First-trimester maternal serum PP13 in the risk assessment for preeclampsia.

OBJECTIVE: The objective of the study was to determine whether first-trimester maternal serum placental protein 13 (PP13) concentrations can be used in the risk assessment for preeclampsia. STUDY DESIGN: This case-control study included 50 patients with preeclampsia and 250 patients with normal pregnancies. Samples were collected between 8 and 13 weeks of gestation. Serum PP13 concentrations were measured by immunoassay and expressed as medians and multiples of the median (MoM) for gestational age. Sensitivity and specificity were derived from receiver-operating characteristic curve analysis. RESULTS: (1) Serum PP13 concentration in the first trimester was significantly lower in patients who developed preterm and early-onset preeclampsia than in those with normal pregnancies; and (2) at 80% specificity, a cutoff of 0.39 MoM had a sensitivity of 100% for early-onset preeclampsia and 85% for preterm preeclampsia. CONCLUSION: Maternal serum first-trimester PP13 appears to be a reasonable marker for risk assessment for preterm preeclampsia but a weak marker for severe preeclampsia at term, and ineffective for identifying mild preeclampsia at term.

First-trimester placental protein 13 screening for preeclampsia and intrauterine growth restriction.

OBJECTIVE: The purpose of this study was to evaluate first-trimester serum placental protein 13 (PP13) as a screening test for preeclampsia and intrauterine growth restriction (IUGR). STUDY DESIGN: We performed a prospective, nested case-control study in the Massachusetts General Hospital Obstetric Maternal Study. PP13 was measured by solid-phase sandwich enzyme-linked immunosorbent assay in serum samples that were collected at the first prenatal visit (9-12 weeks of gestation) from women who subsequently experienced preeclampsia (n = 47), IUGR (n = 42), or preterm delivery (n = 46). Women with uncomplicated term deliveries served as control subjects (n = 290) and were matched to cases by gestational age when serum was collected and for the duration of specimen storage. RESULTS: The median first-trimester PP13 level was 132.5 pg/mL in the control subjects. Median PP13 levels were significantly lower among women who had preeclampsia (27.2 pg/mL; P < .001), IUGR (86.6 pg/mL; P < .001), and preterm delivery (84.9 pg/mL; P = .007). When PP13 was expressed as multiples of the gestational age-specific medians among the control subjects, the multiples of the medians were 0.2 for preeclampsia, 0.6 for IUGR, and 0.6 for preterm delivery (P < .001 for each disorder compared with control subjects). Receiver operating characteristic analysis yielded areas under the curve of 0.91, 0.65, and 0.60 for preeclampsia, IUGR, and preterm delivery, respectively. At a 90% specificity rate, the corresponding sensitivities were 79%, 33%, and 28%, respectively. CONCLUSION: The screening of maternal PP13 levels in the first trimester is a promising diagnostic tool for the prediction of preeclampsia with high sensitivity and specificity.

Second-trimester uterine artery Doppler pulsatility index and maternal serum PP13 as markers of pre-eclampsia.

OBJECTIVE: To evaluate whether measurement of maternal serum PP13 at 22 to 24 weeks of gestation, alone or in combination with second-trimester biochemical markers or uterine artery pulsatility measured by Doppler velocimetry, is useful in predicting those women at risk of developing pre-eclampsia. STUDY DESIGN: A nested case-control study of pre-eclampsia cases with controls matched for gestational age and storage time for the maternal serum. PP13 was tested by an ELISA, with the samples blinded to pregnancy outcome. All patients also underwent uterine artery Doppler flow velocimetry at 22-24 weeks to measure the mean pulsatility index (PI). Results for Inhibin, Activin, PAPP-A and Free beta-hCG were available from previous studies. RESULTS: There were 73 controls and five cases with early pre-eclampsia in which delivery was induced prior to 35 weeks. In addition, there were a further seven cases with pre-eclampsia in which delivery was not induced before term. Median PP13 levels for controls and all cases were 295.9 and 212.6 pg/ml, and 171.2 pg/ml amongst the early pre-eclampsia cases, with the MoMs 1.00, 0.94 and 0.63, respectively (p < 0.001). Receiver operator characteristic (ROC) curve analysis for either all cases or early cases versus controls yielded areas under the curve of 0.588 (95% CI: 0.42-0.76; p = 0.1526) and 0.693 (0.47-0.92; p = 0.0441) for PP13. At a specificity set to 0.80, the sensitivity for PP13 in the early cases was 0.40 and that in all cases was 0.25. Combining PP13 bivariately with any of the markers (PI, PAPP-A, Activin, Inhibin or Free beta-hCG) tested in the 22-24 week period did not improve the detection of early, late or all cases of pre-eclampsia compared with either marker alone. CONCLUSION: Late second-trimester PP13 alone is unlikely to be useful in predicting pre-eclampsia and early pre-eclampsia, and its prediction does not increase when coupled with second-trimester Doppler PI or other potential biochemical markers. Measuring between-trimester temporal changes may be worthy of further investigation.