Pregnancy-related deaths in the United States have risen from a low of 7.2 per 100,000 live births in 1987 to a high of 17.3 per 100,000 live births in 2013, according to the Centers for Disease Control and Prevention (CDC) Pregnancy Mortality Surveillance System.1 Alarmingly, such deaths among African-American women are more than 3 times as common as among white women (40.4 vs 12.1 per 100,000).
Relative causes of maternal mortality have also changed. Between 1991 and 1999, pulmonary embolism (PE) was the leading cause of pregnancy-related deaths, accounting for 21% of cases.2 However, by 2013, cardiovascular disease and cardiomyopathies accounted for a quarter of all maternal deaths while PE accounted for only 9.2% of cases. Paradoxically, between 1994 and 2009, the rate of venous thromboembolism (VTE) among antepartum and postpartum hospitalizations increased by 17% and 47%, respectively, and the rate of maternal hospitalizations associated with PE increased 128%.3 While this increase was concordant with dramatic increases in major risk factors for VTE (including obesity, advanced maternal age at delivery, and medical comorbidities), it was inversely proportional to the actual maternal deaths ascribable to PE over that period. We can only speculate on explanations for this contradiction such as increased diagnoses of deep venous thrombi and small PEs with the advent of improved imaging techniques, increased clinical awareness and surveillance, more effective treatments, or simply better documentation. But lest we become complacent, we must acknowledge that any death from PE is at least theoretically preventable.
While it is too early to appreciate its full impact, there is evidence that the American College of Obstetricians and Gynecologists (ACOG) recommendation for universal use of peri- and postoperative pneumatic compression devices in all women undergoing cesarean delivery4 may be having an impact on PE-associated mortality. Clark and associates reported that there was an 86% decline in postoperative deaths due to PE from 7 per 458,097 cesarean births in 2006-2007 to 1 in 465,880 cesarean births in 2007–2012 following the introduction of such devices for all cesarean births beginning in 2007 in Hospital Corporation of America obstetrical facilities.5 But can we do better? A recent consensus statement from a patient safety group opines that we can.
More aggressive pharmacological thromboprophylaxis needed
The National Partnership for Maternal Safety (NPMS) was created to improve maternal health and safety in the United States and consists of multiple stakeholder organizations.6 This group recently proposed an aggressive patient safety bundle to reduce occurrence of VTE in pregnancy.7 The NPMS authors note that beyond universal use of pneumatic compression devices for cesarean delivery, current ACOG recommendations are rather limited in regard to use of prophylactic post-cesarean anticoagulation, stating it should be applied when “additional,” largely unspecified, VTE risks are present. Similarly, for hospitalized antepartum patients and patients who are having vaginal deliveries, ACOG recommends either prophylactic or therapeutic anticoagulation only when there is “significant risk” of VTE during pregnancy or the puerperium (ie, among patients with antiphospholipid antibody (APA) syndrome or inherited thrombophilias).4
In contrast, the Royal College of Obstetricians and Gynaecologists (RCOG) has taken a far more aggressive posture on the use of pharmacological thromboprophylaxis that has been accompanied by a corresponding temporal reduction in VTE deaths in the United Kingdom from 1.94 deaths per 100,000 births in 2003–2005 to 1.01 deaths per 100,000 births from 2001 to 2013. The 2015 RCOG guidelines recommend use of a rather complex scoring system with subsequent antenatal or postpartum thromboprophylaxis using low-molecular-weight heparin (LMWH) based on the score.8 The RCOG also recommends that practitioners consider thromboprophylaxis for all antepartum hospitalizations in the absence of specific contraindications and opines that all patients in labor who require a cesarean delivery and all patients with a BMI >40 kg/m2 receive 10 days of postnatal thromboprophylaxis.