It is best if the baby delivers at term (37 completed weeks of pregnancy). If the baby is born at end of 8th month it is not very bad - because you will be 35 weeks by then. However, a pre term baby has to face many problems - breathing & feeding problems, problem in maintaining temperature and as all the organs are not fully developed, other problems like jaundice after birth, bleeding into brain etc. If your doctor has advised rest - I agree with her. Bed rest does help in prolonging pregnancy. It is best to have the baby deliver as close to term, and preferably at term.