Fig 1.
ACTH = adrenocorticotropic hormone, DHEAs = dehydroepiandrosterone sulfate.
Fig 2.
17 OHP-C = 17-alpha hydroxyprogesterone caproate, ELISA = enzyme-linked immunosorbent assay, RIA = radioimmunoassay.
Table 1.
Demographic characteristics and baseline risk factors between women with and without CRH measurements by radioimmunoassay (N = 262).
Table 2.
Demographic characteristics and baseline risk factors of women with CRH measurements by radioimmunoassay (N = 169).
Fig 3.
Initial CRH levels at 24 and 32 weeks by delivery outcome of <37 weeks as obtained by enzyme-linked immunosorbent assay (LifeSpan Biosciences) without extraction and by radioimmunoassay with extraction.
Compared to radioimmunoassay with extraction, enzyme-linked immunosorbent assay without extraction results in assay binding interference and non-significant results. Enzyme-linked immunosorbent assay = ELISA, radioimmunoassay = RIA.
Fig 4.
Maternal plasma corticotrophin-releasing hormone level as a function of gestational age based on delivery outcome: (A) <37 weeks (blue line) versus ≥37 weeks (red line); (B) <35 weeks (blue line) versus ≥35 weeks (red line). Dotted lines represent 95% confidence intervals.
Table 3.
Corticotrophin-releasing hormone level by delivery outcome (N = 169).
Fig 5.
Receiver operator characteristic curves for plasma corticotrophin-releasing hormone levels and prior preterm birth history at 24 weeks based on delivery outcome of (A) <37 weeks and (B) <35 weeks. Green line = CRH alone. Red line = preterm birth history alone. Blue line = combination of CRH and prior preterm birth history. Area under the curve (AUC) statistics is 0.68 (95% CI 0.59–0.78) and 0.70 (95% CI 0.59–0.81) for CRH alone, at 24 (N = 169) and 32 (N = 113) weeks respectively, and 0.81 (95% CI 0.73–0.88, P = .001) for delivery <37 weeks and 0.82 (95% CI 0.74–0.91) for <35 weeks when CRH and prior preterm birth history are combined. The AUC combining CRH and prior preterm birth history is significantly different than that with CRH alone (P = .001 for <37 weeks and < .001 for <35 weeks).
Table 4.
CRH levels by RIA in unselected populations and in the current study.