Risk Factors for Atonic Postpartum Hemorrhage: A Systematic Review and Meta-analysis

Risk assessment tools to predict postpartum hemorrhage

Postpartum hemorrhage (PPH) is a leading cause of maternal morbidity and mortality, and accurate risk assessments may allow providers to anticipate and prevent serious hemorrhage-related adverse events. Multiple category-based tools have been developed by national societies through expert consensus, and these tools assign low, medium, or high risk of hemorrhage based on a review of each patient's risk factors. Validation studies of these tools show varying performance, with a wide range of positive and negative predictive values. Risk prediction models for PPH have been developed and studied, and these models offer the advantage of more nuanced and individualized prediction. However, there are no published studies demonstrating external validation or successful clinical use of such models. Future work should include refinement of these models, study of best practices for implementation, and ultimately linkage of prediction to improved patient outcomes.

The role of fibrinogen in postpartum hemorrhage

Postpartum hemorrhage (PPH) is the leading cause of maternal death worldwide (WHO), with almost 60000 deaths annually. Pregnancy is a prothrombotic state with increased levels of several coagulation factors to protect the parturient from bleeding problems during delivery. Fibrinogen has a significant role in coagulation and bleeding. Studies have pointed out that lower fibrinogen levels before delivery, but also at the initiation of PPH, are predictive of major hemorrhage. Early, the goal-directed fibrinogen concentrate therapy might be very useful in a subgroup of patients with serious PPH. This review aims to summarize the current literature on fibrinogen during PPH.

Epidemiology and definition of PPH worldwide

Postpartum/peripartum hemorrhage (PPH) is an obstetric emergency complicating 1-10% of all deliveries and is a leading cause of maternal mortality and morbidity worldwide. However, the incidence of PPH differs widely according to the definition and criteria used, the way of measuring postpartum blood loss, and the population being studied with the highest numbers in developing countries. Despite all the significant progress in healthcare, the incidence of PPH is rising due to an incomplete implementation of guidelines, resulting in treatment delays and suboptimal care. A consensus clinical definition of PPH is needed to enable awareness, early recognition, and initiation of appropriate intensive treatment. Unfortunately, the most used definition of PPH based on blood loss ≥500 ml after delivery suffers from inaccuracies in blood loss quantification and is not clinically relevant in most cases, as the amount of blood loss does not fully reflect the severity of bleeding.

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.

Risk factors and recurrence of cause-specific postpartum hemorrhage: A population-based study

OBJECTIVE

To explore risk profiles of the different types of postpartum hemorrhage (PPH >500ml or severe PPH >1500ml) and their recurrence risks in a subsequent delivery.

METHODS

With data from The Medical Birth Registry of Norway and Statistics Norway we performed a population-based cohort study including all singleton deliveries in Norway from 1967-2017. Multilevel logistic regression was used to calculate odds ratio (OR), with 95% confidence interval (CI), with different PPH types (PPH >500ml or PPH >1500ml (severe PPH) combined with retained placenta, uterine atony, obstetric trauma, dystocia, or undefined cause) as outcomes.

RESULT

We identified 277 746 PPH cases of a total of 3 003 025 births (9.3%) from 1967 to 2017. Retained placenta (and/or membranes) was most often registered as severe PPH (29.3%). Maternal, fetal, and obstetric characteristics showed different associations with the PPH types. Male sex of the neonate was associated with reduced risk of PPH. This effect was strongest on PPH due to retained placenta (adjusted OR, (aOR): 0.80, 95% CI 0.78-0.82), atony (aOR 0.92, 95% CI: 0.90-0.93) and PPH with undefined cause (aOR 0.96, 95% CI: 0.95-0.97). Previous cesarean section showed a strong association with PPH due to dystocia (aOR of 13.2, 95% CI: 12.5-13.9). Recurrence risks were highest for the same type: PPH associated with dystocia (aOR: 6.8, 95% CI: 6.3-7.4), retained placenta and/or membranes (aOR: 5.9, 95% CI: 5.5-6.4), atony (aOR: 4.0, 95% CI: 3.8-4.2), obstetric trauma (aOR: 3.9, 95% CI: 3.5-4.3) and PPH of undefined cause (aOR: 2.2, 95% CI: 2.1-2.3).

CONCLUSION

Maternal, fetal and obstetric characteristics had differential effects on types of PPH. Recurrence differed considerably between PPH types. Retained placenta was most frequently registered with severe PPH, and showed strongest effect of sex; delivery of a boy was associated with lower risk of PPH. Previous cesarean increased the risk of PPH due to dystocia.

Hospital-level variation in rates of postpartum hemorrhage in California

BACKGROUND

To examine the extent of hospital-level variation in risk-adjusted rates of postpartum hemorrhage (PPH).

STUDY DESIGN AND METHODS

We performed a cross-sectional study examining live births in 257 California hospitals between 2011 and 2015 using linked birth certificate and maternal discharge data. PPH was measured using International Classification of Diseases Codes version 9. Mixed-effects logistic regression models were used to examine the presence and extent of hospital-level variation in PPH before and after adjustment for patient-level risk factors and select hospital characteristics (teaching status and annual delivery volume). Risk-adjusted rates of PPH were estimated for each hospital. The extent of hospital variation was evaluated using the median odds ratio (MOR) and intraclass correlation coefficient (ICC).

RESULTS

Our study cohort comprised 1,904,479 women who had a live birth delivery hospitalization at 247 hospitals. The median, lowest, and highest hospital-specific rates of PPH were 3.48%, 0.54%, and 12.0%, respectively. Similar rates were observed after adjustment for patient and hospital factors (3.44%, 0.60%, and 11.48%). After adjustment, the proportion of the total variation in PPH rates attributable to the hospital was low, with a MOR of 2.02 (95% confidence interval [CI]: 1.89-2.15) and ICC of 14.3% (95% CI: 11.9%-16.3%).

DISCUSSION

Wide variability exists in the rate of PPH across hospitals in California, not attributable to patient factors, hospital teaching status, and hospital annual delivery volume. Determining whether differences in hospital quality of care explain the unaccounted-for variation in hospital-level PPH rates should be a public health priority.

Intrapartum magnesium sulfate exposure and obstetric hemorrhage risk

BACKGROUND

The gold standard intrapartum treatment for preeclampsia with severe features is magnesium sulfate in order to provide prophylaxis against eclampsia. However, though magnesium sulfate is known to have a relaxant effect on uterine muscle, there have been variable reports in the literature in regard to the association between magnesium and obstetric hemorrhage (OBH).

OBJECTIVE

We aim to compare OBH incidence in patients with hypertensive disease of pregnancy (HDP) with or without exposure to intrapartum magnesium sulfate.

METHODS

We performed a retrospective cohort study of all deliveries at our institution associated with a diagnosis of hypertensive disease of pregnancy (HDP) (e.g. chronic and gestational hypertension, preeclampsia with or without severe features, eclampsia, or HELLP) from January 1, 2018 to December 31, 2019. The category of HDP diagnosis was determined by a detailed chart review by trained chart abstractors. The primary outcome was total quantitative blood loss (QBL) and the rate of obstetric hemorrhage. Secondary outcomes included a composite of obstetric hemorrhage-related maternal morbidity outcomes (OBH-M), the individual composite components and the incidence of additional hemorrhage-related interventions (e.g. uterotonics and surgical interventions). We also examined the same primary and secondary outcomes in a stratified analysis based on delivery mode (i.e. vaginal deliveries only and cesarean deliveries only).

RESULTS

Of 791 patients with a diagnosis of HDP, 411 patients received magnesium sulfate for eclampsia prophylaxis and 380 patients did not receive magnesium sulfate. For all delivery modes, there was a significantly higher QBL (p < .01), increased rate of OBH (p = .04) and increased OBH-M (p < .01) in deliveries associated with intrapartum exposure to magnesium compared to those without. However, our stratified analysis by delivery mode demonstrated that magnesium-related hemorrhage risk only persisted for vaginal deliveries (QBL p < .01; OBH aOR 1.47, 95% CI: 0.75-2.85; OBH-M aOR 1.47, 95% CI 1.00-7.55) with no significant hemorrhage-related differences among cesareans with or without magnesium exposure (QBL p = .51; OBH aOR 1.45, 95% CI: 0.85-2.47; OBH-M 1.50 95% CI: 0.70-3.23).

CONCLUSION

Intrapartum exposure to magnesium sulfate use was associated with an increase in QBL and risk of OBH-M in vaginal deliveries, but not associated with any hemorrhage-related outcome differences in cesarean deliveries. More research is needed to explore the effects of hypertensive disease, magnesium exposure, and delivery mode on obstetric hemorrhage risk.

Is there a relationship between plasma, cytokine concentrations, and the subsequent risk of postpartum hemorrhage?

BACKGROUND

Postpartum hemorrhage remains the leading cause of maternal mortality. However, there is an insufficient understanding of atonic postpartum hemorrhage. Uterine atony is the most common cause of postpartum hemorrhage. Although an association between myometrium inflammatory cytokines and atonic postpartum hemorrhage has been demonstrated preliminarily, it is not clinically useful in predicting postpartum hemorrhage. Plasma is more readily available, and the assessment of its inflammatory status is more relevant to biological markers of postpartum hemorrhage and might explain the pathophysiology of atonic postpartum hemorrhage.

OBJECTIVE

Our objective was to examine changes in maternal plasma cytokines in women with atonic postpartum hemorrhage.

STUDY DESIGN

This was a retrospective longitudinal case-control study of pregnant women with singleton gestations at term undergoing vaginal delivery. Cases were women with atonic postpartum hemorrhage, and 1:1 propensity-score matching was used to match the control group. Maternal plasma was collected in the first trimester, early third trimester, and late third trimester, and multiplex Luminex assay was used to determine the cytokine concentrations. Multivariate logistic regressions were used to determine the association between maternal cytokines at different stages of pregnancy and atonic postpartum hemorrhage.

RESULTS

A total of 36 pregnant women met the clinical diagnostic criteria for atonic postpartum hemorrhage, and 36 patients without postpartum hemorrhage were matched as the control group. Concentrations were lower for most cytokines in the atonic postpartum hemorrhage group in the first and early third trimester. However, in the late third trimester, higher plasma concentrations of basic fibroblast growth factor, interleukin-1 alpha, interleukin-1 beta, interleukin-1 receptor antagonist, interleukin-2 receptor alpha, interleukin-16, interleukin-18, macrophage colony stimulating factor, macrophage inflammatory protein-1 alpha, beta-nerve growth factor, tumor necrosis factor-related apoptosis-induced ligand, and stem cell factor were significantly associated with increased risk of atonic postpartum hemorrhage. Multiple testing correction showed that basic fibroblast growth factor (P<.001; fold change [FC]=1.16), macrophage inflammatory protein-1 alpha (P<.001; FC=1.15), and stem cell factor (P=.001; FC=1.25) had the most significant difference (P<.001). The prediction model of atonic postpartum hemorrhage constructed by these significantly changed cytokines had a high predictive efficiency (area under the curve, 0.84; sensitivity, 0.78; specificity, 0.83; +likelihood ratio, 4.66; -likelihood ratio, 0.27).

CONCLUSION

Higher concentrations of maternal plasma cytokines in the late third trimester are associated with high risk of subsequent atonic postpartum hemorrhage. These indicators may be potential biomarkers for predicting atonic 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.

Uterine atony

PURPOSE OF REVIEW

Postpartum hemorrhage (PPH) is the leading preventable cause of maternal morbidity and mortality worldwide. Uterine atony is identified as the underlying etiology in up to 80% of PPH. This serves as a contemporary review of the epidemiology, risk factors, pathophysiology, and treatment of uterine atony.

RECENT FINDINGS

Rates of postpartum hemorrhage continue to rise worldwide with the largest fraction attributed to uterine atony. A simple 0-10 numerical rating score for uterine tone was recently validated for use during cesarean delivery and may allow for more standardized assessment in clinical and research settings. The optimal prophylactic dose of oxytocin differs depending on the patient population, but less than 5 units and as low as a fraction of one unit is needed for PPH prevention, with an increased requirements within that range for cesarean birth, those on magnesium, and advanced maternal age. Carbetocin is an appropriate alternative to oxytocin. Misoprostol shows limited to no efficacy for uterine atony in recent studies. Several uncontrolled case studies demonstrate novel mechanical and surgical interventions for treating uterine atony.

SUMMARY

There is a critical, unmet need for contemporary, controlled studies to address the increasing threat of atonic PPH.

Maternal, Perinatal and Neonatal Outcomes of Triplet Pregnancies According to Chorionicity: A Systematic Review of the Literature and Meta-Analysis

Triplet pregnancies are rare events that affect approximately 93 in 100,000 deliveries in the world, especially due to the increased use of assisted reproductive techniques and older maternal age. Triplet pregnancies are associated with a higher risk of fetal and maternal morbidity and mortality compared to twins and singletons. Chorionicity has been proposed as a major determinant of perinatal and maternal outcomes in triplet pregnancies, although further evidence is needed to clarify the extent and real influence of this factor. Thus, the aim of this study was to conduct a systematic review of the literature and a meta-analysis of the maternal and perinatal outcomes of triplet pregnancies, evaluating how chorionicity may influence these results. A total of 46 studies with 43,653 triplet pregnancies and 128,145 live births were included. Among the main results of our study, we found a broad spectrum of fetal and maternal complications, especially in the group of monochorionic and dichorionic pregnancies. Risk of admission to NICU, respiratory distress, sepsis, necrotizing enterocolitis, perinatal and intrauterine mortality were all found to be higher in non-TCTA pregnancies than in TCTA pregnancies. To date, our meta-analysis includes the largest population sample and number of studies conducted in this field, evaluating a wide variety of outcome measures. The heterogeneity and retrospective design of the studies included in our research represent the main limitations of this review. More evidence is needed to fully assess outcome measures that could not be studied in this review due to scarcity of publications or insufficient sample size.

Development and Validation of Prognostic Nomogram for Postpartum Hemorrhage After Vaginal Delivery: A Retrospective Cohort Study in China

Background

Postpartum hemorrhage (PPH) is a common complication following vaginal delivery and in severe cases can lead to maternal death. A straightforward predictive model is required to enable prenatal evaluations by obstetricians to prevent PPH complications.

Methods

Data of patients who delivered vaginally after 37 weeks of gestation were retrospectively collected from the medical database at Shengjing Hospital of China Medical University for the period 2016 to 2020. PPH was defined as blood loss of 500 mL or more within 24 h of delivery, and important independent prognostic factors were determined using univariate and multivariate logistic regression analyses to construct nomograms regarding PPH.

Results

A total of 24,833 patients who delivered vaginally were included in this study. The training cohort included 22,302 patients who delivered between 2016 and 2019 and the external validation cohort included 2,531 patients who delivered during 2020. Nomogram was created using data such as age, race, occupation, parity, gestational weeks, labor time, neonatal weight, analgesic delivery, gestational diabetes mellitus, premature rupture of membranes, anemia, hypertension, adenomyosis, and placental adhesion. The nomogram has good predictive power and clinical practicality through the analysis of the area under the curve and decision curve analysis. Internal verification was performed on the nomogram for PPH, demonstrating consistency between the nomogram's predicted probability and actual probability.

Conclusions

The developed and validatable nomogram is a good predictor of PPH in vaginal delivery and can be used in clinical practice to guide obstetricians to administer preventive therapies before delivery.

Obstetrical Hemorrhage

Obstetric hemorrhage is a leading cause of morbidity and mortality. Prevention includes identifying patients with risk factors and actively managing the third stage of labor. The anesthesiologist should be ready to manage hemorrhage with general strategies as well as strategies tailored to the specific cause of hemorrhage. Both neuraxial anesthesia and general anesthesia are appropriate in different situations. Treatments proven to be effective include increasing the oxytocin infusion, administering tranexamic acid early, guiding transfusion with point-of-care tests, and using cell salvage. Utilization of protocols and checklists within systems that encourage effective communication between teams should be implemented.

Enhanced Recovery after Surgery: Cesarean Delivery

This review summarizes the importance of enhanced recovery after surgery (ERAS) implementation for cesarean deliveries (CDs) and explores ERAS elements shared with the non-obstetric surgical population. The Society for Obstetric Anesthesia and Perinatology (SOAP) consensus statement on ERAS for CD is used as a template for the discussion. Suggested areas for research to improve our understanding of ERAS in the obstetric population are delineated. Strategies and examples of anesthesia-specific protocol elements are included.

Postpartum hemorrhage: Moving from response to prevention for Alaska Native mothers

OBJECTIVE

To identify risk factors for postpartum hemorrhage in a population of Alaska Native women.

METHODS

A case-control study of 384 women (128 cases, 256 controls) delivering between August 1, 2018, and July 31, 2019, was conducted at a Level III maternal referral center for Alaska Native women in Alaska. Risk factors were assessed via retrospective chart review, and bivariate and conditional regression analyses were conducted to determine odds ratios (ORs) between women with and without postpartum hemorrhage.

RESULTS

Body mass index ≥40 (OR 2.6, 95% confidence interval [CI] 1.4-4.5), antepartum bleeding (OR 6.3, 95% CI 1.2-31.6), previous postpartum hemorrhage (OR 5, 95% CI 2.6-9.8), suspected macrosomia (OR 2.7, 95% CI 1.4-5.3), macrosomia with birthweight ≥4000 g (OR 3.1, 95% CI 1.8-5.3), pre-eclampsia with magnesium sulfate (OR 4.0, 95% CI 2.0-8.0), length of third stage of labor >20 min (OR 2.2, 95% CI 1.1-4.4), oxytocin use >12 h (OR 5.4, 95% CI 2.0-14.6), residence in a rural community (OR 2.2, 95% CI 1.4-3.6), and vitamin D supplementation (OR 1.7, 95% CI 1.1-2.6) were associated with greater risk of postpartum hemorrhage.

CONCLUSION

Analysis of clinical and geographic risk factors for postpartum hemorrhage in Alaska Native women identified important targets for prevention.

Postpartum haemorrhage trends in Sweden using the Robson ten group classification system: a population-based cohort study

OBJECTIVE

To examine postpartum haemorrhage (PPH) trends in Sweden using the Robson classification system.

DESIGN

Population-based cohort study.

SETTING

Sweden.

POPULATION

Deliveries in 2000-2016, classified as Robson groups 1-5 (singleton pregnancies in vertex presentation, from gestational weeks 37+0; n = 1 590 178).

METHODS

We examined temporal trends in PPH between 2000 and 2016 overall, and within each Robson group, and performed logistic regression to examine the influence of changes in risk factors (maternal, comorbidity, obstetric practice and infant factors) over time.

MAIN OUTCOME MEASURES

Postpartum haemorrhage, defined as an estimated blood loss of >1000 ml.

RESULTS

The overall PPH rate increased from 5.4 to 7.3%, corresponding to a 37% (OR 1.37, 95% CI 1.32-1.42) increase over time. Rates varied between Robson groups, ranging from 4.5% in group 3 to 14.3% in group 4b. Increasing trends in PPH were found in all Robson groups except for groups 2b and 4b (prelabour caesarean deliveries). In the unstratified analysis, adjusting for maternal, comorbidity and obstetric practice factors slightly attenuated the risk of PPH in the later period (2013-2016), compared with the reference period (2000-2004; crude OR 1.26, 95% CI 1.24-1.29, adjusted OR 1.22, 95% CI 1.20-1.25). Within individual Robson groups, changes in risk factors did not explain increasing rates of PPH.

CONCLUSIONS

Postpartum haemorrhage rates varied between Robson groups. Changes in risk factors could not explain the 37% increase in PPH for women in Robson groups 1-5 in Sweden, 2000-2016.

TWEETABLE ABSTRACT

Changes in risk factors could not explain the increasing trend of PPH in Sweden, and rates of PPH varied widely between Robson groups.

Risk Factors for Postpartum Hemorrhage in a Thai-Myanmar Border Community Hospital: A Nested Case-Control Study

Postpartum hemorrhage (PPH) is a common complication of pregnancy and a global public health concern. Even though PPH risk factors were extensively studied and reported in literature, almost all studies were conducted in non-Asian countries or tertiary care centers. Our study aimed to explore relevant risk factors for PPH among pregnant women who underwent transvaginal delivery at a Thai–Myanmar border community hospital in Northern Thailand. An exploratory nested case-control study was conducted to explore risk factors for PPH. Women who delivered transvaginal births at Maesai hospital from 2014 to 2018 were included. Two PPH definitions were used, which were ≥ 500 mL and 1000 mL of estimated blood loss within 24 h after delivery. Multivariable conditional logistic regression was used to identify significant risk factors for PPH and severe PPH. Of 4774 women with vaginal births, there were 265 (5.55%) PPH cases. Eight factors were identified as independent predictors for PPH and severe PPH: elderly pregnancy, minority groups, nulliparous, previous PPH history, BMI ≥ 35 kg/m², requiring manual removal of placenta, labor augmentation, and fetal weight > 4000 gm. Apart from clinical factors, particular attention should be given to pregnant women who were minority groups as PPH risk significantly increased in this population.