Obstetrical venous thromboembolism: Epidemiology and strategies for prophylaxis

Hypertensive Disorders of Pregnancy and Pre-Pregnancy Hypertension with Subsequent Incident Venous Thromboembolic Events

Hypertensive disorders of pregnancy (HDP) and pre-pregnancy hypertension contribute to maternal morbidity and mortality. We examined the association of HDP and pre-pregnancy hypertension with subsequent venous thromboembolic (VTE) events. The retrospective cohort study included 444,859 women with ≥1 live, singleton birth in South Carolina (2004-2016). Hospital and emergency department visit and death certificate data defined incident VTE, HDP, and pre-pregnancy hypertension. Birth certificate data also defined the exposures. Adjusted Cox proportional hazards methods modeled VTE events risk. Of the cohort, 2.6% of women had pre-pregnancy hypertension, 5.8% had HDP, 2.8% had both pre-pregnancy hypertension and HDP (both conditions), and 88.8% had neither condition. The risk of incident VTE events within one year of delivery was higher in women with HDP (hazard ratio [HR] = 1.62, 95% confidence interval [CI]: 1.15-2.29) and both conditions (HR = 2.32, 95% CI: 1.60-3.35) compared to those with neither condition as was the risk within five years for women with HDP (HR = 1.35, 95% CI: 1.13-1.60) and for women with both conditions (HR = 1.82, 95% CI: 1.50-2.20). One- and five-year risks did not differ in women with pre-pregnancy hypertension compared to women with neither condition. Compared to non-Hispanic White (NHW) women with neither condition, the incident VTE event risk was elevated within five years of delivery for NHW (HR = 1.29, 95% CI: 1.02-1.63; HR = 1.59, 95% CI: 1.16-2.17) and non-Hispanic Black (NHB; HR = 1.51, 95% CI: 1.16-2.96; HR = 2.08, 95% CI: 1.62-2.66) women with HDP and with both conditions, respectively, and for NHB women with pre-pregnancy hypertension (HR = 1.50, 95% CI: 1.09-2.07). VTE event risk was highest in women with HDP, and the event rates were higher in NHB women than in NHW women in the same exposure group.

Obstetric venous thromboembolism: Evaluation of prophylactic approach based on risk scores, D-dimer levels, and ultrasonography findings in a tertiary hospital in Japan

AIM

Pulmonary embolism remains a leading cause of maternal mortality in developed countries despite developments in venous thromboembolism prophylaxis strategies. This study aimed to evaluate the effectiveness of our approach involving risk-scoring, D-dimer level assessment, and ultrasonography for obstetric venous thromboembolism.

METHODS

This retrospective cohort study included women who delivered at 22-41 weeks of gestation in The University of Tsukuba Hospital, Japan between January and December 2020. Venous thromboembolism risk (determined according to Japanese guidelines) and D-dimer levels were evaluated within 20 weeks of gestation, 30-34 weeks of gestation, and during the pre-delivery period (36 weeks of gestation or any time before preterm delivery). Compression and color Doppler ultrasonography for lower extremity deep vein thrombosis were performed if D-dimer levels were ≥3.2 μg/mL (for those undergoing cesarean delivery, 1.0 μg/mL).

RESULTS

Of 1026 women, 6 women had deep vein thrombosis during pregnancy and 1 during the puerperium period. Pulmonary embolism was not observed. The D-dimer screening result was positive for 8 women (2%) within 20 weeks of gestation (deep vein thrombosis was confirmed in 3 of them), 87 women (10%) (no deep vein thrombosis) at 30-34 weeks of gestation, and 367 women (36%) during the pre-delivery period (asymptomatic deep vein thrombosis in one). Based on the Japanese guidelines, 1%, 11%, 33%, and 55% of women had high, intermediate, low, and no postpartum risk factors, respectively.

CONCLUSIONS

Our approach appears useful for antenatal venous thromboembolism screening in the first trimester. For postpartum prophylaxis, more cost-effective strategies are needed.

Hospital Variation and Associated Organizational Factors of Pregnancy-Related Venous Thromboembolism in China

Objective

Identifying organizational factors affecting venous thromboembolism (VTE) incidence and variations between hospitals.

Methods

From a 2019 survey of VTE and live births in 113 hospitals, organizational factors: (hospital type, characteristics, live birth number), resource availability: (D-dimer, B-scan ultrasonography of lower extremity veins, computed tomographic pulmonary angiography [CTPA], and competency: [risk assessment, use of anticoagulants and patient education], data were collected and the associations, weighted by live birth number, analyzed.

Results

Of 113 hospitals in China, 770,828 live births and 526 cases of VTE (68.2 per 100,000 live births) were reported. Nine hospitals lacked B-scan ultrasonography of lower extremity veins and 22 lacked CTPA. Prevalence rates of VTE rates were higher in general hospitals (Odds ratio [OR] = 4.251, 95% CI: 3.373-5.357), hospitals with live births < 10,000 (OR = 1.650-2.193), and hospitals without B-scan ultrasonography (OR = 1.661, 95% CI: 1.096-2.518). Hospitals implementing patient education, had a lower risk of VTE (OR = 0.296-0.374), and VTE rate decreased with the annual increase in live births.

Conclusions

Improved hospital resource availability and competency, especially patient education, is vital for reducing VTE-related maternal mortality and morbidity risk.

Missed opportunities for venous thromboembolism prophylaxis during pregnancy and the postpartum period: evidence from mainland China in 2019

BACKGROUND

Venous thromboembolism (VTE) has become one of the leading causes of maternal mortality. Thromboprophylaxis is recommended for the prevention of this condition; however, its use appears to be insufficient. Therefore, in this study, we aimed to identify the missed opportunities for VTE prophylaxis in hospitals that provide maternal healthcare in mainland China.

METHODS

In this cross-sectional survey-based study, we collected case data on pregnant and puerperal women with deep vein thrombosis and pulmonary thromboembolism from January 1st to December 31st, 2019. Demographics, obstetric information, VTE risk assessment scores, and prophylaxis-related information were recorded. Thromboprophylaxis included mobilization, mechanical methods, and treatment with anticoagulants.

RESULTS

Data corresponding to a total of 106 cases from 26 hospitals across China were collected, and 100 (94.3%) cases, 75 cases involving deep vein thrombosis and 25 cases involving pulmonary thromboembolism, were included in the final analysis. VTE occurred in 80% of the patients at the postpartum stage, while 20 patients developed the disease during the antenatal stage. Cesarean section, advanced maternal age, and obesity were the most common risk factors related to VTE during the postpartum stage, while a previous VTE-related history was a prominent risk factor among antenatal cases. Up to 75% of the patients had one or more missed opportunities for prophylaxis. The lack of the implementation of mechanical methods (60.8% vs. 24.5%, P < 0.001) and anticoagulant treatment (61.1% vs. 48.7%, P < 0.001) were more common in general hospitals compared to those of specialized hospitals. In women assessed as high-risk, anticoagulant treatment was lacking in 41 (54.7%) cases. More importantly, the lack of the implementation of mechanical methods was more common among women assessed as low-risk (56.0% vs. 38.7%, P < 0.001). Among the antenatal cases, the lack of treatment with anticoagulants (100.0% vs. 48.5%, P < 0.001) and implementation of mechanical methods (70.0% vs. 36.7%, P < 0.001) was highlighted. In addition, the lack of early mobilization was much more prominent among the PTE cases (10.5% vs. 37.5%, P < 0.001).

CONCLUSIONS

At least one prophylactic opportunity was missed in most of the enrolled Chinese women with VTE during the course of their maternal healthcare. Missed prophylactic opportunities varied with the type of hospitals, risk assessment, onset timing and disease type. Further efforts from patients, healthcare systems, and healthcare providers are needed for improving the implementation of preventative strategies.

Venous thromboembolism prophylaxis for women at risk during pregnancy and the early postnatal period

BACKGROUND

Venous thromboembolism (VTE), although rare, is a major cause of maternal mortality and morbidity. Some women are at increased risk of VTE during pregnancy and the early postnatal period (e.g. caesarean section, family history of VTE, or thrombophilia), and so prophylaxis may be considered. As some methods of prophylaxis carry risks of adverse effects, and risk of VTE is often low, benefits of thromboprophylaxis may be outweighed by harms.

OBJECTIVES

To assess the effects of thromboprophylaxis during pregnancy and the early postnatal period on the risk of venous thromboembolic disease and adverse effects in women at increased risk of VTE.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (18 October 2019). In addition, we searched ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) for unpublished, planned and ongoing trial reports (18 October 2019).

SELECTION CRITERIA

Randomised trials comparing one method of thromboprophylaxis with placebo or no treatment, or two (or more) methods of thromboprophylaxis.

DATA COLLECTION AND ANALYSIS

At least two review authors assessed trial eligibility, extracted data, assessed risk of bias, and judged certainty of evidence for selected critical outcomes (using GRADE). We conducted fixed-effect meta-analysis and reported data (all dichotomous) as summary risk ratios (RRs) with 95% confidence intervals (CIs).

MAIN RESULTS

Twenty-nine trials (involving 3839 women), overall at moderate to high risk of bias were included. Trials were conducted across the antenatal, peripartum and postnatal periods, with most in high-income countries. Interventions included types and regimens of heparin (low molecular weight heparin (LMWH) and unfractionated heparin (UFH)), hydroxyethyl starch (HES), and compression stockings or devices. Data were limited due to a small number of trials in comparisons and/or few or no events reported. All critical outcomes (assessed for comparisons of heparin versus no treatment/placebo, and LMWH versus UFH) were considered to have very low-certainty evidence, downgraded mainly for study limitations and imprecise effect estimates.  Maternal death was not reported in most studies. Antenatal (± postnatal) prophylaxis For the primary outcomes symptomatic thromboembolic events pulmonary embolism (PE) and/or deep vein thrombosis (DVT), and the critical outcome of adverse effects sufficient to stop treatment, the evidence was very uncertain.  Symptomatic thromboembolic events: - heparin versus no treatment/placebo (RR 0.39; 95% CI 0.08 to 1.98; 4 trials, 476 women; very low-certainty evidence); - LMWH versus UFH (RR 0.47; 95% CI 0.09 to 2.49; 4 trials, 404 women; very low-certainty evidence); Symptomatic PE: - heparin versus no treatment/placebo (RR 0.33; 95% CI 0.02 to 7.14; 3 trials, 187 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 287 women); Symptomatic DVT: - heparin versus no treatment/placebo (RR 0.33; 95% CI 0.04 to 3.10; 4 trials, 227 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 287 women); Adverse effects sufficient to stop treatment: - heparin versus no treatment/placebo (RR 0.49; 95% CI 0.05 to 5.31; 1 trial, 139 women; very low-certainty evidence); - LMWH versus UFH (RR 0.07; 95% CI 0.01 to 0.54; 2 trials, 226 women; very low-certainty evidence). Peripartum/postnatal prophylaxis Vaginal or caesarean birth When UFH and no treatment were compared, the effects on symptomatic thromboembolic events (RR 0.16; 95% CI 0.02 to 1.36; 1 trial, 210 women; very low-certainty evidence), symptomatic PE (RR 0.16; 95% CI 0.01 to 3.34; 1 trial, 210 women; very low-certainty evidence), and symptomatic DVT  (RR 0.27; 95% CI 0.03 to 2.55; 1 trial, 210 women; very low-certainty evidence) were very uncertain.  Maternal death and adverse effects sufficient to stop treatment were not reported. Caesarean birth Symptomatic thromboembolic events: - heparin versus no treatment/placebo (RR 1.30; 95% CI 0.39 to 4.27; 4 trials, 840 women; very low-certainty evidence); - LMWH versus UFH (RR 0.33; 95% CI 0.01 to 7.99; 3 trials, 217 women; very low-certainty evidence); Symptomatic PE: - heparin versus no treatment/placebo (RR 1.10; 95% CI 0.25 to 4.87; 4 trials, 840 women; very low-certainty evidence); - LMWH versus UFH (no events; 3 trials, 217 women);  Symptomatic DVT: - heparin versus no treatment/placebo (RR 1.30; 95% CI 0.24 to 6.94; 5 trials, 1140 women; very low-certainty evidence); LMWH versus UFH (RR 0.33; 95% CI 0.01 to 7.99; 3 trials, 217 women; very low-certainty evidence); Maternal death: - heparin versus placebo (no events, 1 trial, 300 women); Adverse effects sufficient to stop treatment: - heparin versus placebo (no events;  1 trial, 140 women). Postnatal prophylaxis No events were reported for LMWH versus no treatment/placebo for: symptomatic thromboembolic events, symptomatic PE and symptomatic DVT (all 2 trials, 58 women), or maternal death (1 trial, 24 women). Adverse effects sufficient to stop treatment were not reported. We were unable to conduct subgroup analyses due to lack of data. Sensitivity analysis including the nine studies at low risk of bias did not impact overall findings.

AUTHORS' CONCLUSIONS

The evidence is very uncertain about benefits and harms of VTE thromboprophylaxis in women during pregnancy and the early postnatal period at increased risk of VTE. Further high-quality very large-scale randomised trials are needed to determine effects of currently used treatments in women with different VTE risk factors. As sufficiently large definitive trials are unlikely to be funded, secondary data analyses based on high-quality registry data are important.

Platelet count and function in umbilical cord blood versus peripheral blood in term neonates

Platelet function in neonates is sparsely investigated. The majority of previous studies investigated platelets in umbilical cord (UC) blood rather than in peripheral blood.We included 20 term neonates and sampled UC blood and peripheral blood within 20 min and 24 h after birth. Platelet count and mean platelet volume (MPV) were measured. Platelet surface glycoproteins (GP) and platelet activation (bound fibrinogen, CD63 and p-selectin) after agonist stimulation were examined by flow cytometry. Platelet aggregation was evaluated by impedance aggregometry. The significance level was set after Bonferroni correction.Platelet count and MPV did not differ between UC and peripheral blood (p-values >0.08). Expression of platelet surface GP was similar in UC and peripheral blood (all p-values >0.02). Platelet activation was lower in UC blood than in peripheral blood for bound fibrinogen (four out of eight p-values <0.001) but did not differ for CD63 (all p-values >0.01) or P-selectin (all p-values >0.01). Platelet aggregation was significantly higher in UC than in peripheral blood (p-values <0.001).In conclusion, platelet count, MPV and expression of platelet surface GP measured in term neonatal UC blood represented that of peripheral blood. Platelet activation and aggregation in UC blood did not reflect that of peripheral blood.

Immediate postpartum management of patients with severe hypertensive disorders of pregnancy: pathophysiology guiding practice

Developing clinically-focused evidence and experience-based approaches to improve maternity care is a national priority. Safety and quality collaborative initiatives related to management of hypertensive disorders of pregnancy are vital in the implementation of improved care. We reviewed the obstetric literature to construct a concise summary of the core pathophysiologic issues, practice principles and clinical interventions which are foundational for physicians providing immediate postpartum care for patients with severe pregnancy-related hypertension (including those with eclampsia, HELLP syndrome, and superimposed preeclampsia inclusive of those with gestational hypertension that develop severe range blood pressures). While based largely upon the American College of Obstetrics and Gynecology (ACOG) Hypertension Task Force Guidelines released in 2013 as well as updated 2018 guidelines set forth by ACOG for hypertensive disorders of pregnancy, this summary goes beyond the basic safety bundles for hypertension management and lays a pathophysiologic foundation for the immediate postpartum care of patients with severe hypertensive disorders of pregnancy.

Developing a model for predicting venous thromboembolism in obese pregnant women in a national study

INTRODUCTION

Venous thromboembolism (VTE) in pregnancy and postpartum is a leading cause of maternal morbidity and mortality in developed countries, where obesity is a known risk for this complication. Current guidelines vary in which patients qualify for VTE prophylaxis, precluding a uniform approach for management. We sought to derive a risk prediction model for VTE in obese pregnant women.

MATERIALS AND METHODS

We performed a retrospective cohort analysis using the Consortium on Safe Labor (CSL) database. Women ages 16-45 who were pregnant with singletons and had an obese body mass index (>30 kg/m²) were included in our study population. Multivariable logistic regression was used in order to identify predictors of venous thromboembolism.

RESULTS

Of the 83,500 women who met inclusion criteria, on average women were 27.8 years old, 38.6 weeks gestation, with body mass index of 35.8, and cesarean delivery incidence of 35.2%. 109 women (0.13%) experienced a VTE event. Independent predictors of VTE in our final multivariable predictive model included: mode of delivery, body mass index, pregestational diabetes, chronic heart disease, preeclampsia, blood transfusion (intrapartum or postpartum), prenatal history of thromboembolic disorder, and postpartum maternal length of stay. A receiver operating characteristic curve was developed to assess the model; area under the curve was 0.826.

CONCLUSIONS

We developed a strong predictive model using a large, retrospective database to distinguish risk of VTE in obese pregnant women, which may provide the foundation for future protocol development of obstetrical thromboprophylaxis in obese women.

Establishment of a risk assessment tool for pregnancy-associated venous thromboembolism and its clinical application: protocol for a prospective observational study in Beijing

BACKGROUND

The risk of venous thromboembolism (VTE) during pregnancy and puerperal periods is significantly higher than during the non-pregnant period and is one of the major causes of maternal mortality. Developed countries have promulgated guidelines for risk assessment and prevention of maternal VTE, and standardized management has led to a significant reduction in maternal mortality. However, there is a paucity of relevant research related to pregnancy and puerperal VTE in China.

METHODS/DESIGN

We will perform a prospective cohort study and recruit 13,000 pregnant women from 2018 to 2020 in Beijing, China. VTE risk assessment will be conducted using the Royal College of Obstetricians and Gynaecologists (RCOG) pregnancy and puerperal VTE risk-assessment-scoring tool during early and late pregnancy, as well as during the puerperal period. Venous ultrasonography of lower extremities, routine blood tests, and coagulation parameters will be examined. These VTE risk assessments will be performed again if patients have VTE-related symptoms during their pregnancies, or if any of the following occur: (1) patients are hospitalized over 7 days due to any pregnancy complications; (2) patients are placed under strict bed rest for ≥ 3 days to prevent miscarriage. For patients with a confirmed diagnosis of VTE, treatment and follow-up plans will be decided jointly by the obstetricians, vascular surgeons, and pulmonologists. All patients in the study will be followed up by dedicated healthcare providers for up to 42 days postpartum. Statistical analyses will be performed to test the feasibility of the RCOG scoring tool for the Chinese population. The RCOG scoring tool will then be revised based upon the characteristics of the Chinese population, and the revised assessment scoring tool will then be tested in the cohort to evaluate its efficacy. Finally, a pregnancy and puerperal VTE risk-assessment tool will be proposed based on our study results.

DISCUSSION

This study will establish a preliminary VTE risk-assessment tool that is applicable to pregnant and puerperal women in China and provide guidelines for further thrombophylactic interventions. Furthermore, we wish to draw increased attention to pregnancy-associated VTE to reduce VTE-related mortality.

TRIAL REGISTRATION

Chi CTR1800015848 (04/24/2018).

Venous thromboembolism as a cause of severe maternal morbidity and mortality in the United States

In the U.S., deaths due to pulmonary embolism (PE) account for 9.2% of all pregnancy-related deaths or approximately 1.5 deaths per 100,000 live births. Maternal deaths and maternal morbidity due to PE are more common among women who deliver by cesarean section. In the past decade, the clinical community has increasingly adopted venous thromboembolism (VTE) guidelines and thromboprophylaxis recommendations for pregnant women. Although deep vein thrombosis rates have decreased during this time-period, PE rates have remained relatively unchanged in pregnancy hospitalizations and as a cause of maternal mortality. Changes in the health profile of women who become pregnant, particularly due to maternal age and co-morbidities, needs more attention to better understand the impact of VTE risk during pregnancy and the postpartum period.

Guidelines for Antenatal and Preoperative care in Cesarean Delivery: Enhanced Recovery After Surgery Society Recommendations (Part 1)

This Enhanced Recovery After Surgery (ERAS) Guideline for perioperative care in cesarean delivery will provide best practice, evidenced-based, recommendations for preoperative, intraoperative, and postoperative phases with, primarily, a maternal focus. The focused pathway process for scheduled and unscheduled cesarean delivery for this ERAS Cesarean Delivery Guideline will consider from the time from decision to operate (starting with the 30-60 minutes before skin incision) to hospital discharge. The literature search (1966-2017) used Embase and PubMed to search medical subject headings that included "Cesarean Section," "Cesarean Section," "Cesarean Section Delivery" and all pre- and intraoperative ERAS items. Study selection allowed titles and abstracts to be screened by individual reviewers to identify potentially relevant articles. Metaanalyses, systematic reviews, randomized controlled studies, nonrandomized controlled studies, reviews, and case series were considered for each individual topic. Quality assessment and data analyses that evaluated the quality of evidence and recommendations were evaluated according to the Grading of Recommendations, Assessment, Development and Evaluation system, as used and described in previous ERAS Guidelines. The ERAS Cesarean Delivery Guideline/Pathway has created a maternal focused pathway (for scheduled and unscheduled surgery starting from 30-60 minutes before skin incision to maternal discharge) with ERAS cesarean delivery consensus recommendations preoperative elements (anesthetic medications, fasting, carbohydrate supplementation, prophylactic antibiotics/skin preparation, ), intraoperative elements (anesthetic management, maternal hypothermia prevention, surgical technique, hysterotomy creation and closure, management of peritoneum, subcutaneous space, and skin closure), perioperative fluid management, and postoperative elements (chewing gum, management of nausea and vomiting, analgesia, timing of food intake, glucose management, antithrombotic prophylaxis, timing of ambulation, urinary management, and timing of maternal and neonate discharge). Limited topics for optimized care and for antenatal education and counselling and the immediate neonatal needs at delivery are discussed. Strong recommendations for element use were given for preoperative (antenatal education and counselling, use of antacids and histamine, H2 receptor antagonists, 2-hour fasting and small meal within 6 hours surgery, antimicrobial prophylaxis and skin preparation/chlorhexidine-alcohol), intraoperative (regional anesthesia, prevention of maternal hypothermia [forced warm air, warmed intravenous fluids, room temperature]), perioperative (fluid management for euvolemia and neonatal immediate care needs that include delayed cord clamping), and postoperative (fluid management to prevent nausea and vomiting, antiemetic use, analgesia with nonsteroidal antiinflammatory drugs/paracetamol, regular diet within 2 hours, tight capillary glucose control, pneumatic compression stocking for venous thromboembolism prophylaxis, immediate removal of urinary catheter). Recommendations against the element use were made for preoperative (maternal sedation, bowel preparation), intraoperative (neonatal oral suctioning or increased inspired oxygen), and postoperative (heparin should not be used routinely venous thromboembolism prophylaxis). Because these ERAS cesarean delivery pathway recommendations (elements/processes) are studied, implemented, audited, evaluated, and optimized by the maternity care teams, this will create an opportunity for the focused and optimized areas of care research with further enhanced care and recommendation.

Venous Thromboembolism Prophylaxis During Antepartum Admissions and Postpartum Readmissions

OBJECTIVE

To characterize the use of venous thromboembolism prophylaxis during antepartum and postpartum hospitalizations in the United States.

METHODS

A retrospective cohort study using the Perspective database was performed to analyze temporal trends of mechanical and pharmacologic venous thromboembolism prophylaxis for patients hospitalized for antepartum and postpartum indications between 2006 and 2015. Delivery hospitalizations were excluded. The association between use of prophylaxis and medical and obstetric risk factors as well as patient demographic and hospital characteristics was evaluated with unadjusted and adjusted models accounting for demographic, hospital and medical, and obstetric risk factors.

RESULTS

A total of 622,740 antepartum and 105,361 postpartum readmissions were identified and included in the analysis. Between 2006 and 2015, use of venous thromboembolism prophylaxis increased from 18.5% to 38.7% for antepartum admissions (adjusted risk ratio [RR] 1.94, 95% CI 1.88-2.01) and from 22.5% to 30.6% for postpartum readmissions (adjusted RR 1.31, 95% CI 1.21-1.43). Among women readmitted postpartum, 56.4% of prophylaxis was pharmacologic and 43.6% was mechanical. For antepartum admissions, 87.2% of prophylaxis was mechanical and 12.8% was pharmacologic. Significant regional and hospital-level variation was noted with prophylaxis most common in the South. In both unadjusted and unadjusted analyses, use of venous thromboembolism prophylaxis was more common for women with thrombophilia, ovarian hyperstimulation syndrome, a history of venous thromboembolism, and prolonged hospitalization. Factors associated with decreased rates of prophylaxis included hyperemesis and postpartum endometritis.

CONCLUSION

Although antepartum and postpartum venous thromboembolism prophylaxis is becoming increasingly common, particularly in the setting of medical or obstetric risk factors, use of prophylaxis varies regionally and on a hospital level. Some risk factors for venous thromboembolism were associated with lower rates of prophylaxis. The heterogeneity of clinical approaches to venous thromboembolism prophylaxis for these patient populations may represent an opportunity to perform outcomes research to further clarify best practices.