[Normal values for the R peak amplitude in the abdominal fetal ECG at term and their significance for the detection of fetal postmaturity syndrome].
This is a retrospective study on 2 008 abdominal fetal ECGs of 1 005 patients. Standard values of R-peaks in the fetal ECG depending on the weeks of pregnancy are figured out. For the first time these standard values are shown on a percentile table and a percentile curve group. Depending on this standard values the frequency of fetal postmaturity is calculated. If the 90th percentile values for the R-peaks amplitude has been exceeded, then there is a 32% probability of severe fetal postmaturity in the pregnancy time of more than 290 days p.m., and a 20% probability if the pregnancy time is between 270-290 days p.m. Meconium has been observed in 44% of all cases, if pregnancy was prolonged more than 290 days p.m. and if in addition the R-amplitude was higher than the 90. percentile value. The abdominal fetal ECG therefore is a good additional method in cases of prolonged pregnancy to recognize fetal postmaturity.