PREGNANCY
THROMBOPROPHYLAXIS
|
Agents for
Thromboprophylaxis
|
Warfarin should
Arch Intern
Med. 2000 Jan 24;160(2):191-6.
Anticoagulation of pregnant women with mechanical heart valves: a systematic
review of the literature.
Chan WS, Anand S, Ginsberg JS.
Department of Medicine, Women's College Hospital, Toronto, Ontario, Canada.
Background:
The management of women with prosthetic heart valves during
pregnancy poses a particular challenge as there are no available controlled
clinical trials to provide guidelines for effective antithrombotic therapy.
Oral anticoagulants such as warfarin sodium cause fetal embryopathy;
subcutaneous administration of heparin sodium has been reported to be
ineffective in preventing thromboembolic complications.
Objectives:
To
identify the risks of maternal and fetal complications in women with
mechanical heart valves treated with different anticoagulation regimens
during pregnancy.
Methods:
We performed a systematic review of the
literature to determine pooled estimates of maternal and fetal risks
associated with the 3 commonly used approaches: (1) oral anticoagulants (OA)
throughout pregnancy, (2) replacing OA with heparin in the first trimester
(from 6-12 weeks' gestation), and (3) heparin use throughout pregnancy.
Fetal outcomes included spontaneous abortions and fetopathic effects, and
maternal outcomes were major bleeding, thromboembolic complications, and
death.
Results:
The use of OA throughout pregnancy is associated with
warfarin embryopathy in 6.4% (95% confidence interval [CI], 4.6%-8.9%) of
livebirths. The substitution of heparin at or prior to 6 weeks, and
continued until 12 weeks, eliminated this risk. Overall risks for fetal
wastage (spontaneous abortion, stillbirths, and neonatal deaths) were
similar in women treated with OA throughout, compared with women treated
with heparin in the first trimester. Maternal mortality was 2.9% (95% CI,
1.9%-4.2%). Maj or bleeding events occurred in 2.5% (95% CI, 1.7%-3.5%) of
all pregnancies, most at the time of delivery. The regimen associated with
the lowest risk of valve thrombosis (3.9%; 95% CI, 2.9-5.9%) was the use of
OA throughout; using heparin only between 6 and 12 weeks' gestation was
associated with an increased risk of valve thrombosis (9.2%; 95% CI,
5.9%-13.9%).
Conclusions:
Thromboembolic prophylaxis of women with
mechanical heart valves during pregnancy is best achieved with OA; however,
this increases the risk of fetal embryopathy. Substituting OA with heparin
between 6 and 12 weeks reduces the risk of fetopathic effects, but with an
increased risk of thromboembolic complications. The use of low-dose heparin
is definitely inadequate; the use of adjusted-dose heparin warrants
aggressive monitoring and appropriate dose adjustment. Large prospective
trials to determine the best regimen for these women are needed.
Do you have an unanswered women's health question?
Please let us have your general question on our
NEW FORUM
/ MESSAGE BOARDS facility and we will try
to answer it for you. I am sure that you will appreciate that we cannot offer advice on the management of an individual's specific problem.
DISCLAIMER
The aim of this web site is to provide a general guide and it is
not intended as a substitute for a consultation with an appropriate specialist
in respect of individual care and treatment.
Thank you for your visiting us at 2womenshealth.com.
This is the personal website of David A Viniker MD FRCOG, Consultant Obstetrician and Gynaecologist at Whipps Cross University Hospital, London.
I do hope that you find the answers to your questions in the patient information and medical advice provided.
If you still have unanswered questions, please consider entering them into one of our forums and I will try to assist you.
   
| 
