Dear Dr. Krupp:
Thank-you for your question.
I'm not sure why this patient was tested for an underlying
after a single early pregnancy loss. This would not have been my
Although these events are very sad; they are very common and do
indicate any underlying pathology. Most affected women go on to
subsequent normal pregnancy without any intervention.
The data regarding the role of hereditary thrombophilia in
loss (even recurrent or late loss) is by no means definitive. This
is very much
the case with respect to the two thrombophilias you mention.
Available data are
inconsistent. Even when positive associations have been reported,
they are weak
- e.g. odds ratios of less than two in case control studies. Case
studies almost always exaggerate the strength of association so
methodologically stronger cohort studies are conducted, the
invariably becomes weaker or even disappears. The available data
convinced me that that either of the MTHFR or the prothrombin gene
associated with an increased risk of pregnancy loss.
There are no good studies demonstrating benefit to intervention
LMWH in women with a single early loss, regardless of the presence
As you have mentioned, homozygosity for the MTHFR mutation is
considered thrombophilic (in the absence of elevated homocysteine
no longer offer routine testing for this thrombophilia at our
In the absence of a personal or family history of VTE, there is
for either antepartum or postpartum prophylaxis in asymptomatic
thrombophilias other than those considered high risk (e.g.
factor V Leiden). I would not consider this patient's
thrombophilia to be
Therefore, unless I have missed something, I do not see any role
antepartum or postpartum LMWH in this setting. This patient
that she is taking appropriate folate supplementation during any
pregnancy. As for any pregnant woman, she should be vigilant for
symptoms of venous thromboembolism and seek medical attention
they occur. Her need for thrombosis prophylaxis should be
intervening risk factors develop.
I hope that is of some help,
Shannon M. Bates MDCM, MSc, FRCP(C)
Associate Professor, Department of Medicine
Director, Division of Hematology &
Discipline Director for Hematology in Laboratory Medicine
Telephone: 905 521-2100, ext. 73928
Fax: 905 521-4997