Low-Dose Aspirin During Pregnancy: Risks & Considerations

Question
Age: 31, children: 1 live birth, 1 miscarriage (blighted ovum) at
12 weeks, currently 5 weeks pregnant (LMP: 12/19/05).  

Question:  My2 1/2 y.o. son has mild cerebral palsy (we're
seeing genetics for thromophillic event vs neuronal migrational
disorder).  He has a mildly elevated factor VIII, "indeterminate"
anticardiolipin Ab, IgM, !n (12L) and low Protein C (52L).  My
husband and I are awaiting results of our thromophillic panels
and in the mean time, my genetic's m.d has recommended that I
take a low dose of daily aspirin (81mg).  I'm nervous about this.  
What is the lowest dose possible to take without harmful side
effects to the fetus yet adequately anticoagulating my blood on
the chance that my thrombophillic panels come back abnormal.  
Any information you can provide would be greatly appreciated.  
Any foods I should avoid while taking aspirin?  

Answer
If your thrombophilic panel shows that you are at risk for thromboembolic phenomena, it may be necessary to take heparin and aspirin during the pregnancy. I would not start it until the tests come back. It is still controversial to use low dose aspirin during pregnancy due to the risk of bleeding and of premature closure of the ductus arteriosus in the baby. On the other hand, women with antiphospholipid syndrome do benefit from treatment with heparin and low dose aspirin during pregnancy. Suddessful pregnancy rates for these women are 70-75% compared with less than 50% for untreated patients. If the tests show that you do indeed have some evidence of thromboembolic risk, I would also recommend the aspirin (and heparin). I'm sure that your doctor will discuss all of this with you.