Fetal scalp blood sampling in labor--a review.

During the 1970s and 1980s, electronic fetal monitoring and fetal scalp blood sampling were introduced without robust evidence. With a methodical review of the published literature, and using one randomized controlled trial, seven controlled studies, nine randomized studies of various surveillance methods and data from the Danish National Birth Registry, we have assessed the usefulness of fetal scalp blood sampling as a complementary tool to improve the specificity and sensitivity of electronic cardiotocography. Based on heterogeneous studies of modest quality with somewhat inconsistent results, we conclude that fetal scalp blood sampling in conjunction with cardiotocography can reduce the risk of operative delivery. Fetal scalp blood sampling can provide additional information on fetal wellbeing and fetal reserves at a time before decisions are made concerning the need for and timing of operative delivery and the choice of anesthesia, and be an adjunct in the interpretation of cardiotocography patterns.