Fetal heart rate response to scalp stimulation as a test of fetal well-being in labour.

Abstract

AbstractFetal scalp stimulation with an Allis' tissue forceps applied on the baby's scalp for 15 seconds was performed in 50 patients with suspicious or ominous fetal heart rate (FHR) changes on the cardiotocographic trace in the first stage of labour. The FHR response was correlated with fetal blood pH obtained from the scalp (FBS) shortly after the test. An acceleration of the FHR of at least 15 beats above the baseline for at least 15 seconds was regarded as a positive test.Forty (80.0%) of the 50 fetuses responded with a positive test. Six (15.0%) had a preacidotic value (7.20–7.25) and 3 of them developed acidosis later and were delivered abdominally. Of the 34 with normal pH (>7.25) only one had to be delivered by a caesarean section (CS) for fetal distress later in labour. Ten (20.0%) of the 50 fetuses had a negative test; two were acidotic (<7.20) and 5 preacidotic. All had a scalp pH below 7.29. Six of them had a CS for fetal distress later in labour.These preliminary results suggest that in cases with suspicious or ominous FHR traces if the fetus responds with an acceleration to a painful stimulus the risk of fetal acidosis is small. However, the baby might be preacidotic and careful monitoring and a repeat FBS may be necessary if ominous FHR changes persist or deteriorate. If the test is negative the risk of fetal acidosis or preacidosis is considerable (70.0%). FBS is the diagnostic method of choice in cases suggestive of fetal acidosis but a scalp stimulation test might be useful in institutions without facilities for FBS and in situations where a sampling of fetal blood is difficult.