Placenta Previa & Fetal Growth Concerns: Understanding Ultrasound Findings

Question
My daughter is 30 weeks pregnant.  The ultrasound shows that the growth of the baby's legs are in the 3% while the head is in the 90%.  Her doctor said the placenta is attached on the upper area of her uterus rather than the normal position and the baby is not receiving all the nutrients she should.  He has started doing "stress tests" on her weekly to make sure the baby is responding correctly.  The baby is very active.  If she fails the "stress test" the doctor wants to deliver the baby prematurely.  My question is, what are the possible effects that can come from this situation to mother and child?  

Answer
If there is evidence (in any way) of "intrauterine growth restriction" we usually perform "non stress tests" (NST) weekly after 28 weeks gestation. The NST is a test that determines how the baby is reacting to its own movement. There should be a steady heartbeat with good variability and "accelerations" of heartbeat, with no dips in the heartbeat. If there is evidence of a "non reactive" NST, the baby should be delivered earlier than term. In such cases, the baby does better in the nursery than in the womb. However, the NST, if reactive, is reassuring and allows us to wait an additional week. Our goal is to try to reach 36 weeks gestation before deliving the baby, but if there is any indication of growth restriction with a non-reactive NST, delivery should be achieved sooner.