The variation of fetal heart rhythm towards delivery

In this paper, we investigate the variation of the fetal heart rate as we approach delivery. The fetal heart rate is affected by several factors, including the uterine contractions, the amount of oxygen in blood, the sex of the fetus, etc. We isolate specific biochemical markers or other measurable characteristics and compare plots expressing the average fetal heart rate versus the time remaining until the delivery, for subjects with different values in these characteristics. Our motivation is to study the effect of different values, related to a biochemical marker or characteristic, on the heart rate of the fetus. One important observation that came out from this study is the increased discriminating power presented between different groups of subjects, appearing in the time period before the delivery, where the heart works under unusual pressure. In some cases, even though the average fetal heart rate associated to each group can not be discriminated during the early stages, the differentiation becomes possible before delivery, since the group that is expected to react better under pressure achieves to keep the heart rate in higher levels.