrieval period is from the establishment of each database to October 1, 2021. Published randomized controlled trials (RCTS) are included in this study. The literature is screened and evaluated according to inclusion and exclusion criteria, and meta-analysis is performed using RevMan 5.3 software. A total of 13 RCTS are included, with a total of 24754 parturients. The meta-analysis shows the average blood loss (SMD = 0.10, 95% CI (-0.11, 0.32), P=0.35), the time of the third stage of labor (SMD = 0, 95% CI (-0.07, 0.08), P=0.95), and blood transfusion rate (RR = 0.80, 95% CI (0.63, 1.02), P=0.07). However, the incidences of shivering (RR = 2.61, 95% CI (1.79, 0.81), P < 0.00001) and vomiting (RR = 2.78, 95% CI (1.85, 4.18), P < 0.00001) are significantly higher than those in oxytocin group. The effect of misoprostol on preventing postpartum hemorrhage is similar to that of oxytocin, but the incidence of adverse reactions is high, and the occurrence of adverse reactions should be closely watched in the use process. Due to the limitations of the included studies, multicenter, large-sample, and high-quality RCTS are still needed in the future to further verify this conclusion.