Study population
In total, 3606 labouring women who had fetal scalp sampling were primary included (Helsingborg Hospital N=523, Kristianstad Hospitals N=183, Ystad N=330, Skåne university Hospital N=1718, Östra Sahlgrenska University Hospital N=368, Söder University Hospital N=116, and Westmead Hospital, Sydney, Australia N=96). From these, 272 were excluded due to missing SSLX values, leaving 3334 for analysis. In the whole cohort 48.8% were delivered by spontaneous vaginal delivery. For fetal distress 16.1% were delivered by instrumental vaginal delivery and 18.5% by caesarean section. Of those with a pathological LP value >4.8mmol/L, 64% were in second stage of labour. Among all, and among those delivered within 25 minutes from FBS to delivery, the frequency of MA was 4.8% and 3.7% and for five minutes Apgar Score <7 the frequency was 2.6% and 2.8%, respectively.
Table 1 presents maternal and neonatal characteristics. The results are presented in two cohorts depending on the time interval between FBS to delivery. For most of the parameters there were significant differences between the two cohorts, though for MA, low AS and need for neonatal intervention, the differences were not significant.