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The warfarin option after delivery

Whilst warfarin is not used during pregnancy; it is a viable option once delivery has taken place. A week after delivery, the treatment may be changed from injectable heparins to oral warfarin tablets. The concern about the risk of warfarin to the baby is, of course, no longer there.

Warfarin is also safe with breast-feeding. However, not every patient is keen to switch to warfarin. Warfarin medication necessarily entails regular and frequent blood tests to ensure that the correct dose is being taken. For heparin this is not necessary.

Since heparin is self-administered, many mothers consider this to be a significant advantage, which avoids the inconvenience of frequent hospital visits. This is reinforced by the availability of once-daily injections. Ideally, mothers are given the options in the postnatal period.

Breast-feeding and warfarin or heparin treatment

There is no problem with breast-feeding for a woman on either warfarin or heparin. They are both safe. The low molecular-weight heparins (LMWH) are also safe.

Arterial thrombosis and pregnancy

Arterial thrombosis is a problem that is almost exclusive to one group of patients: Those with artificial (prosthetic) heart valves. If a person has heart valve disease, the defective valves may be replaced by mechanical valves. In such a case, life-long anticoagulant medication is instituted. This is because the presence of artificial valves poses a significant risk of thrombosis and embolism.

For a non-pregnant woman, in almost all cases, the long-term anticoagulation takes the form of warfarin tablets, which are taken daily. If the affected woman becomes pregnant, medication will be changed to heparin, usually one of the low-molecular weight preparations (LMWH) such as Fragmin, Innohep or Clexane, for the duration of the pregnancy.

If there is any laxity with the anticoagulation regime, arterial thrombosis is a real danger, with potentially life-threatening consequences.

Some physicians argue that, in cases of prosthetic heart valves, it is justified to continue using warfarin anticoagulation rather than risk switching to heparin. This is a very contentious argument and, while it has its merits, most experts hold that a switch to heparin is hardly ever problematic and can be smoothly phased in. The only difficulty may be in persuading a patient who is used to painless tablets to come round to the idea of having to put up with injections for forty weeks, give or take.