A friend who is an OB/GYN sent me this article:
Warfarin called reasonable approach
Anticoagulation in Pregnant Heart Valve Patients
Bruce Jancin
Denver Bureau
SNOWMASS, COLO. ? Continued use of warfarin throughout pregnancy is a reasonable management strategy in selected women with a prosthetic heart valve, Dr. Carole A. Warnes said at a conference sponsored by the American College of Cardiology.
Appropriate candidates are women on lower-dose warfarin before pregnancy and at high risk for a thromboembolic event during pregnancy, either because of a history of prior events or because they have an older tilting-disk mechanical valve in the mitral position, said Dr. Warnes, professor of medicine at the Mayo Clinic, Rochester, Minn.
Unfractionated heparin is a less attractive option in these high-risk patients. It's a much less effective antithrombotic agent than warfarin during pregnancy she added.
The chief downside of warfarin use in pregnancy is the risk of embryopathy with fetal exposure during weeks 6-9. But there is evidence to suggest this risk is probably dose-related. One showed no embryopathy in 33 exposed fetuses whose mothers were on 5 mg/day or less of warfarin, compared with a 9% incidence of warfarin embryopathy in 25 fetuses whose mothers were on higher doses. However, this study was a retrospective case series, and there have been no controlled trials to guide management of thromboembolic risk in pregnant patients with prosthetic valves.
While warfarin dosage requirements can change frequently during pregnancy, a woman who is well controlled on 5 mg/day or less prior to pregnancy usually won't need more than 5 mg/day during pregnancy, she said.
Warfarin embryopathy is marked by mental retardation, optic atrophy, nasal hypoplasia, and cataracts. But the risk of warfarin embryopathy following fetal exposure is often overstated in the literature. Rates quoted in various series range from 4% to 28.6%.
What few people realize, however, is that rates at the high end are confined to chondrodysplasia punctata, the most common manifestation of warfarin embryopathy. This clinically insignificant skeletal abnormality is apparent only on x-ray and is irrelevant to a child's development.
It is advisable to discontinue warfarin near term and switch to intravenous heparin to an activated partial thromboplastin time of 2.5-3.5. If warfarin is on board during labor and delivery, fetal or maternal hemorrhage can result.
Warfarin is listed in the Physicians' Desk Reference as contraindicated in pregnancy. Conversely, the American College of Cardiology?American Heart Association guidelines specifically advise against the use of low-molecular-weight heparin (LMWH) in pregnant women with prosthetic valves.
In addition, last year Aventis Pharmaceuticals added to its enoxaparin product label a warning against the drug's use for thromboprophylaxis in patients with prosthetic heart valves, regardless of pregnancy status.
The American College of Obstetricians and Gynecologists followed with an advisory that LMWH is safe in pregnancy except in women with mechanical prosthetic heart valves, where the drug is not recommended.
The Aventis product labeling change prompted a multidisciplinary expert panel to convene last year to review in detail the scientific evidence. In mid-October the Anticoagulation in Prosthetic Valves and Pregnancy Consensus Report Panel criticized the labeling change as ?unsubstantiated? and concluded that of the three available options for anticoagulation in pregnant women with mechanical heart valves?warfarin, LMWH, and unfractionated heparin?LMWH ?offered the best option of three suboptimal choices.?
Blanche, What calcium do you think I should take and will ask my PCP....Bonnie
