How long should a patient continue anticoagulation and should she continue during pregnancy?

Here’s how readers responded to a You Make the Call question about anticoagulation during pregnancy.


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First, although I don’t disagree with rivaroxaban in this case, it has neither been approved nor studied formally for arterial thrombosis. Second, I have to assume that no underlying hypercoagulation disorder was present since it was not mentioned. Third, this appears to be a provoked thrombosis from her extreme exercise in combination with an anatomical defect.

Based on these assumptions, she probably needs only three months of anticoagulation followed by aspirin and close follow-up with arterial dopplers of the affected arteries to make sure no stenosis or other defect happens. With regard to further pregnancies, there are inadequate data to make a statement. How long after the pregnancy was the thrombosis? What were her antiphospholipid antibody/lupus anticoagulant studies?

Kenneth Myron Braunstein, MD
Atlanta, GA1

Six months of rivaroxaban.

David G. Savage, MD
Columbia University Medical Center
New York, NY

Presumably, the patient had no antiphospholipid antibody, so we can’t attribute her miscarriage to thrombosis. It would be nice to know the cause of her miscarriage and the findings on her infant. Artery thrombosis may be related to trauma. So, there is no evidence for a hypercoagulable state. I would treat for three months and then allow pregnancy.

George T. Conklin, MD
Diagnostic Clinic of Houston
Houston, TX

Three months of anticoagulation, then repeat vascular dopplers. If all are negative, then stop the anticoagulation.

Deborah A. Wienski, MD
Saint Louis, MO

I would recommend two to three months of anticoagulation. Since she wants to get pregnant again, l would monitor with pregnancy tests. If she becomes pregnant, then consider switching to low-molecular-weight heparin.

Marvin Diaz-Lacayo, MD
Miami, FL

I would recommend three months of anticoagulation, allowing for pregnancy after six months with prophylactic doses of low-molecular-weight heparin for six weeks postpartum.

Evan D. Slater, MD
Ventura County Medical Center
Ventura, CA

If she is off anticoagulation, then I would restart when pregnant and keep her on during pregnancy. If she is still on anticoagulation, then I would keep her on for the duration of the pregnancy.

Louis M. Aledort, MD
The Mount Sinai Medical Center
New York, NY

I would not treat her for more than three months.  I might consider acetylsalicylic acid afterward, but there are little data to support this.

Marc Lalancette, MD
Québec, Canada

This patient should not use rivaroxaban if she is contemplating pregnancy or not using contraception, because it is not recommended for pregnancy. She also should not use rivaroxaban for her arterial thrombotic event because rivaroxaban has not been well-studied for its efficacy in arterial events and is not recommended for them. In addition, there is no available reversal agent for bleeding in patients taking rivaroxaban.

It would be reasonable to treat her with a full dose of low-molecular-weight heparin (LMWH) for three months, especially if she is contemplating pregnancy and not using contraception, to be followed by 81 mg of aspirin afterward, recognizing that she will probably be at an increased risk for recurrent thrombosis because of the dual arterial system in her arm. Should she become pregnant more than three months after starting LMWH, she could be treated with either aspirin or possibly prophylactic doses of LMWH during pregnancy. Fondaparinux could be a possibility for use initially; however, it is not currently recommended for women who are pregnant or for women who are not using contraception, which I assume to be the case since the latter would have been discontinued at the time of her arterial thrombotic event.  It was not stated how many weeks out she is from her miscarriage, which may alter the recommendation somewhat based on whether her event could be considered provoked or unprovoked. These recommendations could also be altered somewhat based on whether she is still in boot camp where trauma and bleeding could be more likely, which would make the use of aspirin preferable in certain cases.

Franklin A. Bontempo, MD
Institute for Transfusion Medicine
Pittsburgh, PA

I would recommend six months of anticoagulation and venous thromboembolism prophylaxis during pregnancy.

Riton Das, MD
Port Macquarie, Australia

Look for other causes of thrombosis like Behcet’s disease. It’s hard to say if this is a provoked clot. I would suggest a minimum of three months of full-dose anticoagulation. Then it is okay to get pregnant. Start prophylactic or adjusted dose Lovenox once pregnant and continue six weeks postpartum.

Kelty R. Baker, MD
Houston, TX

I would recommend six months of rivoraxaban and low-molecular-weight heparin during next pregnancy.

Rajeev Malik, MD
Anderson Area Cancer Center
Anderson, SC

Does she smoke? Any family history? Any prior thrombotic events? The miscarriage could be related to the occult coagulopathy. I’m surprised she did not test positive for lupus anticoagulant or cardiolipin disease. Were all three types of cardiolipin and B2GP tested?

I would continue with low-molecular-weight heparin, either oral or subcutaneous. It is possible she could carry a pregnancy on treatment.

Vaughan R. Cipperly, MD

Six months.

Chrystalla Prokopiou, MD
Limassol General Hospital
Nicosia, Cyprus

I would continue rivaroxaban for four weeks and switch to 81 mg daily of aspirin before and during pregnancy.

Omer N. Koc, MD
Cleveland Clinic
Beachwood, OH

Add aspirin to anticoagulation six months before getting pregnant. Then treat with low-dose LMWH and ASA during pregnancy and continue six weeks post-partum.

Philip L. Cimo, MD
Houston, TX

I think this case is very challenging, and it falls between the cracks of “evidence-based medicine.” It requires a lot of extrapolation and “gut instincts” to manage a case like this.  There are no clinical case series or randomized clinical trials of patients at all similar to this one, nor will there ever be. Some unique aspects are that this clot was provoked (peri-partum), that it was arterial, and that there is a miscarriage history. There is also a lot of missing information that could help with decision-making, such as family history and patient preferences once risk/benefits are explained (to the limited extent they could be, and to the extent a lay person could understand).

I would be inclined to anticoagulate indefinitely – i.e., no target for stopping, but re-evaluate periodically. Because prophylactic-dose Lovenox has been found ineffective in pregnant patients with venous thromboembolism, with or without thrombophilia, I might recommend therapeutic low-molecular-weight heparin throughout pregnancy and even postpartum.

Larry Rice, MD
Houston Methodist 
Houston, TX

Rivoroxaban to be continued for three months. Pregnancy can be planned after three months.

Rajeev Kulkarni, MD
Troy, OH

This 31 year old has arterial thrombosis. She should be switched to low-molecular-weight heparin, and it should be continued for four to six weeks. It looks like the cause of arterial thrombosis could be anatomical. Because she had a miscarriage, test for lupus anticoagulant and MTHFR gene. Also, why choose rivaroxaban and not coumadin or an antiplatelet agents?

Jumana Chatiwala, MD
Regional Cancer Care Associates
Wantage, NJ

I would recommend life-long anticoagulation with dabigatran. The other option is warfarin. During pregnancy, I would recommend that she be put on fondaparinux.

Juan M. Alcantar, MD
UCLA Health
Los Angeles, CA

Facts: provoked (effort induced) deep vein thrombosis (DVT), negative thrombophilia workup. N.B. – persistent risk (vascular anomaly)? It has not been stated that dual brachial system implies an increased risk of thrombosis.

Evidence: upper limbs DVT treatment duration? No consensus, 6-9 months of anticoagulant for subclavian DVT. Vascular anomaly carries no increase risk.  Rivaroxaban not recommend in pregnancy unless highly indicated (class C).

I would recommend rivaroxaban for six to nine months. Plus, I would recommend delaying getting pregnantuntil she is off anticoagulant (i.e, 9 months). She can conceive afterward without anticoagulant; however, she needs to avoid precipitating thrombosis. Or, if getting pregnant is a priority for the patient, then she should go ahead and try to conceive. Once pregnancy test is positive, shift her to low-molecular-weight heparin (LMWH) in the first trimester, warfarin in the middle, and LMWH again in the last trimester. Continue anticoagulant up to six to eight weeks postpartum.

Ahmed Hamandi, MD
Baghdad, Iraq

I would change the anticoagulant to low-molecular-weight heparin at therapeutic dose for three months, then switch to prophylactic dose until delivery followed by rivaroxaban postpartum.

Hanan Al Wazzan

This woman developed arterial thrombosis secondary to an anatomic defect. My suggestion is a short course of oral anticoagulation (3 months) and then wait a couple of months. I would prefer to repeat hypercoagulable workup before pregnancy.  This patient would benefit from anti-aggregation during next planned pregnancy.

Pedro Lovato, MD
Hospital Regional Docente de Cajamarca
Cajamarca, Peru

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