A meta-analysis of salivary estriol (sE(3)) as a means to identify women at risk for preterm birth due to fetal-placental endocrine mechanisms.
Objective: 1) Analyze overall performance of salivary estriol testing in two similarly conducted large multicenter prospective trials and 2) gain information regarding the highly integrated and regulated endocrine mechanisms controlling parturition.Methods: Meta-analysis of evaluable mother-perinate dyads from two large prospective trials was conducted. Overall, 993 pregnant women were followed prospectively with weekly saliva samples from 24 weeks to delivery.Results: 1) Occurrence of a single positive test (sE(3) >/= 2.1 ng/mL) predicted delivery prior to 37 weeks gestation (P <.0003; OR 3.4, 95% CI 1.7-6.8). If a rescreen test at one week was also >/=2.1 ng/mL (8.9% of all subjects) then relative risks of preterm birth increased to 6.86 CI (3.2-14.5) P <.0001. Having two consecutive positive tests was associated with a mean time to delivery of 2.3 weeks (negative predictive value of 97%). 2) Survival analysis of women delivering at term and preterm demonstrated that sE(3) >/= 2.1 ng/mL predicted onset of labor and birth in approximately 3 weeks:Conclusion: Meta-analysis of these two large prospective trials confirms that 1) an sE(3) >/= 2.1 ng/mL provides timely warning of a presumed endocrine signal for impending preterm and term parturition, 2) the 2-3 week mean time to delivery after a positive signal allows time for intervention, and 3) lack of a positive sE(3) signal allows a confident prediction (NPV) that delivery will not occur within 2-3 weeks.
McGregor
JA
University of Colorado Health Sciences Center, Colorado, Denver, USA
Hastings
C
Dullien
V