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Venous Thrombosis: Pregnancy

One of the more discouraging aspects of practicing #midwifery within my career, is the rising maternal #death rates. We seem to have this idea that we are among the best in the world, but the United States is in fact, the WORST in perinatal outcomes of all industrialized countries. Several third world countries report better outcomes than we have for the last two decades.

One of the leading causes of material mortality is venous #thromboembolism, which has been reported by the WHO to be responsible for 14.9 percent of maternal deaths in developed countries. The United Kingdom has shared a rate of 31.1 percent of deaths related to thromboembolism in pregnancy between 2003 to 2005. Despite efforts in the United States to reduce death from thromboembolism, rates have increased by 72 percent from 1998 to 2009. This is thought to be related to the risk factors associated with venous thromboembolism overall increasing, such as advanced maternal age, major medical conditions, and #obesity.

The United Kingdom recommends more pharmacologic treatment than the guidelines currently recommended in the United States. For example, they recommend all pregnant women with a prior history to be offered pharmacologic prophylaxis, and also all those who are obese, 35 years or older, those who smoke, those with pre-eclampsia, anyone experiencing postpartum hemorrhage, and those with prolonged labor. Their deaths decreased by more than half, but of course, there are a number of variables that must be considered when implementing similar strategies in new groups.

The Safe Motherhood Initiative has offered these new recommendations:

  • Evaluation for risk of venous thromboembolism should be performed upon initial presentation to prenatal care;

  • During any hospitalization for antepartum indications;

  • During delivery of child, during the postpartum period; and

  • Upon discharge from the hospital to home.

The Joint Commission recommends that all hospitalized clients receive VTE prophylaxis or have documentation why no prophylaxis was given, but this has not been extended to pregnant clients in the past. Given the increasing incidence of VTE, the Safe Motherhood Initiative has recommended obstetrical clients be included in this recommendation.

Current Recommendations

The American Congress of Obstetricians and Gynecologists (ACOG) is one of the leading professional groups guiding management during pregnancy, and their current recommendation is to treat with either low-molecular-weight heparin or unfractionated heparin with a history of multiple VTE episodes, or having had one with high-risk for thrombophilia or with acquired thrombophilia. They also recommend prophylactic treatment for those with idiopathic VTE or VTE during pregnancy or while on oral contraception, and with family history of VTE with high-risk thrombophilia. ACOG specifically recommends not treating for first time VTE events which are provoked or with a family history of VTE with a low-risk thrombophilia.

Provoked VTEs include those which occur following orthopedic surgery, with having an indwelling line or immobilization, but does not include those which occur with estrogen-based contraception. Low-risk thrombophilias are defined as protein C or S deficiency and factor V Leiden or prothrombin gene mutation heterozygosity. High-risk thrombophilias include factor V Leiden or prothrombin gene mutation homozygosity or compound heterozygosity, and antithrombin II deficiency. Antiphospholipid antibody syndrome is the chief clinically relevant acquired thrombophilia in pregnancy.

The Safe Motherhood Initiative recommends that all patients hospitalized for an antepartum condition receive mechanical prophylaxis, and then after delivery, early mobilization and avoidance of dehydration are recommended. Pharmacologic prophylaxis with low-molecular-weight heparin or unfractionated heparin is recommended based on risk-factors.Women undergoing cesarean delivery should receive perioperative and postoperative mechanical thromboprophylaxis.

If prophylaxis was provided during pregnancy or if one has had a provoked VTE or low-risk thrombophilia with a family history of events, then prophylaxis is recommended postpartum based on ACOG and ACCP guidelines. Keep in mind, treatment doses are different than prophylaxis doses, so one must be cognizant if they are being prescribed or prescribing heparin therapy for treatment or prophylaxis. Contraindications to low-molecular weight heparin are hemophilia or other known bleeding disorder, active or threatened antenatal bleeding, thrombocytopenia, recent stroke, severe renal disease, severe liver disease, and uncontrolled hypertension.

Friedman, A. M. & Alton, M. E. (2016). Venous thromboembolism bundle: Risk assessment and prophylaxis for obstetric patients. Seminars in Perinatology, 40, 87-92.

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