Chapter 4 Results - etheses Repository

Accuracy of estriol in asymptomatic women
For predicting spontaneous preterm birth before 37 weeks’ gestation, a single salivary estriol
testing had an LR+ 2.55 (95% CI 1.73 - 3.77) and LR- of 0.56 (95% CI 0.35 - 0.89) while a
repeat test, where one positive result indicated positivity had an LR+ of 5.46 (95% CI 3.18 -
9.40) and LR- of 0.61 (95% CI 0.43 - 0.88) (Figure 47). 192 For predicting spontaneous
preterm birth before 37 weeks’ gestation, serum estriol test had a range of LR+ from 0.76
(95% CI 0.58 - 1.00) to 2.17 (95% CI 1.33 - 3.53) and LR- from 0.77 (95% CI 0.60 - 0.99) to
1.02 (95% CI 1.00 - 1.04) (Figure 47). 152;165 Estimates from Yaron et al 165 and Kim et al 193
represented the largest higher quality studies of the reference standard, with commonly used
thresholds of 0.75 MoM and 0.5 MoM respectively. There was no study which reported
spontaneous preterm birth before 34 weeks’ gestation. Individual accuracy results can be
found in Table 30.
Accuracy of estriol in symptomatic women
For predicting spontaneous preterm birth before 37 weeks’ gestation, salivary estriol had an
LR+ of 2.31 (95% CI 1.64 - 3.24) and LR- of 0.40 (95% CI 0.20 - 0.79) (Figure 47). 191 There
is no study evaluating serum estriol in predicting spontaneous preterm birth in symptomatic
women. Individual accuracy results can be found in Table 30.
95