Dr Bronwyn Moore (gynaecologist) answers:
The two probelms are separate from each other. Antiphospholipid syndrome (APLS) is associated with poor obstetric outcomes including preterm delivery, miscarriage and stillbirth. There are also material risks including DVT, pulmonary embolus and severe pre-eclampsia. The aspirin has an antiplatelet action to reduce your blood cells "stickness" and should be used with an injectable blood thinner in pregnancy. With these drugs the outcome of pregnancy is significantly improved. A low placenta may cause bleeding in your pregnancy and if this is severe may result in preterm delivery. You are already 29 weeks and even if your baby were deliveerd now, he should do well in an appropriate neonatal unit.
A low palcenta may also cause abnormal positions of your baby in utero and that may mean that you need to deliver your baby by c-section. The two together may result in your doctor suggesting delivery before your due date, and I feel that this would be appropriate for your situation.