I have read a few articles that say that the benefit of bed rest has not been proven with preeclampsia, but obviously your case is a little more complicated with your strong family history of placental abruption. My OB was quick to take me off work at 29 weeks with both pregnancies, and I was on strict bed rest with my first. I do believe that bed rest benefited me with my first pregnancy. In my opinion, the improvement in your condition is relatively good proof that bed rest is a good option for you, but I'm obviously not a doctor:) It's amazing how doctors opinions differ so much.
Also, do you get short term disability from your employer? This may be something to discuss with your OB as well because if he takes you off work, puts you back on, and takes you off again, the disability company will not like this, plus there is typically a 2 week waiting period for benefits to start. This may give you a bit of an angle with your OB, if your employer offers short term disability.
Miscarriage at 8 weeks- 5/09
Abby born 37 weeks 4 days on 3/25/10 due to PIH and IUGR- 5 lbs 0.5 oz
Chemical Pregnancy lost at 5.5 weeks- 3/11
Pregnant again due Sept. 3 (now chronic hypertensive and on Labetalol)