Faculty Bibliography

In recent years, state obstetric quality and maternal safety initiatives have led efforts to reduce maternal risk and improve maternal safety. A priority of many of these collaboratives has been to disseminate and implement safety bundles focusing on leading causes of maternal mortality including venous thromboembolism. In 2013, the Safe Motherhood Initiative (SMI), a quality improvement effort led by ACOG District II in New York State, began developing a VTE bundle reviewed available clinical evidence, practice guidelines, and protocols and assessed how hospitals with varying resources could implement standardized approaches to obstetric thromboembolism prophylaxis. This bundle was subsequently released for implementation in New York State's hospitals with support from SMI. The purpose of this review is to characterize, from the perspective of a state safety leadership collaborative, the resources that were most critical in assisting individual hospitals in (i) determining which VTE prophylaxis strategies would be adopted, and (ii) operationalizing implementation.

The purpose of this review is to explore the role of hospital systems in reliably providing high quality obstetric venous thromboembolism (VTE) prophylaxis focusing on the example of the Kaiser Permanente Southern California hospital system. While providers ultimately administer thromboprophylaxis on a patient-by-patient basis, hospital-level protocols, practices, and resources may be the most important determinants of whether a patient receives appropriate care. In comparison to the complex maternal and fetal emergencies that obstetricians are routinely called on to manage, VTE prophylaxis can often be simplified and integrated into the workflow, making decision-making time efficient and straightforward for the provider. Not having protocols (i.e. the provider being on their own) is associated with desired management occurring in only 40% of cases. Enhanced VTE protocols with complementary strategies to encourage use and identification of oversights addressed in real time can result in appropriate care in >90% of cases.

Outcomes research on obstetric venous thromboembolism (VTE) involves a number of major challenges. While obstetric VTE, including deep vein thrombosis and pulmonary embolism, is relatively common on a population basis, diagnoses during pregnancy are relatively rare in comparison to high-risk scenarios such as orthopedic surgery. This review characterizes outcomes research on obstetric VTE with a focus on strengths, limitations, and appropriate inferences from existing research. It is divided into four sections. First, evidence regarding validity of diagnosis codes for VTE in administrative data is reviewed. Second, limitations of both clinical research and administrative-data study models are analyzed. Third, examples of high-quality obstetric VTE research from the literature and opportunities for improved research in the future are reviewed. Fourth, future directions for research are explored.

How to best reduce maternal risk from obstetric venous thromboembolism (VTE) is a relatively controversial topic. In comparison, for other leading causes of maternal mortality and severe morbidity such as obstetric hemorrhage and hypertension, there is general agreement on recommendations. While obstetric VTE poses a unique epidemiological and public health challenge, a number of recommendations related to care improvement and patient safety can be made. This edition of Seminars in Perinatology focuses on (i) overview of clinical research and epidemiology that can serve as a basis for informed decision making regarding VTE prophylaxis strategies, (ii) VTE prophylaxis implementation from a leadership perspective, (iii) future directions for research on obstetric VTE, and (iv) critical care management of obstetric VTE.

In 2018 two documents were released from major anesthesia societies, the American Society for Regional Anesthesia (ASRA) and the Society for Obstetric Anesthesia and Perinatology (SOAP), to aid anesthesiologists in decision making regarding neuraxial procedures for obstetric patients receiving anticoagulation. For obstetrical providers seeking to provide appropriate inpatient thromboprophylaxis while also maximizing access to neuraxial anesthesia, awareness of these recommendations may be critically important. In comparison to anesthesiologists in other medical and surgical scenarios, obstetric anesthesiologists are more likely to be called upon to administer anesthesia urgently or emergently. Approximately one-third of women in the United States deliver by cesarean, and while many of these procedures will be scheduled, many others will be performed for an urgent indication where timing of delivery cannot be anticipated precisely. The purpose of this review is to summarize key clinical obstetric anesthesia management points related to anticoagulation for the obstetrician so that both VTE prophylaxis and access to neuraxial anesthesia can be optimized.

OBJECTIVE:To characterize probabilities of vaginal delivery based on second-stage duration along with maternal and neonatal risks for women undergoing labor after cesarean delivery. METHODS:This unplanned secondary analysis of the Maternal-Fetal Medicine Units Cesarean Registry, a prospective observational cohort, assessed outcomes in women with a prior uterine scar and included women with a previous cesarean delivery without prior vaginal delivery who reached the second stage of labor. The primary outcome was mode of delivery by second-stage duration. Secondary outcomes included assessment of individual adverse maternal (chorioamnionitis, atony, endometritis, hysterectomy, uterine rupture or dehiscence, and red cell transfusion) and neonatal (cord pH less than 7.10, Apgar score less than 6 at 5 minutes, neonatal intensive care unit admission, and ventilatory support) outcomes. RESULTS:Of 4,579 women with a previous cesarean delivery who reached the second stage of labor, 4,147 (90.6%) delivered vaginally. As second stage increased, successful vaginal delivery rates decreased: 97.3% at less than 1 hour (95% CI 96.6-97.9%), 91.5% at 1 to less than 2 hours (95% CI 89.8-93.1%), 78.5% at 2 to less than 3 hours (95% CI 74.5-82.1%), 62.3% at 3 to less than 4 hours (95% CI 55.2-69.1%), and 45.6% at 4 hours or greater (95% CI 37.7-53.7%). Risk of all adverse maternal outcomes increased with the length of the second stage. Specifically, risk of uterine rupture or dehiscence increased with second-stage length from less than 1 hour (0.7%), 1 to less than 2 hours (1.4%), 2 to less than 3 hours (1.5%), to 3 hours or greater (3.1%) (P<.001 for differential risk across the second stage). Risk of neonatal outcomes did not differ significantly by second-stage length. CONCLUSION:Although many women with a longer second stage (greater than 3 hours) will achieve successful vaginal delivery, these patients may be at increased risk for adverse maternal outcomes and should have close observation of fetal heart rate monitoring, maternal vital signs, and symptoms suggestive of uterine rupture or dehiscence.

OBJECTIVE:To evaluate temporal trends in use of antihypertensive medications during delivery hospitalizations complicated by preeclampsia and risk of maternal stroke over the same time period. METHODS:The Perspective database was used to perform a retrospective cohort study evaluating antihypertensive drugs dispensed during delivery hospitalizations complicated by preeclampsia from 2006 to the first quarter of 2015. Medications evaluated included nifedipine, hydralazine, and oral and intravenous labetalol. Adjusted models for receipt of antihypertensive agents accounting for demographic and hospital factors were created. Hospital-level rates of antihypertensive administration for women with severe preeclampsia were analyzed. Risk of stroke during delivery hospitalization was evaluated. RESULTS:A total of 239,454 patients with preeclampsia were included in the analysis including 126,595 women with mild, 31,628 with superimposed, and 81,231 with severe preeclampsia. Overall, 105,409 women received a hypertensive agent. From 2006 to 2014, for all patients with preeclampsia, receipt of oral labetalol increased from 20.3% to 31.4%, intravenous labetalol from 13.3% to 21.4%, hydralazine from 12.8% to 16.9%, nifedipine from 15.0% to 18.2%, and more than one medication from 16.5% to 25.8%. The proportion of patients with preeclampsia receiving any antihypertensive medication rose from 37.8% in 2006 to 49.4% in 2015. In adjusted models, temporal trends retained significance. Rates of antihypertensive administration for severe preeclampsia varied significantly by hospital. For severe preeclampsia, the risk for stroke decreased from 13.5 per 10,000 deliveries in 2006-2008 (n=27) to 9.7 in 2009-2011 (n=25) to 6.0 in 2012-2014 (n=20) (P=.02). CONCLUSION:Use of multiple antihypertensive agents to treat preeclamptic women increased over the study period for women with mild, superimposed, and severe preeclampsia. There was substantial hospital variation in use of antihypertensive agents. This trend was associated with decreased risk of maternal stroke.