NST - starting at 36 weeks

According to my Ob/Gyn, I have to take this test at my weekly visit from week 36 to the end. This is because I am considered high risk because of my age. The test involves attaching one belt to the mother's abdomen to measure fetal heart rate and another belt to measure contractions. Movement, heart rate and "reactivity" of heart rate to movement is measured for 20-30 minutes. As I lie back and stare at the computer and machine that perform the NST test, I start to formulate questions. First, "Why am I taking this test; what are they looking for?" The answer is that they are checking to make sure that the baby's oxygen levels are normal. When oxygen levels are low, the fetus may not respond normally. Low oxygen levels can often be caused by problems with the placenta or umbilical cord. Also, "What do the results mean? Will there have to be further testing?" A reactive non-stress result indicates that blood flow (and oxygen) to the fetus is adequate. A nonreactive non-stress result requires additional testing to determine whether the result is truly due to poor oxygenation, or whether there are other reasons for fetal nonreactivity (i.e. sleep patterns, certain maternal prescription or nonprescription drugs.